Will a Ground Fault Circuit Interrupter (GFCI) Trip with Neutral Grounding?

We often equip circuits with residual current devices (RCDs) to maintain the safety of the wiring. So, will the neutral-grounding RCD trip?

Will the neutral-grounding RCD trip?

Yes, it can trip. To ensure balanced three-phase loads, the neutral wire should be at the same potential, meaning it should not carry any voltage. However, in reality, it is nearly impossible to achieve complete balance in three-phase loads, leading to a voltage on the neutral wire. When this voltage is connected through wiring, current will flow, which may cause a short circuit, resulting in the RCD tripping for protection.

When the neutral wire is connected to the ground wire, it interferes with the residual current monitoring of the RCD. If the currents in the phase and neutral wires are not equal, the switch will trip automatically.

What are the considerations for purchasing a residual current device?

1. When purchasing, prioritize selecting devices from qualified manufacturers and ensure that the products have passed quality inspections and obtained compliance certificates. This guarantees electrical safety, as the quality of RCDs in the market can be inconsistent, and many vendors may sell subpar products. Therefore, caution and diligence are essential during the selection process.

2. There are many types of residual current devices, so when selecting them, it is important to consider the features of the circuit and the surrounding environment to determine the device's current, voltage, tripping time, and other parameters. This will ensure effective protection.

3. If you want to implement tiered protection, the current rating of the upstream switch must exceed that of the downstream devices. This way, in the event of a fault, the upstream device can trip first, minimizing the impact of the incident and better safeguarding the property and personal safety of the users.

4. There are various types of residual current devices; typically, the rated current for standard environments should be below 30 mA. For areas like bathrooms and shower rooms, it should be less than 10 mA, and in places prone to accidents, it should be lower than 6 mA.

In summary:The above information discusses residual current devices. As we have seen, a neutral-grounding RCD can indeed trip. Moreover, there are more types and specifications of RCDs available in the market. It is crucial to choose products that meet your specific needs based on the actual circumstances to ensure the safety of the electrical circuit. I hope this information is helpful to everyone.