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What is Earth Fault? It’s Causes, Effects and Protection

Table of Contents

What is Earthing and Grounding?

Earthing and grounding both are processes to connect electrical systems to the ground to protect people against electrical shock. The earthing  process means connecting the dead part of the electrical system (parts that don’t carry current under normal conditions such as the motor body, Transformer body, electrical panels, etc.) to the earth. Whereas the Grounding process means connecting the live part of the electrical system (parts that carry current under normal conditions such as neutral of star connected Transformer and loads ) to the earth. Now coming to our main topic of discussion:

What is Earth Fault?

Earth fault is an open circuit ground fault in which any live conductor or power-carrying cable is detached from its place or breaks and falls on the earth’s surface. In other words, We can say that ln earth-fault current-carrying conductor comes directly in contact with the earth’s surface. So because of the direct contact between a live conductor and the earth’s surface, a huge amount of current starts flowing to the earth due to the conducting nature of the earth.

Causes of Earth Fault

The main cause of earth fault in an overhead transmission and distribution line is the failure or puncture of the insulator. Insulators are used in overhead transmission lines to provide insulation between live conductors and metallic towers that are already connected with the earth’s surface. So if the insulation of insulator fails or in other words if the insulator is punctured then the fault current will flow through the live conductor and metallic tower to the earth creating an earth fault.

Another reason for earth fault is that sometimes overhead transmission lines break due to any unusual loads on line and hence fall to the ground. So in this case also live conductor gets in direct contact with the ground and creates a major earth fault in the electrical system. Whereas in the case of an underground PV cabling system, Earth fault may arise due to insulation damage during installation, abrasion damage to cable sheath, and damage to module back sheet during installation.

Effect of Earth Fault

Whenever an earth fault occurs in the electrical system than during earth fault, the System gets short, and hence huge amount of short-circuit current flows through the system. That huge current damages electrical equipment which comes in contact with a loop of earth fault circuits and also it interrupts the continuity of the power supply. Due to such a large amount of current flowing to the earth, a large voltage drop occurs that affects the other loads and it may cause the burning of phase or line.

How to check Earth Fault?

To identify the earth leakage fault in cables, megger is used. One terminal of the megger is connected to the live conductor and the other terminal is connected to the earth. If the merger indicates zero reading, it means the conductor is earthed. The same procedure is repeated for other conductors of the high-voltage cables.

Difference between Earth Fault and Ground Fault

Earth Fault  vs Ground Fault :

Earth fault is an open-circuit fault where a power-carrying cable or conductor breaks and gets into contact with Earth or any conductor capability material in contact with Earth. In this fault, the system at the load side is disconnected from the source in case of radial power flow.

Whereas a ground  fault is a short-circuit fault (such as L-G, L-L-G, L-L-L-G) where the power-carrying cable or conductor is not broken but gets into contact with the earth or any conductor capability material in contact with the earth. In this fault, the system at the fault point experiences the flow of a large amount of current into the ground.

Ground fault is more severe than earth fault due to flow of huge current to ground. That can dimage verious electrical equipments of power system, if fault is not cleared within specified time limits.

Earth Fault Protection

Well, after discussing the earth’s fault, its causes, and effects, one of the important questions that arises in our mind is.. ok, then what is the solution to minimize Earth-fault? Does it mean what protective equipment we can use to protect the earth fault? So let’s discuss the protection used to minimize earth faults in detail.

What are  Earth Fault Protection Devices?

The electrical equipment that   provides protection against earth fault is known as earth fault protection devices. These are normally Earth fault relay (EFR) , Earth leakage circuit breaker (ELCB) , and ground fault circuit interrupter, which are used to restrict the fault current. In these devices, the fault current is restricted and the fault is dispersed by the Restricted Earth Fault Protection (REFP) scheme. Now first let’s discuss both earth fault protection devices such as:

• Earth fault relay (EFR)
• Earth leakage circuit breaker (ELCB)

After that, we will see what is Restricted Earth Fault Protection (REFP) schemes.

Earth Fault Relay (EFR)

An earth fault relay (EFR) is a protection device used in electrical installation that can sense a fault between phase and earth.

The  main function of an earth fault relay (EFR) is to operate the CB for leakage current to the earth. RCCB also does the same function but RCCB gives protection to the human body, Whereas EFR provides protection to electrical equipment from earth fault . EFR deals with high voltage and high current.

Hence we can conclude that an earth fault relay (EFR) is an earth fault monitoring device that works on the principle of Kirchhoff’s law.

Earth Leakage Circuit Breaker (ELCB)

ELCB or earth leakage circuit breaker is a safety device used in electrical installation with high earth impedance to prevent electrical shock. In other words, we can say that ELCB is a special type of circuit breaker that is used for protection against earth leakage current. It is voltage voltage-sensing device that works on the concept of stray voltage. Whereas current sensing ELCB is also known as RCCB .

Whenever any earth leakage fault occurs in the system then a stray voltage appears across metal enclosures of electrical equipment ELCB interrupts the circuit if a dangerous voltage is detected. Then it disconnects the rest of the healthy system from the main supply. Once it tripped then it requires a manual reset process to work again normally.

Hence simply we can assume that ELCB is a safety device whose main function is to provide protection against electrical shock. It can’t assure protection against overloading and short-circuit faults.

What is the Restricted Earth Fault Protection (REFP) Scheme?

The restricted earth fault protection (REFP) scheme is very sensitive to internal earth faults for high-rating power transformers, alternators, etc. This scheme is comparatively cheaper than the differential protection scheme.

In this scheme, the common terminal of phase CTs is connected together with the secondary of neutral CT in such a manner that the secondary unbalanced current of phase CTs, and the secondary content of neutral CT will oppose each other.

When an external fault F 1 occurs in the system then the resultant of current I 1 and I 2 flowing through phase CTs and neutral CT respectively will be zero. But whenever an internal fault F 1 occurs inside the protective zone then only I 2 current will flow through the secondary of neutral CT and the resultant current will not be zero.

