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Jimbo13 09-22-2011 02:58 AM

Installing Electric Water heater
This is my installation plan, Do I have this right?

I've left out a few common sense items and didn't include the plumbing on the heater as I don't have any questions about it.

JoeD 09-22-2011 06:50 AM

Only thing I would change is snap breaker into place before attaching the wires.

gatorfan 09-22-2011 07:57 AM

What size wire does the water heater manual call for (or what current does the name plate specify)? 422.13 says water heaters smaller than 120 gal should be considered continuous load, so if your draw is 25A or more you need to use #8.

Your diagram only shows one hot going to the panel, but since you mention a double-pole breaker I assume you know that you'll actually have two hots (plus neutral and ground).


Jimbo13 09-22-2011 11:53 AM

I'll use the wire the manual calls for when I buy the unit, Reading elsewhere suggested it would most likely be #10 wire.

Jimbo13 09-22-2011 12:56 PM

Thanks, I just been looking at tank-less instant demand heaters and the GPM ratings suggest with my one bathroom dishwasher free home it would suit my needs.

Considering they are 120v do they generally require another breaker put in?

ohmy 09-23-2011 05:38 AM

Yes, you will need a new circuit for a new water heater even a small one. I think water heaters are sized on the number of showers. That is the biggest factor.

120V means the type of voltage. When you say a new breaker your talking about handling load/amperage/available power to run your water heater. On your water heater is a label that says how much power the unit draws. In the national electrical code handbook is a section(s) that tells you what size breaker and wire is required depending on your current draw or required power, etc. Having the right voltage is only half the equation.

ohmy 09-23-2011 05:43 AM

BTW, any plans to have that panel changed? You may want to Google "federal pacific panel" and see what comes up. For fun you can add the words "fire" "lawsuit" "deaths" and "safe."

JoeD 09-23-2011 06:32 AM

If that is an electric tankless then it requires 120 amps. That is not a misprint, 120 amps. Usually it means three double pole 40 amp breakers, six spaces in your panel. If you don't have a minimum of 200 amp serivce and the required breaker slots, then a service upgrade will be required.

nealtw 09-23-2011 09:01 AM

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