New Water heater circuit too small

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brother

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Got a new project when they bought a new water heater and they need us to reconnect the circuit. It appears the circuit is too small for this size water heater, (that is in a ceiling most inconvient spot). 3000 watt 120 volt wh. They had a number #12, 20 amp circuit. They claimed it was a the same as before. I told them it appears someone did it wrong from start, . Even without the 125% calculation added in, its still above 20 amps.

Question that was asked, can they just change out the heating elements to smaller wattage ones, and let it go. I believe since it is brand new, it will void the warranty, (they should have just ordered the right one). but it should work. Not sure if it would be a UL listing NEC code issue, since it was manufactured with the higher elements. Is there an NEC violation here?
 
drcampbell

drcampbell

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Location
The Motor City, Michigan USA
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Registered Professional Engineer
NEC violation? Maybe, technically, since there's a 20-amp circuit feeding a device that's labeled 3000 watts.

If you change the element, it'll work ... until the next time.

The water heater label will still say 3000 watts. When this aftermarket 2kW element needs replacing, it'll get replaced with a 3kW element, as specified on the label.

How well would you like to do this job, and what can you get paid for?

At very least, there ought to be a prominent notice that the circuit can support only a 2kW appliance.

Is this a commercial building, with conductors in conduit? The best approach would be changing to #10awg conductors and a 30-amp breaker.
 
T

Tulsa Electrician

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Tulsa
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Electrician
Maybe 3000 w at a higher voltage. Change breaker and element and have the same output as needed.

3000/240=12.5 line to line

Help balance load as well reduce netural load.

May need new to hook direct ( bypass internal switch if applicable) install breaker lock.

Re- identify the grounded conductor at each end.
 
kwired

kwired

Electron manager
Location
NE Nebraska
Tulsa Electrician said:
Maybe 3000 w at a higher voltage. Change breaker and element and have the same output as needed.

3000/240=12.5 line to line

Help balance load as well reduce netural load.

May need new to hook direct ( bypass internal switch if applicable) install breaker lock.

Re- identify the grounded conductor at each end.
Click to expand...
That was my thought when OP said was same as before - 3000 watts but @ 240 volts maybe was what was there before?
 
R

retirede

Senior Member
Location
Illinois
kwired said:
Actually with the continuous load factor that is required it can't be over 1920 watts.

That said I've seen many 2000 watt units on 12 AWG and a 20 amp circuit. I even have one in the bathroom in my shop that never gives me any troubles.
Click to expand...

Are water heaters a continuous load? I can’t imagine one running for 3 hours straight.
 
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hillbilly1

Senior Member
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North Georgia mountains
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Owner/electrical contractor
At least they had the right voltage, I changed one in a Walmart hair salon, plumber put in a 208 volt three phase water heater, old one was 480 volts three phase. They had to come back and change out the elements and controls!
 
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brother

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Location
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drcampbell said:
NEC violation? Maybe, technically, since there's a 20-amp circuit feeding a device that's labeled 3000 watts.

If you change the element, it'll work ... until the next time.

The water heater label will still say 3000 watts. When this aftermarket 2kW element needs replacing, it'll get replaced with a 3kW element, as specified on the label.

How well would you like to do this job, and what can you get paid for?

At very least, there ought to be a prominent notice that the circuit can support only a 2kW appliance.

Is this a commercial building, with conductors in conduit? The best approach would be changing to #10awg conductors and a 30-amp breaker.
Click to expand...
I get paid regardless. I worked for a company that does public work as well. I agree, the mislabeling would have to changed if they asked me to go this route, or better yet, asked the plumber to put in a smaller wattage heating element. He has already filled it full of water, so he might have to drain it. Its in most inconvenient spot, hate it when they put water heaters in a ceiling and tight crawl spaces.

I would just do the power hook up. I was told because it is a new water heater, if they change the element (tamper with) it will void the warranty on it. This is a commecial building and the box and conductors in the conduit are too full feeding other circuits. Looks like there had been some rework over the years and people just did whatever!
 
W

winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research
Customer gets a choice: replace the incorrect water heater, change the element and void the warranty, or change the wiring.

They don't get to use a 12ga circuit at 25A on a 30A breaker. If the conduit is that full, they might not even get to use a 20A breaker.

Jon
 
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