Individual Water Heater

[augie47]

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 ?

 

[Volta]

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 ?

Nope, unless we can cook with them 210.23(C).

 

[Dennis Alwon]

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 ?

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.

 

[Dennis Alwon]

Good catch-- that may do it

 

[augie47]

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.

 

[Dennis Alwon]

Well I am confused-- does this mean we cannot wire an electric furnace with a 40 or 50 amp circuit in dwelling units???????????

 

[Dennis Alwon]

I had to edit my previous post but I am still confused

 

[augie47]

Dennis, I think 210.23 (general) says loads supplying "two or more", so it would not apply to an individual load.

 

[Volta]

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.

I think so.

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.

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 .

 

[Dennis Alwon]

Got it. Thanks Gus & Volta.

So back to the OP what say you all. I still say yes given the numbers he gave.

 

[augie47]

with 1200 watt units, yes

 

[Volta]

...
So back to the OP what say you all. I still say yes given the numbers he gave.

I'll second that.

 

[Npstewart]

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.

 

[Volta]

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.

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.

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.

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.