Electrical – Half Hot Outlet Tripping when Light is connected

electricalgfcireceptacle

I am hoping someone might be able to share some insight as to what I can next do to troubleshoot this problem.

In my room I have 3 outlets, the last one in the in circuit is a half-hot outlet connected to a switch by the door (there are no ceiling lights in the room). Everything has been working fine so far.

I decided to replace the 1st outlet in the circuit with a GFCI outlet as I plan on putting a small fish tank in the room.

After I added the GFCI outlet I noticed that it would trip whenever I flipped the "light switch" to the on position. I inspected the light switch and found the ground wire was not connected to the switch and therefore connected it. Now however, the GFCI only trips if I turn the switch on AND there is something connected to the switched part of the outlet. The always powered side of that outlet has worked without issue.

I removed the half-hot outlet to inspect the wiring and it is what I guess I would expect, tab between outlets on hot side removed, no bare or expose wires.

Does anyone have an idea as to what I can look at next?

Switch Box

Switch Box from Side

Half Hot Outlet box

Half Hot Outlet

Best Answer

You said that the tab on the hot side is broken and from that, I assume the tab on the neutral side is not broken. The problem is that the same neutral is being used for both the switched circuit and the load side of the GFCI.

A GFCI works by comparing the current through the hot and neutral wires. If the current is unequal, it assumes that current is escaping through the ground and trips. In your case, current from the switched circuit is returning through the GFCI. Since this current did not originate from the GFCI, it trips.

Because there isn’t a separate neutral that bypasses the GFCI, you cannot make this configuration work. Your choices are to either (1) abandon the switch and make the outlet always-hot or (2) put GFCI outlets where you want protection and not use the load sides; instead, use pigtail wires so that you can connect each outlet’s line side to the circuit. The half-hot outlet cannot have GFCI protection in this case.

The other option is to use a GFCI breaker to feed everything and restore the GFCI outlet to a normal outlet.