Can People Wire Two GFCI Outlets in Series for Safety and Efficiency?

Contemporary electrical installations often include GFCI (Ground Fault Circuit Interrupter) outlets to enhance safety, especially in hazardous conditions like wet areas. The viability of stringing two GFCIs in series may seem intriguing, but it's crucial to understand the implications and best practices.

Understanding GFCI Protection

One main reason for adding a GFCI outlet is to protect multiple outlets in a single circuit effectively. For instance, I once had a GFCI on the back porch also protecting the front porch. The lack of apparent power on the front porch led to a thorough investigation. Similarly, two bathrooms on different floors were protected by the same GFCI, ensuring a consistent level of safety across both locations.

When protecting multiple outlets, it’s essential to ensure that the second outlet is not on the load side of the first GFCI but rather on the line side. Ideally, only outlets that truly need protection should be GFCI-protected. One GFCI can often cover multiple outlets, provided they are on the same circuit.

Series vs. Parallel Wiring

AC outlets are never wired in series for power outlets, as this is a specific electrical connection that is not ideal for power outlets. Instead, they can be daisy chained or wired in parallel. GFCI outlets, however, can be daisy chained, but this approach generally does not add any significant benefit.

Each GFCI outlet can protect all downstream outlets on the same circuit, making the additional GFCI outlet redundant. The first GFCI will trip and protect everything wired under it. A race condition can occur where one GFCI may trip before the other, but it will not make the system any safer. Thus, wiring two GFCIs in series is unnecessary and wastes the second GFCI's protective capabilities.

Wiring a GFCI-Protected Circuit Correctly

While you can certainly wire multiple GFCI outlets, doing so is unnecessary. To ensure that one GFCI does not interfere with the other, proper wiring is key. The LINE side of the GFCI connects to the incoming power, while the LOAD side connects to any outlets beyond that specific GFCI.

To wire as asked, start at the first receptacle by pigtailing the hot (HOT), neutral (NEUTRAL), and ground (GROUND) wires and connecting them to the LINE side of the first GFCI. Nothing should be connected to the LOAD side at this stage. For the second GFCI downstream, connect the incoming power feed from the previous outlet to the LINE side and anything downstream (beyond the second GFCI) to the LOAD side.

The primary reason to do this is to avoid the hassle of traveling long distances to reset a single GFCI if one trips. However, it's essential to ensure that the wiring is done correctly to avoid any potential issues.

Conclusion

While it's permissible to wire GFCI outlets in series, it's not necessary and can be wasteful. GFCI outlets are designed to protect all downstream outlets on the same circuit, making additional GFCIs redundant. Always ensure that the wiring configuration is correct to avoid nuisance trips and maximize the protection provided.