480v Water Heater

[rtselectric]

Call me confused but does this nameplate info make sense? I have done many water heaters but this one seems off to me. The water heater is 480v 1/3ph 4000w and there are only (2) terminals for line side. Am I overthinking this? Shouldn’t it have listed the voltage at 277 or 208?

 

[qcroanoke]

No. Without seeing the nameplate. 480 is line to line. Not line to neutral

 

[kwired]

Designated as single or three phase isn't out of the ordinary, but should need three line terminals for when configured for three phase operation but would only use two terminals when configured for single phase operation. Would have different current draw for single vs three phase.

 

[Jraef]

Yeah, the only odd thing here is having only the two terminals. Are you sure it says it can be used with 3 phase? The 3 or 1 phase aspect is not unusual because you just reconfigure how the elements are connected. But you can’t feed it 3 phase without the 3rd terminal.

 

[Dennis Alwon]

Call me confused but does this nameplate info make sense? I have done many water heaters but this one seems off to me. The water heater is 480v 1/3ph 4000w and there are only (2) terminals for line side. Am I overthinking this? Shouldn’t it have listed the voltage at 277 or 208?

I can't imagine why they bought a 480V unit for 4000 watts. The only ones I have done were 3 phase 208v and I don't remember the wattage but it was pretty high and fed with 90 amps or so...

 

[roger]

I think it would be similar to this

https://assets.hotwater.com/damroot/Original/10005/100291551.pdf

See pages 5, 6, and 8

 

[rtselectric]

Thanks for the input everyone. I’m all set…..I was over thinking it, as usual!

 

[kwired]

I can't imagine why they bought a 480V unit for 4000 watts. The only ones I have done were 3 phase 208v and I don't remember the wattage but it was pretty high and fed with 90 amps or so...

If there is limited amount of 120/208-240 load being supplied maybe lessening size of transformer needed is desirable?

Could end up allowing just a single phase 3-7.5 kW transformer vs say a 15 or 25 or even needing three phase transformer for items needing those lower voltages?

 

[Frank DuVal]

I can't imagine why they bought a 480V unit for 4000 watts.

Because they were next to a 480 volt panel, and not a 120/208 whatever panel! Dance with the one that brung you as they say.

Sure, not on the floor at Lowes, but readily available from plumbing supply houses.

 

[roger]

I have wired a few 480V water heaters in schools.

 

[hillbilly1]

4 kw is pretty small for a 480 volt water heater. WalMart uses them for tenant water heating, but they are much larger. Replaced one a couple of years ago, the new one had a 250 volt thermostat running a contactor @480 volts. No control transformer. Burnt out the thermostat in about a week. Had a hard time finding the right thermostat, but did find one.