Water Heater Control

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hillbilly

Senior Member
Hi Guys.

I've got a quick question.

Garage apartment next to main residence.
For use by occasional visitors.

Breaker panel and water heater are downstairs in garage and within sight of each other.

Customer wants to be able to turn the water heater on and off from the upstairs apartment.
This is so a visitor doesn't have to enter the garage to turn the heater on when they arrive, and are able to turn the heater off when they leave.
Strictly a energy saving measure.

Residential water heater 3.5KW, 240V/1.

I plan on mounting a single pole 20A switch upstairs and use it to break one leg of the 240 to the heater.
This would leave one leg of the circuit to the heater hot at all times.
I think that since the breaker for the heater is about 25 feet away and visible from the heater that this will be OK.

Sound alright?

Thanks in advance.
steve
 
Yea, I know I could do that....but.....:)

If I break one leg, I'll only have to make one pull of 12/2NM thru the floor and wall up to the switch.
If I use a 2 pole switch, I'll have pull two cables.

Space is severely limited, and pulling two cables will be a PITA.

So......If my original idea is OK, which I believe it is....it will be a lot less aggravation, and believe me, this winter has me aggravated enough already.:roll:

steve
 
I think that Steve knows that switching both legs is the better way to do it but is his method actually prohibited?
 
Steve I believe your method is valid as long as there is a disconnect insight of the heater. My understanding is that the breaker will take care of that requirement.

Of course, once that water heater gets changed out there goes the whole wiring job. I would up sell that now, if possible
 
As long as it had the required disconnect within sight I see no reason why not. I may be missing something as usal.....
 
Cow said:
If you wanted to go that far, you could then mount a small 240v-24v transformer and run bell/thermostat wire to a switch.
Click to expand...

I have two concerns,

The saftey of a person who might think that it is ok to work in the water heater because
the switch is off. The excuse of 'they should not be in there' is not good enough.

Second, with an open voltage of 240vac and a load of 3500 watts, I don't think the switch
is going to last, ok get a 30a heavy duty switch, well now the contactor is not that far out
there after all.
 
Dennis Alwon said:
Why would you need this? If the op is breaker only one side of the 240v circuit why would the rating need to be more than 125v or whatever a SP is rated.
Click to expand...

See 404.14 (b) I would say the switch is going to see 240 volts. Plus if it switches under load it will see a voltage that is somewhat higher. I can not give you eng. data to support this. Maybe some of the engineers can.
 
I recommend a 2p contactor, too, but with a twist: 3-way switching so it can be controlled at either end.
 
dbuckley said:
I say small 2P contactor too.

Although (as far as I know) a single pole switching device is fine, dandy and legit, it just doesn't feel right to switch only one pole of a two hots feed...
Click to expand...

Why not? That's what the water heater does, leaving both the upper and lower elements 1/2 live at all times.
 
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