water heater

Status
Not open for further replies.
Z

z-men

Member
Location
Michigan
I'm doing a job at a healthcare facilitie.I have to install a circuit for a 30 gallon water heater.The only info on the name plate is 2000 watts 120 volts.To find the wire size I divide 2000 watts by 120 volts and get 16.6 amps.I times this by 125% and get 20.8 amps which tells me I must use a # 10 wire.

I was looking in one of my workbooks and it said I could use a #12 wire from the 60 degree columb which is 25 amps for this circuit because at the bottom of table 310.16 at the daggar 240.4(D)does not apply to appliance circuits.Could I have run a #12 wire and be legal in this case?
 
Re: water heater

code book in truck,but that 25 amps is for motors if im correct.I believe i would use 10-2 with 25 breaker.Seems strange they used a 120 instead of 240 element ,but your stuck with it.
Do we need to rate this at 125% ? will it run 3 hours

[ January 08, 2004, 06:22 AM: Message edited by: jimwalker ]
 
Re: water heater

Ya Jimwalker.I figured they would use 240 volts for the water heater so I roughed-n with 12/2 mc cable.Then when the water heater was installed it was 120 volts. 422.13 says a water heater 120- gallons or less shall have a rating not less than 125% of the name plate.I think I read some place that water heaters are considered a continious load.I used #10 wire anyway.
 
Re: water heater

A 120 gallon water heater with a 2000 Watt element is almost worthless.

A standard 55 gallon heater has a 4500 Watt element.

Check with the plumbing contractor to be sure about this equipment. I never heard of a 120 volt heater of that size. Maybe 1.2 gallons, but not 120.
 
Re: water heater

It is just flat crazy to wire them on 120.No idea why they would do this unless plumber got a discount on this seldom used heater.Some mobile homes use them.Other than it saves i pole of a breaker or if you only have 120 there is no point to use it.
I have seen them little under the sing ones( 1 or 2 gal) maybe 1500 watts.Enough to wash hands.

[ January 08, 2004, 05:43 PM: Message edited by: jimwalker ]
 
Re: water heater

Excuse my first post, my byfocals showed 120 gallon heater not 30. but a 30 is a lot to heat with 120 volts.
 
Re: water heater

I agree with you guys about the voltage of the water heater.That is what they wanted and that's what I wired up.The water heater is under a sink in a breakroom the only water it heats is for the sink.I would have instlled a little more expensive but more efficent as use water heater.
 
Re: water heater

Then they might have selected it because of size.If there happy and you got paid i see no problem.Small heaters do sometimes come in 120
 
Re: water heater

This is why I made this post.I wired the water heater thinking it would be 240 volts so I stubbed a #12 mc cable under the counter top.When I got to the finish I looked at the name plate and low and behold it was 2000 watt 120 volts.When I calculated it out I came up with 20.8 amps I was hoping that 240.4(D)at the bottom of 310.16 didn't apply.What I did was run a new #10 wire.It may have been cheeper to install a 240 volt thermostat.I met the inspector at the job for inspection and he never even looked at the water heater circuit.
 
Re: water heater

I know this sounds wrong and roger and bob will yell at me :( .But being that it was to be used just for a sink i believe i would have just left it alone on a 20 amp breaker.Really think it won't run anything near 3 hours.This is all over an extra 80 watts

[ January 10, 2004, 09:51 PM: Message edited by: jimwalker ]
 
Re: water heater

Originally posted by jimwalker:
I know this sounds wrong and roger and bob will yell at me :( .But being that it was to be used just for a sink i believe i would have just left it alone on a 20 amp breaker.Really think it won't run anything near 3 hours.This is all over an extra 80 watts
Click to expand...
No I won't yell, I would not hire you either.

Sounds like you get the pay you deserve.

[ January 10, 2004, 09:54 PM: Message edited by: iwire ]
 
Status
Not open for further replies.
Top