Double gang switches to dimmers

kahnman · Mar 12, 2021

New here so thanks in advance for the help. I'm an architect (definitely not an electrician) struggling through what I thought would be a fairly straightforward replacement of two ON/OFF switches in my 1960s home. One of the switches controls an exterior flood light and I would like to replace it with a Honeywell programmable switch for automated on/off at sunrise/sunset. The other switch controls an LED light fixture in the kitchen so I would like to install a dimmer.

The Honeywell switch has a line wire, load wire, ground wire, and a neutral wire. The dimmer has a line, load, and ground.

When I opened up the junction box, it appears that all of the neutral wires are joined together (no wire nut, just twisted together and taped). There is no ground, and then there are the hot wires currently wired to the switch.

My questions are:

Can I install these devices without the ground wire connected?
Do I need to determine which of the black wires on the existing switches is the load vs line or can I wire them to the dimmer either way?
I assume the current wiring of the neutral wires is not correct - what is the proper configuration and how does the neutral for the Honeywell switch get wired into the existing neutral wires.

Any help would be greatly appreciated.

littlespark · Mar 12, 2021

Sorry to say, but that looks a frickin mess. That may be normal, I don’t know.

@Megawatt is our American expert and will advise further.

In my limited capacity, I would say the neutral will need another length added to the joint there, and a wire nut to hold it all. This neutral then goes onto the switch where required.
Also, in the uk we have to match the dimmer to the LED light... not every dimmer works.

not sure of rules again concerning ground wires, as the switch would be linked to the box via the screws, but need clarification if the ground wire would be needed.

if you have a voltage tester you could determine which is line v load but at the moment it’s guesswork.
Again, with electronic dimmers for LED, it might not work the other way round.

Maji236 · Mar 13, 2021

kahnman said:
New here so thanks in advance for the help. I'm an architect (definitely not an electrician) struggling through what I thought would be a fairly straightforward replacement of two ON/OFF switches in my 1960s home. One of the switches controls an exterior flood light and I would like to replace it with a Honeywell programmable switch for automated on/off at sunrise/sunset. The other switch controls an LED light fixture in the kitchen so I would like to install a dimmer.

The Honeywell switch has a line wire, load wire, ground wire, and a neutral wire. The dimmer has a line, load, and ground.

When I opened up the junction box, it appears that all of the neutral wires are joined together (no wire nut, just twisted together and taped). There is no ground, and then there are the hot wires currently wired to the switch.

My questions are:

Can I install these devices without the ground wire connected?

Do I need to determine which of the black wires on the existing switches is the load vs line or can I wire them to the dimmer either way?

I assume the current wiring of the neutral wires is not correct - what is the proper configuration and how does the neutral for the Honeywell switch get wired into the existing neutral wires.

Any help would be greatly appreciated.

Can I install these devices without the ground wire connected? I don't see why not, cap them off with a wire nut.
Turn breaker off before working on this.

The Honeywell: Line wire goes to blacks currently joined together. Eliminate the one going to the old switch. Load wire goes to other black going to old switch. Neutral will have to go to the rest of them, ALL together. Use appropriate wire connectors for ALL joints, like Wire Nuts (I prefer Ideal brand), probably need a big gray for neutrals.

Dimmer: Line wire goes to blacks currently joined together. Eliminate the one going to the old switch. Load wire goes to other black going to old switch.

Also, as Littlespark mentioned, do check the light can be used with a dimmer.

Be safe

Megawatt · Mar 17, 2021

kahnman said:
New here so thanks in advance for the help. I'm an architect (definitely not an electrician) struggling through what I thought would be a fairly straightforward replacement of two ON/OFF switches in my 1960s home. One of the switches controls an exterior flood light and I would like to replace it with a Honeywell programmable switch for automated on/off at sunrise/sunset. The other switch controls an LED light fixture in the kitchen so I would like to install a dimmer.

The Honeywell switch has a line wire, load wire, ground wire, and a neutral wire. The dimmer has a line, load, and ground.

When I opened up the junction box, it appears that all of the neutral wires are joined together (no wire nut, just twisted together and taped). There is no ground, and then there are the hot wires currently wired to the switch.

My questions are:

Can I install these devices without the ground wire connected?

Do I need to determine which of the black wires on the existing switches is the load vs line or can I wire them to the dimmer either way?

I assume the current wiring of the neutral wires is not correct - what is the proper configuration and how does the neutral for the Honeywell switch get wired into the existing neutral wires.

Any help would be greatly appreciated.

Since that circuit has no ground you need to replace the breaker to a GFCI breaker

kahnman · Mar 29, 2021

Thanks for the help everyone - I finally had a chance to give it another go over the weekend and was able to get the Honeywell switch wired up and working. I also got the dimmer hooked up but turns out the fixture is not dimmable so it just started flashing. Next time I will know to check the fixture first. Thanks again!