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#23498 - 03/19/03 05:33 PM 80 gallon hot water tank
johnd24 Offline
Member
Registered: 07/11/01
Posts: 62
80 gallon hot water tank with upper and lower elements of 5500 watts at 240 volt single phase.Would a 40 amp circuit on # 8's be sufficient?
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#23499 - 03/19/03 05:46 PM Re: 80 gallon hot water tank
Crowbar Offline
Member
Registered: 01/13/03
Posts: 33
Loc: Pittsburgh, PA,USA
If both elements are capable of heating at the same time I would see a 11kw load at 46 amps. That would require a 60 A circuit with #4's. I can't remember offhand (I don't deal with type of install at the mill) if you can use a 30A circuit IF its connected for only ONE element to heat at once. Anyone feel free to correct me as its been awhile.


Rich
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#23500 - 03/19/03 06:00 PM Re: 80 gallon hot water tank
iwire Offline
Moderator
Registered: 01/05/03
Posts: 4391
Loc: North Attleboro, MA USA
I come up with 23 amps so you could use a 30 amp circuit as Crowbar said.

I have never seen a water heater use both top and bottom elements at the same time, you should make sure of this on your unit.
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Bob Badger
Construction & Maintenance Electrician
Massachusetts
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#23501 - 03/19/03 06:11 PM Re: 80 gallon hot water tank
johnd24 Offline
Member
Registered: 07/11/01
Posts: 62
Its on a 30 amp circuit now but breaker is tripping after some time.22.9 amps i thought that would be good at 30 amp circuit myself...hmmm.
Also its hooked up in conjunction to a geothermal so i thought that it would not require much on time since its water lines are connected to the geothermal heat.I thought the water would be warmer and not take much time to heat up.
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#23502 - 03/19/03 06:21 PM Re: 80 gallon hot water tank
stamcon Offline
Member
Registered: 03/24/01
Posts: 329
Loc: So San Francisco CA
Was the amperage draw checked for each element? Was this an old breaker?
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#23503 - 03/19/03 06:22 PM Re: 80 gallon hot water tank
iwire Offline
Moderator
Registered: 01/05/03
Posts: 4391
Loc: North Attleboro, MA USA
If you are sure it tripped at 22.9 amps, I would look for signs of heating at the bus where it attaches to the breaker..

Also I would try a another 2p 30, to see if the breaker is junk.
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Bob Badger
Construction & Maintenance Electrician
Massachusetts
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#23504 - 03/19/03 06:33 PM Re: 80 gallon hot water tank
johnd24 Offline
Member
Registered: 07/11/01
Posts: 62
Its a new home that was completed in july of 2002.I will change the cutlar hammer ch 230 breaker.
But would both upper and lower elements turn on at the same time ? I didnt think so.
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#23505 - 03/19/03 07:47 PM Re: 80 gallon hot water tank
frenchelectrican Offline
Member
Registered: 02/06/03
Posts: 939
Loc: Wi/ Paris France { France for ...
i really advise to check the upper themroast to check the connection or wiring digram to see what it is setup and most WH are set up with ONE element running at time never both unless see the junction box come with very hevey wire like # 6 or 4 gauge wire but majorty of them use either 12 or 10 AWG there( most use 12) but VERY few WH have both hook up at the same time that is restricted to commercal appiactions i allready deal with 3 ph units so kinda instering to know

merci marc
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Pas de problme,il marche n'est-ce pas?"(No problem, it works doesn't it?)

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#23506 - 03/19/03 07:59 PM Re: 80 gallon hot water tank
johnd24 Offline
Member
Registered: 07/11/01
Posts: 62
Thanks guys i think its probably just a bad breaker.I'll find out when i check it out on saturday..Thanks again as usuall this is a great forum. Thanks
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#23507 - 03/19/03 08:36 PM Re: 80 gallon hot water tank
Bjarney Offline
Moderator
Registered: 04/10/02
Posts: 2527
Loc: West-Southern Inner-Northeast ...
Typically one element has a double-throw thermostat that is intended to power one element first and then switch to the other element when one end of the tank is warm. There is a remote chance that the double-throw thermostat has failed {or been reconfigured} and is allowing both elements to operate together.

See diagram A6 at http://www.hotwater.com/PDFSpecSheets/A7070.pdf
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