Disconnect means for 108 KW instant electric water heater

[white stallion]

The NEC does not make reference to instant type electric water heaters. Can circuit breaker with lock be used as the disconnecting means?

 

[ceb58]

The NEC does not make reference to instant type electric water heaters. Can circuit breaker with lock be used as the disconnecting means?

Look at 422.30 and 422.31B

 

[augie47]

IMO, it would be covered by Art 422.
I would make note of 422.11(F)(1) and 422.31

 

[Little Bill]

The NEC does not make reference to instant type electric water heaters. Can circuit breaker with lock be used as the disconnecting means?

Title of your post 108kw, 108000/240=450A, really?:roll:

 

[Mgraw]

Don't know if they make 240v 1ph that big but they do make 108kw 480/277v 3ph.

 

[iwire]

Title of your post 108kw, 108000/240=450A, really?:roll:

I think most of us assume residential when we here instant water heaters but they are commercial as well.

108000/208/1.73=300A
108000/480/1.73=130A

http://www.hotwaterheater.com/c108kw.html

 

[Little Bill]

I think most of us assume residential when we here instant water heaters but they are commercial as well.

108000/208/1.73=300A
108000/480/1.73=130A

http://www.hotwaterheater.com/c108kw.html

Since the OP said single PH, I didn't figure for 3PH.

 

[stevebea]

Since the OP said single PH, I didn't figure for 3PH.

OP dosen't state single phase.

 

[white stallion]

The instant type water heater is 108KW at 277/480V, 3ph, 4W. The water heater is for a emergency shower in a warehouse application. Prefer not having a disconnect switch next to emergency shower.

 

[ceb58]

The instant type water heater is 108KW at 277/480V, 3ph, 4W. The water heater is for a emergency shower in a warehouse application. Prefer not having a disconnect switch next to emergency shower.

Depending on the layout of the room the disco. would not necessarily have to be next to the shower. 422.31B states with in sight. Art. 100 definitions list this as visible and within 50ft