Hence earth fault relay will sense non-zero current and then it will operate the CB to protect the system with earth leakage fault . The fault current becomes 15% more than the rated current of each winding. To avoid magnetic inrush current, a stabilizing resistor is connected in series with an earth fault relay.

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Earth leakage explained

Earth leakage is electric current that finds its way to earth via an unintended path. There are two categories: unintentional earth leakage, which results from faulty insulation or equipment, and intentional earth leakage, which is a consequence of the way equipment is designed. It seems strange to “design in” earth leakage, but it’s sometimes unavoidable – IT equipment, for example, often produces some earth leakage, even when it’s working properly.

Whatever the source of earth leakage, it must be prevented from causing electric shocks. This is usually done by using either RCDs (residual current devices) or RCBOs (residual current circuit breakers with overcurrent protection). These measure the current in the line conductor and compare it with the current in the neutral conductor. If the difference exceeds the mA rating of the RCD or RCBO, it will trip.

Most of the time, earth leakage works as intended, but sometimes an RCD or RCBO keeps tripping for no apparent reason – this is “nuisance tripping”. The best way to tackle this is with an earth leakage clamp meter, such as the Megger DCM305E. This is clamped around the line and neutral conductors together (but NOT the protective conductor!) and it measures the earth leakage current.

To decide which circuit is causing nuisance tripping, turn off all the MCBs in the consumer unit and position the earth leakage clamp around the mains cables. Turn on each circuit in turn. If one causes the earth leakage to increase significantly, this is likely to be the problem circuit. Next decide whether the leakage is intentional. If it is, some form of load spreading or circuit splitting will be needed. If it’s unintentional leakage – the result of a fault  – the fault must be found and repaired.

Don’t forget the problem might be a faulty RCD or RCBO. To check, do an RCD ramp test. If it’s a 30 mA device – the most common rating – it should trip somewhere between 24 and 28 mA. If it trips at a lower current, it probably needs replacing.

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18th Edition: Earth leakage explained

Do you need to know if your cables are leaky? According to the 18 th Edition, the answer is ‘yes’, as Dave Sweetman, Marketing & Business Development Director at Di-LOG Group explains.

How often have you spent hours fault-finding nuisance tripping issues for free, wishing you’d have known there was a problem before quoting for this particular DB upgrade?

There is a new 18 th Edition regulation identifying the requirement for you to measure Earth Leakage, as stated in BS7671 Reg 531.33.2.

In a nutshell, each electrician must check that each install completed does not have excessive leakage to earth on each of the RCDs or RCBOs.

The maximum permitted value per RCD has been set at 30% of the nominal value, i.e. a 30mA RCD would be no more than 9mA, 100mA would be 30mA, and so on.

Nonetheless, I’m sure you’d find it useful to know if there is a potential issue on an installation before you quote for your next DB change.

The only way to indicate the presence of Earth Leakage would be to use an Earth Leakage Current Clamp Meter.

The Di-LOG DL6518 Earth Leakage Clamp is a low-cost solution that works on differential leakage measurement, which involves simultaneously clamping around the live and neutral conductors together.

You can check any installation by simply clamping around your meter tails on the supply.

The DL6518 has a measurement resolution of 100µA (0.1mA), making measurement very accurate when measuring minimal AC currents.

Domestic installations tend to have dual 30mA RCDs fitted or are even made up entirely of RCBOs.

If the installation shows a combined differential leakage current above 30% of each RCD/RCBO value (in this case 9mA) you may need to take action to manage the leakage to earth and minimise the likelihood of nuisance tripping.

We all know how costly call-outs are to any business to reset or investigate a tripping RCD!

Where possible, you will need to have the day-to-day electrical appliances in operation to accurately determine potential issues.

If excessive leakage is then identified on the tails, you would then need to clamp around the live and neutral conductors of each of the RCDs to determine if the leakage on that RCD is above the 30% threshold, ideally looking for a current considerably less than 9mA. You then repeat for each RCD.

Intentional or unintentional leakage

If the Earth Leakage detected on each RCD is excessive, the user will need to ask: “Is this intentional or unintentional?”

Intentional Earth Leakage tends to be found in electrical appliances in the form of a functioning earth, where a small amount of earth leakage is required for the appliance to function.

Unintentional Earth Leakage tends to occur in poor installations where there could be a breakdown in the conductor insulation or moisture ingress, amongst many other causes.

Identification

Switching each individual circuit off, one-by-one, is a good area to start.Here you can easily identify which circuit you may need to investigate further.

Once a circuit is identified, eliminate the ‘intentional leakage’ first by switching off each individual appliance, one-by-one, to see if this changes the result.

Every electrical appliance has a ‘Protective Earth Conductor current’ limit – you should refer to the In-Service Inspection and Testing Code of Practice for more information on these limits.

If the isolating of electrical appliances does not change the result it may well be ‘unintentional leakage’, and a check of the insulation of the conductors will be required in the form of an Insulation Test.

Leakage management

There are an array of options available to manage your Earth Leakage: balancing circuits between RCDs to fall below the 30% threshold, fitting RCBOs, testing the electrical appliances, or even a complete re-wire… all are critical when you price your next job!

Di-LOG has created a dedicated web page for readers of this article, containing all of the details you need to know about the DL6518 Earth Leakage Clamp, including special offers and technical specs. To visit the page go to: http://www.dilog.co.uk/pe-nov-2019-dl6518-earth-leakage-current-meter/

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Expert Advice On Improving Your Home

Troubleshooting a Tripped Circuit Breaker

Author, Editor

Alora Bopray

Staff Writer

Alora Bopray is a digital content producer for the home warranty, HVAC, and plumbing categories at Today's Homeowner. She earned her bachelor's degree in psychology from the University of St. Scholastica and her master's degree from the University of Denver. Before becoming a writer for Today's Homeowner, Alora wrote as a freelance writer for dozens of home improvement clients and informed homeowners about the solar industry as a writer for EcoWatch. When she's not writing, Alora can be found planning her next DIY home improvement project or plotting her next novel.

