Connecting GE Smart Switch causes other regular switch & outlet to malfunction and/or not work

I’ve previously installed 4 GE Smart Switches in my home with no issues. However, when connecting this one in the same manner as before (& as stated in the instructions), other (ordinary/nonsmart) switches, outlets & light fixtures that are on the same circuit, no longer work correctly and/or at all.

Original wiring is: The hot line coming into the 2-gang box was pigtailed to 3 lines as follows:
1 - To an ordinary light switch in the 2-gang box, which controls a set of 3 outdoor light fixtures (which is the switch I am replacing with the GE smart switch);
2 - To the other ordinary light switch in the same 2-gang box, which controls an ordinary motion-sensing outdoor flood light); as well as,
3 - To an unswitched line that apparently runs across the room to an ordinary GFCI outlet and an ordinary motion-sensor light switch across the room (which controls 5 interior wall fixtures when sensing motion).

The 5 neutral white wires were all twisted together in a wire nut & not connected to anything, and the 5 copper ground wires are all tied together in a wire nut & not connected to anything.

The GE Smart Switch I am installing, is replacing the ordinary switch in the 2-gang box that controls the set of 3 outdoor light fixtures.

I labeled the lines & disconnected the old switch, and made the new connections to the new switch in the same manner as they were (connected the hot line to the line terminal and 2 load lines (from 3 light fixtures) to the load terminal), and connected the ground to the switch.

As “smart” switches require the neutral wire, I pigtailed the 5-wire bundle of white wires to the new switch, and turned the circuit breaker back on. The 3 light fixtures turned on & I paired the new switch to the Samsung SmartThings hub uneventfully. I also set the switch to turn the lights on automatically at sunset, & turn off at sunrise.

Then, I noticed the 5 wall light fixtures controlled by the motion switch across the room (from the unswitched line in the 2-gang box) would not turn off on its own when motion stopped, and also would not turn lights off manually by pressing the switch manually. The 5 wall light fixtures stayed on all night & turned off at sunrise. At which time, I realized the GFCI outlet (on the same unswitched line from the 2-gang box) also turned off at sunrise.

To correct that situation, I removed the neutral wire from the unswitched line in the box (that was pigtailed with the other 4 to the new switch) & capped it off with a wire nut. Now the 5 lights on the motion switch won’t turn on at all, & the GFCI does not work at all.

My first question I guess is, are ALL 5 neutral wires in the 2-gang box (& on the same circuit) supposed to be pigtailed to the neutral terminal on the smart switch? Or should just the neutrals from the hot line & the neutrals from the loads to the lights that are to be controlled by the smart switch, connected? Or some other scenario?

Hi Roxy,

Let me first start off by saying I’m not an electrician and would recommend using a licensed electrician when working with complex circuits.

That being said, I have wired many of these GE switches around my house and have come across similar situations. Regarding the white wires, I always keep these together.

The problem seems to be with the line/load wires. The unswitched circuit that is powering the GFCI and the motion sensor should be always hot and not controlled by the GE switch. I would go back and identify the black wires to identify the line from the breaker box (constant on) and the load wire to the outdoor lights and ensure they are wired into the GE switch properly.