I have two switches by the front door. One controls the exterior door light. The other controls a light on a pole by the driveway. I want to replace the two switches with a single timer switch that turns both lights on at dusk and off at some later time.
There is a GFCI outlet in the basement ceiling in the circuit for the driveway light. The poles on the switch for the driveway light are connected only to the hot and neutral wires from a single romex coming into the box.
The switch for the door light does not have a GFCI in its circuit. The door light's neutral is pigtailed with other neutrals coming into the box (but not with anything wire from the romex for the driveway light).
If I replace both switches with a single switch, is it possible to wire it in a way that won't confuse the GFCI and will be safe? This is the timer switch I'm looking at using:
This switch requires a neutral, line, load, and ground.
Clarification: 1. The two switches are on separate circuit breakers. 2. Both switches are in the same box. It is a 3-gang with one other switch in it as well. 3. The GFCI outlet cuts power to the driveway light when it triggers.
Here is a picture and some explanation. It is crowded in there, but I have labeled the 5 romex cables that enter the box, and the switches.
R1: goes to the driveway light. The driveway light, the GFCI in the basement, and another nearby indoor outlet are all controlled by said GFCI. The neutrals for R2, R3, R4, and R4 are all pigtailed together. R2, R3, R4, and R5 are all on the same breaker.
R2 comes from the basement panel. Its black wire is capped, not connected to anything.
R3 goes to the basement panel, it is on a separate breaker from R1.
R4 goes to the outside door light.
R5 goes to the indoor ceiling light.
R5 is the only W/B/R romex, and the indoor light is wired here as if it is a three-way, but there is only a single switch that controls it. Perhaps this is vestigial. But this switch and light are not involved in my question.
I understand now why I can't combine the two lights into one switch while they are on two different circuit breakers. That makes sense to me. It sounds like one option would be to move one of the lights onto the other's circuit, but I don't know if that would be possible. The driveway light switch with the GFCI circuit is only connected to the one romex, which I have to assume is the hot coming from the GFCI outlet, and the load going to the light. I don't even have access to the neutral for that at the box with the switch. I'd have to run another wire to this already crowded box. Is my reasoning correct?
Here's a drawing of the wiring of the GFCI in the basement ceiling:
Each numbered square is a cable going into the GFCI box.
1: comes from the main panel
2 and 3: One of these goes to the indoor outlet. I have no idea where the other one goes. I mapped out what all the circuit breakers control a few years ago, but I must have missed one thing.
4 and 5: since these are in series, they must be the driveway light and switch for the light. 4 should be the switch, and 5 the light.
One way to go would be to take the front door light off the other circuit and route its cable in series with 4 and 5:
GFCI B --> B Switch W --> B Door light W --> B Driveway Light W --> W GFCI
Maybe this isn't good to run two loads in series? Parallel would be better, but I think the running the wiring for that would be much more difficult. But if doing it in series is dangerous, I don't want to do that.
4th edit, responding to @Harper's comments:
The electrician who put in the driveway lamp also put in the basement ceiling GFCI at the same time, so I have to assume it's required. Of the options Harper presented:
- the deadfront (without an outlet) is probably the most acceptable
- An outlet on the switch plate is not acceptable
- a GFCI breaker could also work
It will be very tight in that box with a deadfront, but maybe this will work. Would the way to implement this be:
- Connect cable 4 to 5 in the basement to make a passthrough, so that R1 at the switch box goes directly to the driveway light. Now the switch box only has one breaker circuit coming in. The basement GFCI does go there anymore.
- Take the hot and neutral feeding the box and split it so it feeds both the switch going to the inside light (R5) and the input of a new deadfront GFCI in the box.
- Output of the deadfront GFCI goes to R1 (driveway light) and R4 (outside door light).
Using a GFCI breaker in the circuit panel would mean a solution similar to the above, except the switch box would be less crowded and everything on that circuit would be on GFCI - this includes 5 lights, 3 outlets and 2 garage door opener motors.
Alternately, if I can find the cable in the basement drop ceiling that goes to the switch box, I can stick a second GFCI outlet there instead of in the switch box or breaker.