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Hot water heater electrical requirements

I am a little stumped on this one. I am replacing my old electrical hot water heater soon. a 240v breaker in there, pretty sure 30amp, though I haven't checked.

I know my old hot water heater uses a single 4,500w cathode so it is possible it is a 20amp 240v breaker (if such an animal exists).

I am looking at getting a Whirlpool EE3J50RD045V which states that it has two 4,500w cathodes, however in the user's manual it says the electrical hookup is a single 240v 30amp breaker, which only comes out to a max of 7,200w, well below what two 4,500w cathodes would draw. So I am a little confused by this. Is the user's manual wrong and it requires a single 240v 50amp breaker? Or does it use a pair of 4,500w 240v cathodes, but doesn't power either cathode at the full 4,500w?

I am trying to figure out if I need to upgrade my circuit or not, also a little confused by the 4,500 dual cathodes. Thanks.

NEC
Re: Hot water heater electrical requirements
<a href="mailto:[email protected]" rel="nofollow">[email protected]</a> wrote:

I am a little stumped on this one. I am replacing my old electrical hot water heater soon. a 240v breaker in there, pretty sure 30amp, though I haven't checked.

I know my old hot water heater uses a single 4,500w cathode so it is possible it is a 20amp 240v breaker (if such an animal exists).

I am looking at getting a Whirlpool EE3J50RD045V which states that it has two 4,500w cathodes, however in the user's manual it says the electrical hookup is a single 240v 30amp breaker, which only comes out to a max of 7,200w, well below what two 4,500w cathodes would draw. So I am a little confused by this. Is the user's manual wrong and it requires a single 240v 50amp breaker? Or does it use a pair of 4,500w 240v cathodes, but doesn't power either cathode at the full 4,500w?

I am trying to figure out if I need to upgrade my circuit or not, also a little confused by the 4,500 dual cathodes. Thanks.

A while back member Jack made the comment on another WH thread that the two elements are wired such that they cannot be on simultaneously. I raised an eyebrow at that one but he may be right.

Re: Hot water heater electrical requirements

Just follow the manufactuerers directions, dont over think it. A single two pole 30 amp breaker.

NEC
Re: Hot water heater electrical requirements

Yeah, took a look at your owners manual and it is listed at 4500 watts and not 9000. This would tell me the control board only allows one element to be on at any given time.

You should be good to go at 240volts/30amps.

Re: Hot water heater electrical requirements

Okay thanks. I was feeling like I was over thinking it, but seeing it say dual 4500w elements, but only needing a 240v 30amp circuit was worrying me that there was a missprint somewhere.

JLMCDANIEL
Re: Hot water heater electrical requirements

90 % of the time only the lower element is used. If all the hot water is removed from the WH the thermostat for the upper element turns it on and cuts the power to the lower element until the water in the top of the tank heats up. Once the top is heated the upper thermostat shuts off and allows power to the lower unit.
Jack

Ernie_Fergler
Re: Hot water heater electrical requirements
NEC wrote:

Yeah, took a look at your owners manual and it is listed at 4500 watts and not 9000. This would tell me the control board only allows one element to be on at any given time.

You should be good to go at 240volts/30amps.

Methinks that as well. Gee, I sound like Al Micheals of MNF fame with that one.:cool:

Re: Hot water heater electrical requirements
JLMCDANIEL wrote:

90 % of the time only the lower element is used. If all the hot water is removed from the WH the thermostat for the upper element turns it on and cuts the power to the lower element until the water in the top of the tank heats up. Once the top is heated the upper thermostat shuts off and allows power to the lower unit.
Jack

Ahhh makes sense to me. Sounds like a pretty good design feature to speed hot water recovery.

Thanks!
-Matt

Re: Hot water heater electrical requirements

Its common for water heaters to have dual elements. Many can be factory wired for simultanous heating or single element heating. Generally, there is a wiring diagram that shows how the hot water heater can be set-up and the water heater is marked how its set-up at the factory.

JLMCDANIEL
Re: Hot water heater electrical requirements
ohmy wrote:

Its common for water heaters to have dual elements. Many can be factory wired for simultanous heating or single element heating. Generally, there is a wiring diagram that shows how the hot water heater can be set-up and the water heater is marked how its set-up at the factory.

I won't argue your statement, but I'm 68 years old and have never seem a residential water heater set up so both elements can come on simultaneously.
Jack

keith3267
Re: Hot water heater electrical requirements
JLMCDANIEL wrote:

I won't argue your statement, but I'm 68 years old and have never seem a residential water heater set up so both elements can come on simultaneously.
Jack

I think I had one, but each element was only 1250 watts.

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