Roxanne Downer

Roxanne Downer is a commerce editor at Today’s Homeowner, where she tackles everything from foundation repair to solar panel installation. She brings more than 15 years of writing and editing experience to bear in her meticulous approach to ensuring accurate, up-to-date, and engaging content. She’s previously edited for outlets including MSN, Architectural Digest, and Better Homes & Gardens. An alumna of the University of Pennsylvania, Roxanne is now an Oklahoma homeowner, DIY enthusiast, and the proud parent of a playful pug.

Expert Reviewer

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Laurie Engle

Expert Writer & Reviewer

Laurie Engle is a freelance writer who provides insights to homeowners on topics such as the home warranty industry, relocation issues, and real estate trends. As a licensed Realtor since 2001 Laurie has acquired extensive expertise in dealing with home warranty companies and navigating the intricacies of the real estate market. In addition to her commitment to helping clients with their home buying and selling needs, she maintains a sharp awareness of market dynamics, including property values, interest rates, and local regulations.

May 30, 2024

A tripped circuit breaker can be frustrating to deal with. When your circuit breaker keeps tripping, finding the culprit can be a challenge. If your air conditioner or heat pump unit is the culprit that caused a circuit overload in your home or office, there are a few possibilities to explore.

These circuit breakers, found in your electrical panel are safety devices that protect the electrical wiring from further damage and homeowners from electrical shocks. In this article I’ll talk about two common reasons for circuit breaker trips — earth leakage and overcurrent — and help you with troubleshooting this electrical current issue.

Tripped Circuit Breaker Due to Earth Leakage

The earth leakage circuit breaker (ELCB) that trips the electrical power to the house when a lightning strike happens can easily be restored. Switch the lever from the OFF position back to the ON position.

In the case of faulty air conditioner equipment, the ELCB may trip due to earth leakage. In this case, you will need to isolate the cause of the power outage or repair the equipment before the flow of electricity can be restored to the entire home.

Here are some of the most common reasons that cause the earth leakage circuit breaker to trip.

The motor wires in the compressor touch the metal enclosure of the compressor. The wires of the compressor motor may come off due to excessive vibration or faulty design.

Once these wires that are connected to the hot circuits touch the metal enclosure which is grounded, current flowing to the ground causes the ELCB to trip.

Disconnect the electrical service power and all the circuits to the terminal of the compressor. Use a multimeter and set the scale to measure resistance. Check the resistance between each of the terminals to the enclosure.

If the reading is close to zero, that means that the exposed wire closest to that terminal has touched the metal frame. Repair the fault or replace the compressor before the equipment can be operated again.

Similarly, if the fault is due to the compressor fan motor or indoor blower motor, disconnect the power and isolate the circuits to the motor. Check the resistance of each terminal to the casing (if metal). If it is close to zero, that means that the exposed wire is touching the casing, causing it to trip. Remove the motor for repair or replace with a new motor before the equipment can be operational again.

In circuits that have live, neutral, and earth wires bundled together, there is a possibility that the insulator of the wires breaks down (due to overheating, faults, under specs or inferior wires). This breakdown causes the live or neutral conductor to touch the earth conductor. This will cause the circuit breaker to trip. Troubleshooting this problem is more complicated as it involves electrical circuits and not particular components.

Tripped Circuit Breaker Due to Overcurrent

If the miniature circuit breaker (MCB) trips, the fault could be an overcurrent or short circuit. An issue with the air conditioner may cause this circuit breaker to trip after it has been running for a while. This issue will take more time to troubleshoot as the problem does not happen immediately. Here are the possible causes.

Disconnect the mains power before checking the connecting power from the mains to the equipment. For example, if there are 3 terminals that connect the power to the compressor, open up the housing and check the connection.

Look out for darkened or black spots on the terminal indicating that an overcurrent has occurred. A loose connection will cause arching, thus drawing excessive supply and damaging the wires and the parts that are connected to it.

Tighten the connection after removing and reconnecting the wire that has been damaged due to overheating.

A licensed electrician will usually be able to troubleshoot this problem by using a tong clamp ammeter to measure the current of that particular conductor.

If the compressor has a mechanical part that malfunctions causing it to lock, the current to operate will be a few times more than the normal operation. When this happens continuously, the possibility of over-current to happen will occur, causing the circuit breaker to eventually trip after a certain period of operation.

If the compressor or fan motor uses a 3-phase induction motor, a loss of one phase will cause overheating to occur when operating at full load. If the thermal overload protection does not trip, the circuit breaker will trip if the current exceeds its specification. A good design has a phase loss protector built into the circuit to prevent the motor from running in the first place.

Effectively troubleshoot a tripped circuit breaker with a methodical and safe approach. For earth leakage issues, identify the faulty components such as the compressor or fan motor, or issues like shorted wires. Isolate the equipment, perform resistance checks with a multimeter, and repair or replace faulty parts. For overcurrent problems, pay attention to loose wire connections, potential compressor lock, and phase loss in three-phase systems. Make sure all connections are secure and verify the mechanical integrity of the compressor to prevent recurrent trips in your electrical system.

Circuit breakers are vital for protecting electrical circuits from damage, preventing electrical fires and electrical shocks. Perform regular maintenance and make repairs promptly to avoid future problems with tripped breakers.

Electrical safety is a priority when addressing electrical issues. I recommend you contact a qualified licensed electrician to repair your main breaker issues. The expertise of a professional electrician guarantees protection from electrical fires, overloaded circuits, and prolongs the lifespan of your equipment.

Expert Writer & Reviewer

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Earth leakage current : Measures & protection

Most of the electrical installations nowadays are having loads that incorporate electronics. These electronic loads influence the electrical installation in various ways:

• They generate harmonic distortion in the current they consume.
• They generate current leakages at the mains frequency, 50Hz, and at higher frequencies under normal operating conditions.
• As soon as they are connected to the electrical power supply they generate a leakage current point.
• During an insulation fault, the leakage current might not be sinusoidal, but rather pulsating, for example.

