Electrical Wiring in the Home/DPC and timer


Hi Bob,
Sorry to bother you again, but you were so helpful the last time.
To refresh, I connected a DPC to my electric water heater and a timer to the DPC. I sent 240v through the 110v coil on the DPC and burnt out the coil. When I had it in my hand I looked at it and itís burnt. Thank you so much for catching that.

The new DPC came in, but the timer did not. I connected the new DPC and decided to try the old timer. It worked!

However, I have a new problem with the way I wired the timer switch. I had a 1-gang box with a two way light switch. I changed it to a 2-gang box, the two way light switch and the countdown timer for the water heater.
I wired the timer as follows.
Green to ground and ground to ground from the two-way and the wall...all the grounds are connected together.
Whites all together (2 from the wall that were already wired together from the two way, I added 1 from the DPC, and 1 from the timer)
Red to black going to the DPC
Black to black on brass screw on the two way

The two way switch is wired as follows
Black on black screw (side 1)
Black on brass screw (side 1)
Red on brass screw opposite side of the two blacks. (side two)
Ground on ground.

It works, but if you turn on the light (two way switch) the timer shuts off. I tried wiring the black from the timer to the black wire black screw, same thing. Black timer to black brass screw, same thing.  I tried wiring it to the red wire brass screw and nothing happened.

The two way runs a light in a very small hallway which we almost never use the light. We can live like this without a problem. However, the world isn't right. Two questions, is it okay to leave it wired like this, and two, is there a way to wire it so the two way switch light works at the same time as the timer, or is it that is just the nature of the way two way switches work?

Thanks again Bob.


It won't work, because you don't have a neutral in the switch box.  All of the wires are hot, and everything is in series.

I'm a little confused about wiring a water heater timer to a lighting circuit.  A water heater is usually 30 amps, and is too much for a lighting circuit.
About Electrical Wiring in the Home
This site answers questions related to home electrical wiring, home wiring, general electrical help,and other electrical questions related to aleternating current (AC). You can find help on the National Electical Code, home electrical issues, wiring electrical outlets, installing lighting, electrical grounding, and general electrical help for do-it-yourself projects not require an electrician. If you do not see your home electrical wiring question answered in this area then please ask your electrical wiring question here

Electrical Wiring in the Home

All Answers

Answers by Expert:

Ask Experts


Bob Sponaugle


Just about any home wiring question. (not appliance repair) I have done all kinds of home wiring for myself, including adding a new breaker box, etc. Please, questions from North America only. Please be specific with details.

©2017 About.com. All rights reserved.