What size protection for an Electric Hot Water Heater at 45kW

[BatmanisWatching1987]

The plumber told me he will be installing a 45kW (208V/3P) Electric Hot Water Heater.

Should I use a 150A or 175A Breaker?

(45kW/ √3) * 208) * 1.25= 156.13A

 

[texie]

You need to see the specs for the heater. Some require multiple branch circuits while others do the required load sub division internally.

 

[tom baker]

I won’t mention, but others will, if you are heating hot water the required KW should be much less.

 

[augie47]

I won’t mention, but others will, if you are heating hot water the required KW should be much less.

couldn't resist, could you

 

[BatmanisWatching1987]

You need to see the specs for the heater. Some require multiple branch circuits while others do the required load sub division internally.

 

[LarryFine]

Should I use a 150A or 175A Breaker?

(45kW/ √3) * 208) * 1.25= 156.13A

Sounds like 175a to me (regardless of incoming water temperature ).

 

[JoeStillman]

I won’t mention, but others will, if you are heating hot water the required KW should be much less.

Sounds like a tankless, on-demand water heater. I object to them whenever I see them.

 

[Dennis Alwon]

If this water heater is more than 120 gallons then you don't need 125% based on 422.13

That means 125 amps and the literature appears to support that.

 

[Dennis Alwon]

Sounds like a tankless, on-demand water heater. I object to them whenever I see them.

Did you see the link--- it is not tankless

 

[JoeStillman]

Did you see the link--- it is not tankless

Oops. Must be a commercial installation.

 

[Dennis Alwon]

Oops. Must be a commercial installation.

3 phase 45kw

 

[david luchini]

The plumber told me he will be installing a 45kW (208V/3P) Electric Hot Water Heater.

Should I use a 150A or 175A Breaker?

(45kW/ √3) * 208) * 1.25= 156.13A

175A minimum per 422.13.

(200A maximum per 422.11(E)).