Individual Water Heater

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My error on 422.11(E) thanks Dennis :)
So, for the moment we assume 4500w heaters. The combined load would require a 47 amp circuit, so we install a #8 THHN on a 50 amp breaker with #8s to each heater. Compliant ?
 
augie47 said:
My error on 422.11(E) thanks Dennis :)
So, for the moment we assume 4500w heaters. The combined load would require a 47 amp circuit, so we install a #8 THHN on a 50 amp breaker with #8s to each heater. Compliant ?
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Well, good question. Based on what I read I would say MAYBE :grin:. It appears once we get over 48 amps then things change. It seems like things change once we need OCPD greater than 60.

I see two heater together with 4500 watts no different than one element at 9000 watts. This appears to be compliant based on 422.11. What I don't like is if one heaters thermostat goes bad then the 4500 element has an OCPD greater than 150 percent.
 
Good point Volta !
If these were in other than dwelling units, permissible ?

In other than dwelling units, such circuits shall be permitted to supply fixed lighting units with heavy-duty lampholders, infrared heating units, or other utilization equipment.
 
Well I am confused-- does this mean we cannot wire an electric furnace with a 40 or 50 amp circuit in dwelling units???????????
 
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Dennis, I think 210.23 (general) says loads supplying "two or more", so it would not apply to an individual load.
 
augie47 said:
Good point Volta !
If these were in other than dwelling units, permissible ?

In other than dwelling units, such circuits shall be permitted to supply fixed lighting units with heavy-duty lampholders, infrared heating units, or other utilization equipment.
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I think so.
Dennis Alwon said:
Well I am confused-- does this mean we cannot wire an electric furnace with a 40 or 50 amp circuit in welling units??????????? I think this is referring to fixed lighting with these other equipment.
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Just that we cannot put more than one on a branch-circuit 210.23.

I'll edit to say that threw me for a couple of minutes too, and I had to retype it all when I saw what it said :).
 
Just a small point, even if it was allowed by the NEC to connect more then one to a circuit , doesen't mean the manufacturer would allow it, meaning the warranty would be voided. Also, the only 1200 watt heaters I heard of would be for a single sink, or a his/her sink where you have a small tank heater that looks like a instant hot heater, they are typically 3 gallons. In my opinion, more then one heater would not be protected if it was on another circuit. Also, remember if it uses more then 80% of that circuit, the circuit should be dedicated for that appliance load.
 
Npstewart said:
Just a small point, even if it was allowed by the NEC to connect more then one to a circuit , doesen't mean the manufacturer would allow it, meaning the warranty would be voided.
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Ok, if the manufacturer states that. But why would they?
Also, the only 1200 watt heaters I heard of would be for a single sink, or a his/her sink where you have a small tank heater that looks like a instant hot heater, they are typically 3 gallons. In my opinion, more then one heater would not be protected if it was on another circuit.
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Assuming you meant 'not be protected if it was with another on the same circuit', why not?
Also, remember if it uses more then 80% of that circuit, the circuit should be dedicated for that appliance load.
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If cord-and-plug connected, and not fastened in place 210.23(A)(1).

If this is connected to the plumbing, it is difficult to imagine that it is not supposed to be fastened in place.
 
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