An RCCB that will not trip when or as needed can be a major risk to electrical safety. This article aims to help identify common RCCB tripping problems, their causes and offer solutions. In other words, it will explain RCCB tripping reasons, tripping issues, and the steps to take when the device does not operate as intended.
RCCB tripping refers to when it reacts to a fault current in the power circuit. This happens when the circuit breaker detects changes in the incoming live and outgoing neutral wire currents. The RCCB trips to protect people and equipment from electric shocks or even possible fires.
The RCCB tripping mechanism comprises two parts; the trip unit and the sensing coil. The trip unit is essentially a mechanical device that disconnects the defective circuit from the power supply during a fault.
On the other hand, the sensing coil is a current transformer that measures the current in the live and neutral lines. If it exceeds the tripping threshold of the specific breaker, tripping will occur and open the circuit.
Why RCCBs Trip
Different power system faults can cause the RCCB to trip. Usually, if there’s an imbalance between live and neutral wires due to line-to-earth connections or earth leakage, the RCCB trips. RCCB tripping reasons can be divided into the following:
RCCB Split Load Tripping
Most often, an RCCB is installed on a split load consumer unit. This is a unit that’s meant to provide protection to different circuits. One RCCB, for example, may protect lighting and power points downstairs, with another protecting the same circuits upstairs.
Split load RCCB tripping only involves the affected circuit and not the other circuits. This is due to the split load arrangement, which is designed to limit the disconnection of all circuits at once. In this scenario, an RCCB will trip if some current leaks to the ground.
RCCB Trip During Lightning
Lightning strikes can cause a significant amount of electrical energy into a building’s electrical system, and potentially cause damage to equipment or create safety hazards. In some cases, that may lead to the RCCB tripping and cutting off the power supply to the circuit.
RCCB tripping during lightning conditions does not mean a defective electrical system or breaker. It simply means the RCCB has done its job by detecting a dangerous fault and has shut off power to the circuit, thus protecting you from possible harm or property damage.
RCCB Tripping Problems
RCCB tripping problems mean trips that are not caused by normal electrical faults in the system. This may be due to incorrect installation, equipment failure, aging, or dirt build-up on the trip unit contacts. These can be divided into three categories: false trips, delayed trips, and non-tripping RCCB.
RCCB Keeps Tripping
The RCCB trips frequently, even when no fault is present. If the RCCB keeps tripping for no reason, the problem could be a faulty system or even the RCCB itself. In this case, the only solution is to determine the fault and fix it. You may also want to check if the breaker is correctly rated for the system.
RCCB Not Tripping
RCCB tripping problems include situations when the breaker will not trip despite a fault in the system. Reasons for an RCCB not tripping include a faulty trip unit, incorrect wiring, or dirt build-up on the contacts. Most often, this is caused by a problem within the device itself.
Tripping Time of RCCB
The tripping time of RCCB breakers means the time it takes for the breaker to detect and respond to a fault. This is usually determined by the type of RCCB, the current load, and the sensitivity setting of the trip unit.
Generally, RCCBs are designed to have very fast tripping times in order to protect equipment or personnel from electric shocks or fire hazards. If the RCCB tripping time is too slow, it can also mean an incorrectly rated or selected RCCB.
How to Test RCCB
RCCB tripping problems result in a protection device that you cannot rely on in the event of an earth fault. To ensure that your system’s RCCB will trip when required, we recommend that you regularly test and inspect it. Below, we show you how to test RCCB breakers in two ways: using the test button and with the help of a testing kit.
How to Test RCCB Using Test Button
The RCCB test button is positioned on the face of the device. When pressed, it simulates a fault condition, which should cause the RCCB to trip. To use it, follow these simple steps:
- Locate the residual current circuit breaker (RCCB) on the electrical panel.
- Find the test button on the face of the device.
- This will usually be marked with the words “TEST” or a “T” symbol.
- Press this test button.
- If the RCCB is working correctly, the trip switch should audibly flip down
- This will cut off power supply to any connected circuits.
- To restore power, simply flip up the tripped switch.
How to Test RCCB with Testing Kit
To perform a more accurate test, you need a testing kit. This is a device that can help you professionally identify a fault, confirming if the RCCB is working correctly.
To use it, connect the testing kit to both terminals of your RCCB. The kit tests the RCCB tripping time and how quickly it can detect and respond to a fault. If it passes the test, you can be sure that your RCCB is functioning correctly.
By regularly testing and inspecting your RCCBs, you can ensure that they are providing their intended protection. This will help to keep your building and its occupants safe from electrical hazards.
RCCB tripping problems can lead to dangerous situations, such as electric shocks or fire hazards. To ensure that your RCCB is functioning correctly and providing the intended protection, be sure to regularly test and inspect it. This can be done either by pressing the test button on the face of the RCCB or using a testing kit. Remember, a working RCCB is essential for the safety of your building and its occupants.