water heater

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Old 11-22-00, 09:18 PM
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wiring a small commercial bathroom with only sink and toilet installing 2.5 gallon water heater that operates on 110 volts and comes with a plug so no direct wire necessary-does this need to be on its own circuit or can it be wired into the lights and outlets (there are only 2 outlets 1 light) on the same 20 amp breaker------thanks, josh
 
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Old 11-23-00, 05:51 AM
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Without knowing the amp rating of your water heater, I cannot tell you exactly what you need. I can give you some guidelines. I would install that heater on it's own circuit if the unit is rated for more than 12 amps for a 15 amp general lighting circuit, or more than 16 amps on a 20 amp general lighting circuit. The code guideline is no cord and plug connected equipment shall exceed 80% of the circuit rating where general lighting and/or receptacles are on the same circuit. This changes to 50% of circuit amps for hardwired equipment on a general lighting circuit. Be careful not to exceed total circuit rating with this, in other words don't install your heater on a lighting circuit that covers 400 square feet of office space! If you have one outlet, one light and your new heater, it sounds as if you should be OK.
 
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Old 11-24-00, 09:11 AM
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I mostly agree with the previous reply. I do have a couple of points I thought needed to be touched on.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by s1nuber:
This changes to 50% of circuit amps for hardwired equipment on a general lighting circuit. Be careful not to exceed total circuit rating with this, in other words don't install your heater on a lighting circuit that covers 400 square feet of office space! If you have one outlet, one light and your new heater, it sounds as if you should be OK.[/B]<HR></BLOCKQUOTE>

The question is his term hardwired versus fastened in place.

I agree with the previous post that we can not give you a specific yes or no to your question because you did not include the wattage rating of you water heater. I also agree that I feel you should install a dedictated circuit for this heater. I also agree on a limited basis the statement that you should be ok.

This is where I have a couple of questions. I believe that the NEC says that it is ok if your water heater is less than 50% of your branch circuit rating and if the combined load does not exceed 80% of the rating of that circuit.
However the previous reply stated he guessed your load to be about 12 amps. If the load is indeed 12 amps from your water heater then it is my belief that you must install a new circuit keeping off the branch circuit because this 12 amp load would exceed the 50% limitation of that branch circuits rating.

I suspect that if you will check the NEC the previous reply may have erred in stating the 50% limit is for hard wired equipment. I think he felt that you water heater was allowed over the 50% rating because it was cord and plugged instead of hard wired. I suspect that you should find that the NEC limits any equipment fastened in place, whether cord and plug connected or hardwired, be limited to the 50% max of the rating of that branch circuit, therefore requiring the water heater to be on a dedicated circuit if the water indeed is rated more than 10 amps on a 20 amp rating or 7 1/2 amps on a 15 amp circuit.

In my opinion, in the previous reply, his knowledge shined on this subject. I just believe that the reply was just a bit inaccurate on what the NEC says about utilization equipment [fastened in place] and the limitation of the 50% load allowed.

Hope this helps

Wg
 
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