Computers, washing machines, dishwashers, microwaves, mobile phone chargers, low consumption light bulbs, ceramic hobs, air conditioning units, electric vehicle chargers, dryers, machine tools etc.

Q. What is Leakage Current?

Leakage Current is defined as the current which flows through protective ground conductor to ground. In the absence of grounding or improper grounding connections, it is the current that could flow from any conductive part or the surface of non-conductive parts to ground if any conductive path was available (i.e. human body). There are always extraneous currents flowing in the safety ground conductor.

Q. Why is it important?

Electrical equipment commonly includes a grounding system to provide protection against a shock hazard if there is an insulation failure. The grounding system usually consists of a grounding conductor that bonds the equipment to the service ground (earth). If there is a catastrophic failure of the insulation between the hot (power) line and touchable conductive parts, the voltage is shunted to ground. The resulting current flow will cause a fuse to blow or trip a relay and open a circuit breaker; preventing a shock hazard. Obviously, a possible shock hazard exists if the grounding connection is interrupted, either intentionally or accidentally. The shock hazard may be greater than supposed because of the leakage currents. Even if there is no insulation failure, interruption of the leakage currents flowing through the ground conductor could pose a shock hazard to someone touching the ungrounded equipment and ground (or other grounded equipment) at the same time. This possibility is of much more concern in medical applications, where a patient may be the recipient of the shock. A fatal shock could result if the patient is in a weakened condition or unconscious, or if the leakage current is applied to internal organs through patient contacts. The double insulation provided in non-grounded equipment provides protection by using two separate layers of insulation. The protection in this case is ensured because both layers of insulation are unlikely to fail. However, the condition that produce leakage currents are still present, and must be considered.

Q. What causes Leakage Current?

There are two types of leakage currents: ac leakage and dc leakage. Dc leakage current usually applies only to end-product equipment, not to power supplies. Ac leakage current is caused by a parallel combination of capacitance and dc resistance between a Voltage source (ac line) and the grounded conductive parts of the equipment. The leakage caused by the dc resistance usually is insignificant compared to the ac impedance of various parallel capacitances. The capacitance may be intentional (such as in EMI filter capacitors) or unintentional. Some examples of unintentional capacitances are spacings on printed wiring boards, insulations between semiconductors and grounded heat sinks, and the primary-to-secondary capacitance of isolating transformers within the power supply. Consequences Earth Leakage current beyond 30mA can be lethal leading to death. 30mA sensitivity is required for protection in domestic applications where the person may come in direct contact with electric equipment in locations such as labs, schools, workshops etc.100mA and 300mA protection is required where there is indirect contact or due to insulation failure in the cables.

Q. How is it measured?

A meter specially designed for measuring leakage currents is used. The current flowing in the ground conductor is measured by connecting the meter in series with the grounding connection. For information processing equipment, the ground connection is opened and the current flowing to the neutral side of the power line is measured. For medical equipment, the current flowing to ground is measured. The meter may also be connected between the outputs of the power supply and ground. The test conditions include swapping the ac line and neutral connections, and turning power switches off and on while monitoring the current. The test is performed after the equipment has warmed to normal operating temperature and, in some cases, following certain test that cause abnormally high temperatures within the equipment. The intent is to identify and measure the worst-case leakage current.For very low leakage currents, the meter is replaced with a network consisting of either a resistor or a resistor and capacitor combination. The voltage drop across the network is then measured using a sensitive ac voltmeter. Ungrounded or double-insulated equipment is checked by connecting the meter between any touchable conductive part and ground. In the case of non-conductive housings, a copper foil of a specific size is placed on the housing, and the current flowing from it to ground is measured.

Q. How can you get your equipments protected from Leakage Currents?

So how can you get your equipments protected from the leakage currents or how can you eliminate the effects of leakage current? Quantify the leakage current and then identify the source. One best way of going about this is to use Earth Leakage Relay (ELR). The Earth Leakage Relay with Core Balanced Current transformer provides protection from earth leakage with advance intimation (Pre-alarm) of impending occurrence of the event. The user can proactively take action to avoid occurrence of any mishaps. Rishabh’s ELR with 4 digit 7 segment LED display with True RMS measurement (as per IEC 60947-2 Annex M) provides the user with benefits that go the extra mile. Rishabh’s ELR is a microcontroller based device designed to measure low level of leakage current and isolate the faulty equipment or circuit from the system. Leakage current is sensed through Rishabh’s Core Balanced Current Transformer. Fixed time trip occurs when Earth Leakage Current exceeds the trip time which is programmable by means of front keys provide on the front panel of the relay or PRKAB software (can be provided optionally with Rishabh’s ELR). The user can program the threshold level ranging from 30mA to 30A. In case of earth leakage the LED indicators will glow depending upon the percentage of programmed threshold value. For e.g. If the set level is 30mA and the leakage current is more than 15mA then green LED will start blinking which will provide a visual alert to the user. This empowers the user to take corrective actions before any accident. Core Balanced Current Transformer (CBCT) uses the technology of residual magnetic flux. All conductors to be protected shall pass through the core balance current transformer. The vector sum of all the currents should be equal to zero.

In case an earth leakage occurs, the zero- sequence fault current which flows is not cancelled by the flux of the other two phases and hence induces current (residual current) in the secondary. The core balance current transformer can be connected to an earth fault / leakage relay which can be used to generate the tripping signal. CBCTs are manufactured with one core and one secondary winding. The number of secondary turns does not need to be related to the cable/feeder rated current because no secondary current would flow under normal balanced conditions. This allows the number of secondary turns to be chosen such as to optimize the effective primary pick up current. The choice of ratio should therefore be left to the manufacturer to obtain the best possible results.

