Electric water heater off/on switch

Old 12-24-03, 02:43 PM
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Electric water heater off/on switch

Have a 40-gallon electric water heater in my shop which I only use for occasional showers. I currently use the double-20 breaker to turn it on and off as needed. I figure this will cause pre-mature breaker falure and would like to add some sort of in-line switch to accomplish the same thing. The circuit leaves the main panel and goes to a junction box a few feet from the heater; then #12 travels through plastic flex to the heater. Any suggestions are greatly appreciated.

Old 12-24-03, 03:53 PM
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One thing I would recommend is rewiring it with 10/2 NM or #10 in your conduit and a double pole 30 amp breaker. More than likely this unit has 4500 watt elements and requires a 30 amp circuit.

Most breakers can handle occassional turning on & off. Like once or twice a week for a very long time. I doubt you will diminish the life of the breaker by much.
There are also breakers labeled "SWD". These are designed to be used as switches and can be turned on and off several times a day.
Old 12-24-03, 08:21 PM
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Thanks Speedy

I rechecked after reading your post and it is a double 30 breaker, and no doubt #10 wire. That's what happens when I rely upon a worn-out memory. I probably turn the breaker on and off less than 40-50 times a year. I priced new breakers once [ square D QO ], and they were very reasonable. I just have never replaced a breaker before, and am not sure if it is something I can do myself. I hope to soon get an air compressor and it seems the better [quieter] ones are all 220. I have a main breaker to turn off, so I may consider trying it myself [ after consulting this forum first].

Thanks again,
Old 12-25-03, 07:36 AM
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You could install a double pole switch in the junction box. Use a double pole switch to switch both sides of the 240 volt.
Old 12-26-03, 09:30 AM
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It's easier to change a breaker than it is to install a double pole 30A switch. But as joed stated, you could put a switch in the J-box. I'm assuming the box has enough cubic-inch capacity to handle all of the #10AWG conductors plus the switch. Depending upon the type of junction box, you may need a "special" switch cover - i.e. if the box is a square metal box you will need a "raised" switch cover.

By code, you need to have a "service disconnect switch" available for the water heater. Your circuit breaker will fit that definition - if it is within site of the heater. I wouldn't worry about installing a switch if that is the case, but would if the breaker cannot be seen from the heater. Although extremely slight, there is always the possibility that someone could turn the breaker on, unbeknownst to someone servicing the water heater if the breaker cannot be seen from the heater.

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