If more than one 3-phase cable are used in parallel, it is recommended that a separate CBCT on each cable be connected across a common relay or a separate relay be provided for each CBCT. The cable on which the CBCT is mounted acts as the primary conductor of the CBCT. Under normal operating conditions, the three line currents are almost 120 degree apart and balance each other. The resultant secondary current is zero. Upon occurrence of an earth fault, the faulted phase is the only one experiencing earth fault current in the primary. The maximum value of current is decided by the system earthing conditions. The CT wires should be placed adequately away from high current carrying conductors or source of strong magnetic field to avoid noise pickup.

Customer shall provide following information while ordering a CBCT :-

• Cable size or minimum ID require for CBCT
• Minimum earth leakage current to be detected by CBCT + Relay combination
• Specifications of the relay to be used including burden & setting range available
• Choice of ratio

Mr. Santosh R. Bhangale Product Manager Rishabh Instruments Pvt. Ltd. Nasik – India

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Is Your Earth Leaking? – Basics of Earth Leakage Circuit Breakers

Earth leakage is an unintended state where electrical current is leaking from an electrical appliance or circuit to earth (ground). Earth Leakage Circuit Breakers are used to protect people and equipment from electrical shocks and against fire risks due to current leakage.

They fall into two types: Current Sensing Breakers and Voltage Sensing Breakers.

Current Sensing Breakers

The most common type of earth leakage circuit breaker in use now is the current sensing breaker or residual current circuit breaker (RCCB). They monitor the difference between current flowing through the phase and neutral wires. An imbalance between phase and neutral causes the breaker to trip, protecting against potential hazards like accidents, fire, or equipment damage.

Current sensing breakers consist of a current transformer with two primary windings and one secondary winding acting as the sensing coil. The primary windings support the phase and neutral wires. When the current flowing through the phase and neutral are equal they create opposing magnetic fields and no current flows through the sensing coil. When there is earth leakage the magnetic fields are not in balance, generating a current through the secondary winding thus causing the breaker to trip.

Advantages of current sensing breakers:

• Can detect any earth fault whereas voltage sensing only detects faults in the main earth connection.
• Can detect changes in phase and neutral currents.
• Are efficient and inexpensive.
• Require fewer connections than voltage sensing breakers.

Current sensing breakers have the disadvantage of nuisance tripping when an electric load suddenly changes and some current goes to earth despite there being no risk of shock.

Voltage Sensing Breakers

Voltage sensing breakers are older and less commonly used now than current sensing breakers. Voltage sensing breakers require a ground connection, unlike current sensing breakers which do not require this connection, to measure earth leakage. They contain a trip coil that senses voltage.

During normal operating conditions, there will not be voltage across the trip coil. When an earth fault occurs, such as line voltage contacts the metal enclosure of the protected device, voltage will cross the trip coil causing the breaker to trip. This protects the equipment and anyone who comes in contact with the electrical devices.

While still in use, voltage sensing earth leakage circuit breakers are generally not used in new projects due to their disadvantages.

Disadvantages of voltage sensing breakers:

• They require extra connections between the source and the breaker.
• Any wiring breaks to earth or live current generates a failure which could result in severe shock hazards to people.
• Other devices connected to the earthing system can generate voltages that cause the breaker to trip.
• They do not provide shock protection if the line conductor is touched.

Explore MISUMI’s selection of earth leakage breakers here .

About the Author

Mike is the Product Manager for Industrial Electronics at MISUMI. He has over 15 years’ combined experience working in Industrial/MRO distribution and Electronic Components distribution. He holds a Bachelor’s Degree from Northern Illinois University.

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Power Tripped? Common Causes and What to do

by Peter Cardamone | Oct 2, 2020 | Domestic Electrical , Emergency Electrical | 0 comments

Having something trip the power in your home can be an extremely frustrating occurrence – especially if you’re in the middle of a task, and particularly if you don’t know what has caused it. Often, the problem may be simpler than you think. There are a few reasons why your power might have tripped. Even better, there are simple steps to follow to fix the problem quickly and easily, allowing you to get on with your day.

Causes of a Power Trip

Essentially, a power trip occurs when the electrical system in your home is compromised in some way. The trip is a safety mechanism, meaning your circuit breakers will ‘trip the switch’ and automatically shut down power to one or several systems, making sure the problem cannot become anything more serious. This can happen for a number of reasons.

Overloaded Circuit

The most simple cause of a power trip is an overloaded circuit. If you have too many devices or appliances running simultaneously, the circuit can end up drawing more electrical load than it is equipped to handle. It heats up, the circuit breaker senses this, and the power trips before the circuit can heat to a dangerous level.

Short Circuit

A short circuit can be caused by a wiring problem in a device or an appliance when it is connected to your main system. It can also happen if two opposing wires accidentally touch, causing an unexpected surge of electricity that will cause the circuit breaker to trip the system.

Earth Leakage Fault

An earth leakage fault is a type of short circuit, and it will happen when the current flowing through the electrical system finds an alternative path other than the active or neutral conductors. These are slightly more dangerous, particularly if they occur in places such as the bathroom or kitchen where moisture could carry the electricity and cause shocks. Once again, the increase in electricity will cause the circuit to heat up, and the circuit breaker will therefore initiate a power trip to prevent further damage.

What to Do About a Power Trip

In the case of a short circuit or a ground fault, it is advisable to promptly seek professional advice in order to resolve the problem safely. If you live in the south-east, you may want to call your electrician in Brighton and get a specialist to take a look at the problem. However, in the case of an overloaded circuit, you can often fix the problem yourself in a few simple steps.

Before any fault occurs, it’s useful to ensure you know where your electrical board is located, and you have a handheld torch to help you navigate in case of a blackout.

Turn Appliances Off

Make sure to turn any appliances off that are connected to the affected system.

Master Switch

At the power board, your first move should be to turn off the master switch. This will ensure you cannot get hurt whilst fixing the problem.

Safety Switch

Make sure you have an RCD safety switch installed , and use it to check the safety of your appliances.

Once you have flipped the relevant switch back to the ‘on’ position, test that the circuit is working again. If it is not, or if it immediately trips again, it may be that the problem is more severe than an overloaded circuit, and it’s time to call in the professionals.

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What are the possible causes of an earth leakage trip in the installation?

If the earth leakage circuit breaker has been activated, it may have been an earth leakage, short circuit or overcurrent situation.

An 'earth leakage trip' means that an earth leakage current has been detected. This usually indicates there is an issue with the leakage current of the installation or of the vehicle.

We advise to contact the installer or operator of the charging station for inspection and possible repair. Are you the operator? You can submit a 'Request for Service' ticket via support.alfen.com .

The 5 Most Common Electrical Faults Plaguing South Africa

Electricity has become a part of our daily lives and as long as everything is working properly, we probably aren’t paying much attention to it. But when load shedding occurs or our DB board trips, our reliance on electricity for pretty much everything we do is very readily apparent. 

Over the years, we have been called out to fix many electrical faults, and we have noticed that some problems crop up far more often than others. Here are the five most common faults that we see in homes around the country, and why you shouldn’t just leave them alone.

Common Electrical Faults

Plugs not working.

If a power outlet in your home isn’t working properly, this can be very dangerous! An outlet that doesn’t work could be caused by a problem in several areas, from the outlet itself to the wires in your walls and ceiling, or it could be a problem with that whole circuit. Even if you unplug everything from that wall socket, a damaged cable in the wall could lead to problems, from tripping your Earth leakage, to causing a fire in your wall or ceiling! This type of electrical fault is often left ignored, until it creates a major problem. Rather get the plug disconnected completely if you have no need for it.

Lights not working

Do you have a light fitting that feels unlucky compared to the others? If you have downlights that you keep replacing the bulbs, or one room seems to need new bulbs faster than all the others, this can indicate a loose connection. Downlights are sensitive to several things, including temperature changes, vibrations and any change in voltage. If you are replacing bulbs in a specific fitting more often than the lights nearby, you should have an electrician check for loose connections that could be causing the problem.

Earth leakage tripping

This is a serious problem that should be addressed as soon as possible! Your Earth leakage circuit breaker is a safety mechanism, and if something is happening that is causing it to trip, then it could indicate that something dangerous is happening inside your home. If your Earth leakage is tripping, this could indicate a short-circuit, an overloaded circuit, or that a circuit is leaking electricity https://www.energymatters.com.au/marketplace/do-you-have-an-electricity-leak-heres-your-guide-to-find-out/ . Contact an electrician to find the fault, as you could be putting your family at risk.

Geyser not working

Geysers require a fair amount of power and are often somewhere hard to reach! They have their own dedicated circuit, and there is a breaker near the geyser to make sure that they can’t be turned on by accident while someone is working on them. As useful as geysers are, they involve water, and water and electricity are a dangerous combination! A leaking geyser could drip water onto wires or electrical components, which will cause the system to trip. If you have a geyser that stops working properly, be careful about trying to find the problem and fix it yourself!

Circuit breaker tripping

If any of these issues sound familiar, contact us today and get it fixed before it becomes a bigger problem.

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Geyser tripping main switch: causes and solutions

The geyser in your bathroom or kitchen is definitely one of the most important home appliances there is. Not just it heats water for your bathing needs but also for various other purposes such as washing utensils, cooking food and many others. But geysers can encounter certain problems from time to time which may be solvable but can create temporary problems. One of such issues is geyser tripping main switch.  There can be many reasons for this and the solution will depend upon the cause. Thus we have listed the main reasons for geyser tripping main switch as well as the solutions:

1. Water dripping on the electrical lines

REASON: One of the most common reasons for geyser tripping main switch is water dripping on the electrical lines.  It is a fact that a leak which allows water to drip on or contact with any electrical parts or components can prove to be dangerous.  This leak can be caused due to a failing gasket which must be repaired.

SOLUTION: It is suggested that you contact a professional for repair purpose as it can prove risky to do this on your own.

2. A malfunctioning thermostat

REASON: Another common cause for geyser tripping main switch is a malfunctioning thermostat.  Thermostat is an important part of the appliance. It helps you control the temperature of the water that the geyser heats.

SOLUTION: If it becomes faulty then it is important to replace it, especially in the case of tripping of the circuit breaker.  In this case it may be a good idea to replace the heating element as well. You can check the functioning of the thermostat through a multimeter.

HTC Instrument Mas 830L

Features: 3½ digit LCD display with backighting data hold transistor and amp

Here are some other Multipurpose Multimeters your can find online:-

• HTC Instrument Mas 830L Digital Pocket Multimeter Dmm 
• Uni-T Ut-33D Digital Multimeter With Continuity Buzzer 
• Freshdcart DT-266 Clamp Multimeter Auto Ranging Amp Current Voltage Measurement Device 
• Mextech DT-603 Digital Multimeter 

3. Burnt out heating element

REASON: If none of the above given points are not the reasons for your geyser tripping main switch, then the possible cause could be burnt out heating element. Most geysers have two heating elements-one at the top and the other at the bottom.  When the heating elements fail, they simply burn out and the best way to detect this is when you observe that the water isn’t as hot as it used to be. In some cases, the heating element casing may split up and may expose the electrical components directly to the tank or water.  This may result in the short circuit flipping the high limit switch on the geyser and result in tripping of the main switch.

SOLUTION: The only solution here is to replace the heating element altogether.

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Some of the other Heating Elements available online are:-

• RACOLD Eterno/Altro Geyser Heater Element 
• Litost® Geyser Heating Element 2 KW Triangle Tikoni Type With Pocket (Only For OLD USHA Type Geyser) 
• Vardhman- THEETA Brand Instant Water Heating Element 
• Vardhman- THEETA Brand Heating Element (Only for Bajaj Type Geyser) 
• Litost® Heating Element For Geyser (Only For Havells & Recold Type Elements) 

4. Poor electrical wiring

REASON: Another common reason for geyser tripping main switch could be poor electrical wiring.

SOLUTION:  If a wire has become loose in the electrical panel then you must contact a professional to get the electrical wiring changed or replaced.

Image Credits: Wikimedia Commons

Now that you know the main causes of geyser tripping main switch you can easily solve the issue with the solutions suggested. However for any kind of professional help or replacement work, you can contact Mr Right.  They can help you with general home appliances repairs or any geyser related troubles.

Bajaj Splendora 3L 3KW IWH Instant Water Heater

Copper heating element with efficient longer life. Unique Weldfree joint in outer metal body. It come with fire retardent cable and neon indicator for heating

If you are looking for a new Geyser, we have some recommendations for you: –

• Bajaj New Shakti Storage 25 Litre Vertical Water Heater 
• AO Smith Storage 25 Litre Vertical Water Heater 
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• Causes and solutions for an overheating geyser - July 7, 2017
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12 comments.

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Seems this 3KW Bajaj instant geyser is having issues. As in, after turning it on, we have good hot water coming and after around 3-4 minutes the MCB switch will trip. We have a 16A MCB switch connected to this geyser and it can use for next bath almost after 4-5 minute. This issue objarved in monsun/rainy and winter season so give your feedback on the same… 1. Confirm 16 A mbc switch is enough or more? 2. Wiring is checked with electrician.

My geyser was tripping the main, I then switched that off for 48 hours, got a plumber, switched it on and no tripping but water not getting hot? We then you replaced the element (which had holes in it), thermostat, thermostat pocket and t&p valve and reconnected wires; switched the main back on and nothings happening, there’s sound by the geyser, nor is the main tripping, what could be wrong?

…there’s no sound by the geyser

I’m also having the same problem

I have tried to replace thermostat still in vain can I replace the the circuit breaker?

Geyser heats up fine ,one element,Sounds like my thermostat??

I think there is a leakage and water is dripping to one of the conductors. Initially the thermostat was faulty and as it was replaced, it was not properly fitted and hence a leakage.

Hi we recently had our thermostat replaced in our geyser. It was causing water to not heat and power to trip. There were no tripping issues before this happened. Since the plumbers have replaced the thermostat not even a month later and power is tripping again. They say it’s not the thermostat and it’s not the element (not sure how they checked this?) they say it’s the wiring from the circuit breaker to the geyser. This does not sound right to us as we have been in this house for almost 20 years and never had a faulty circuit breaker?? Please help?

I’m also having the same problem but I’m trying to find out what’s going if got something I will let you know.

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How Close Are the Planet’s Climate Tipping Points?

Earth’s warming could trigger sweeping changes in the natural world that would be hard, if not impossible, to reverse.

By Raymond Zhong and Mira Rojanasakul

Right now, every moment of every day, we humans are reconfiguring Earth’s climate bit by bit. Hotter summers and wetter storms. Higher seas and fiercer wildfires. The steady, upward turn of the dial on a host of threats to our homes, our societies and the environment around us.

We might also be changing the climate in an even bigger way.

For the past two decades, scientists have been raising alarms about great systems in the natural world that warming, caused by carbon emissions, might be pushing toward collapse. These systems are so vast that they can stay somewhat in balance even as temperatures rise. But only to a point.

Once we warm the planet beyond certain levels, this balance might be lost, scientists say. The effects would be sweeping and hard to reverse. Not like the turning of a dial, but the flipping of a switch. One that wouldn’t be easily flipped back.

Mass Death of Coral Reefs

Tipping point possible

Degrees of warming

When corals go ghostly white, they aren’t necessarily dead, and their reefs aren’t necessarily gone forever. Too much heat in the water causes the corals to expel the symbiotic algae living inside their tissues. If conditions improve, they can survive this bleaching. In time, the reefs can bounce back. As the world gets warmer, though, occasional bleaching is becoming regular bleaching. Mild bleaching is becoming severe bleaching.

Scientists’ latest predictions are grim. Even if humanity moves swiftly to rein in global warming, 70 percent to 90 percent of today’s reef-building corals could die in the coming decades. If we don’t, the toll could be 99 percent or more. A reef can look healthy right up until its corals start bleaching and dying. Eventually, it is a graveyard.

This doesn’t necessarily mean reef-building corals will go extinct. Hardier ones might endure in pockets. But the vibrant ecosystems these creatures support will be unrecognizable. There is no bouncing back anytime soon, not in the places corals live today, not at any scale.

When it might happen: It could already be underway.

Abrupt Thawing of Permafrost

In the ground beneath the world’s cold places , the accumulated remains of long-dead plants and animals contain a lot of carbon, roughly twice the amount that’s currently in the atmosphere. As heat, wildfires and rains thaw and destabilize the frozen ground, microbes get to work, converting this carbon into carbon dioxide and methane. These greenhouse gasses worsen the heat and the fire and the rain, which intensifies the thawing.

Like many of these vast, self-propelling shifts in our climate, permafrost thaw is complicated to predict. Large areas have already come unfrozen, in Western Canada, in Alaska, in Siberia. But how quickly the rest of it might defrost, how much that would add to global warming, how much of the carbon might stay trapped down there because the thawing causes new vegetation to sprout up on top of it — all of that is tricky to pin down.

“Because these things are very uncertain, there’s a bias toward not talking about it or dismissing the possibility, even,” said Tapio Schneider, a climate scientist at the California Institute of Technology. “That, I think, is a mistake,” he said. “It’s still important to explore the risks, even if the probability of occurrence in the near future is relatively small.”

When it might happen: The timing will vary place to place. The effects on global warming could accumulate over a century or more.

Collapse of Greenland Ice

The colossal ice sheets that blanket Earth’s poles aren’t melting the way an ice cube melts. Because of their sheer bigness and geometric complexity, a host of factors shapes how quickly the ice sheds its bulk and adds to the rising oceans. Among these factors, scientists are particularly concerned about ones that could start feeding on themselves, causing the melting to accelerate in a way that would be very hard to stop.

In Greenland, the issue is elevation. As the surface of the ice loses height, more of it sits at a balmier altitude, exposed to warmer air. That makes it melt even faster.

Scientists know, from geological evidence, that large parts of Greenland have been ice-free before. They also know that the consequences of another great melt could reverberate worldwide, affecting ocean currents and rainfall down into the tropics and beyond.

When it might happen: Irreversible melting could begin this century and unfold over hundreds, even thousands, of years.

Breakup of West Antarctic Ice

At the other end of the world from Greenland, the ice of western Antarctica is threatened less by warm air than by warm water.

Many West Antarctic glaciers flow out to sea, which means their undersides are exposed to constant bathing by ocean currents. As the water warms, these floating ice shelves melt and weaken from below, particularly where they sit on the seafloor. Like a dancer holding a difficult pose, the shelf starts to lose its footing. With less floating ice to hold it back, more ice from the continent’s interior would slide into the ocean. Eventually, the ice at the water’s edge might fail to support its own weight and crack into pieces.

The West Antarctic ice sheet has probably collapsed before, in Earth’s deep past. How close today’s ice is to suffering the same fate is something scientists are still trying to figure out.

“If you think about the future of the world’s coastlines, 50 percent of the story is going to be the melt of Antarctica,” said David Holland, a New York University scientist who studies polar regions. And yet, he said, when it comes to understanding how the continent’s ice might break apart, “we are at Day Zero.”

When it might happen: As in Greenland, the ice sheet could begin to recede irreversibly in this century.

Sudden Shift in the West African Monsoon

Around 15,000 years ago, the Sahara started turning green. It began when small shifts in Earth’s orbit caused North Africa to be sunnier each summer. This warmed the land, causing the winds to shift and draw in more moist air from over the Atlantic. The moisture fell as monsoon rain, which fed grasses and filled lakes, some as large as the Caspian Sea. Animals flourished: elephants, giraffes, ancestral cattle. So did humans, as engravings and rock paintings from the era attest. Only about 5,000 years ago did the region transform back into the harsh desert we know today.

Scientists now understand that the Sahara has flipped several times over the ages between arid and humid, between barren and temperate. They are less sure about how, and whether, the West African monsoon might shift or intensify in response to today’s warming. (Despite its name, the region’s monsoon unleashes rain over parts of East Africa as well.)

Whatever happens will matter hugely to an area of the world where many people’s nutrition and livelihoods depend on the skies.

When it might happen: Hard to predict.

Loss of Amazon Rainforest

Besides being home to hundreds of Indigenous communities, millions of animal and plant species and 400 billion trees; besides containing untold numbers of other living things that have yet to be discovered, named and described; and besides storing an abundance of carbon that might otherwise be warming the planet, the Amazon rainforest plays another big role. It is a living, churning, breathing engine of weather.

The combined exhalations of all those trees give rise to clouds fat with moisture. When this moisture falls, it helps keep the region lush and forested.

Now, though, ranchers and farmers are clearing the trees, and global warming is worsening wildfires and droughts. Scientists worry that once too much more of the forest is gone, this rain machine could break down, causing the rest of the forest to wither and degrade into grassy savanna.

By 2050, as much as half of today’s Amazon forest could be at risk of undergoing this kind of degradation, researchers recently estimated.

When it might happen: Will depend on how rapidly people clear, or protect, the remaining forest.

Shutdown of Atlantic Currents

Sweeping across the Atlantic Ocean, from the western coasts of Africa, round through the Caribbean and up toward Europe before heading down again, a colossal loop of seawater sets temperatures and rainfall for a big part of the globe. Saltier, denser water sinks to the ocean depths while fresher, lighter water rises, keeping this conveyor belt turning.

Now, though, Greenland’s melting ice is upsetting this balance by infusing the North Atlantic with immense new flows of freshwater. Scientists fear that if the motor slows too much, it could stall, upending weather patterns for billions of people in Europe and the tropics.

Scientists have already seen signs of a slowdown in these currents, which go by an unwieldy name: the Atlantic Meridional Overturning Circulation, or AMOC. The hard part is predicting when a slowdown might become a shutdown. At the moment, our data and records are just too limited, said Niklas Boers, a climate scientist at the Technical University of Munich and the Potsdam Institute for Climate Impact Research.

Already, though, we know enough to be sure about one thing, Dr. Boers said. “With every gram of additional CO2 in the atmosphere, we are increasing the likelihood of tipping events,” he said. “The longer we wait” to slash emissions, he said, “the farther we go into dangerous territory.”

When it might happen: Very hard to predict.

Read More on Earth’s Tipping Points

Heat Raises Fears of ‘Demise’ for Great Barrier Reef Within a Generation

A new study found that temperatures in the Coral Sea have reached their highest levels in at least four centuries.

By Catrin Einhorn

A Collapse of the Amazon Could Be Coming ‘Faster Than We Thought’

A new study weighed a range of threats and variables in an effort to map out where the rainforest is most vulnerable.

By Manuela Andreoni

In the Atlantic Ocean, Subtle Shifts Hint at Dramatic Dangers

A warming atmosphere is causing a branch of the ocean’s powerful Gulf Stream to weaken, some scientists fear.

By Moises Velasquez-Manoff and Jeremy White

How Much Ice Is Greenland Losing? Researchers Found an Answer.

The island is shedding 20 percent more than previously estimated, a study found, potentially threatening ocean currents that help to regulate global temperatures.

By Delger Erdenesanaa

Rapid Antarctic Melting Looks Certain, Even if Emissions Goals Are Met

It may be too late to halt the decline of the West Antarctic ice shelves, a study found, but climate action could still forestall the gravest sea level rise.

By Raymond Zhong

Methodology

The range of warming levels at which each tipping point might potentially be triggered is from David I. Armstrong McKay et al., Science .

The shaded areas on the maps show the present-day extent of relevant areas for each natural system. They don’t necessarily indicate precisely where large-scale changes could occur if a tipping point is reached.

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