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?

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

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.

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.

Was the amperage draw checked for each element? Was this an old breaker?

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.

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.

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

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

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

johnd24: You state that the H2O heater is on a geothermal sys. The accepted method with geo is two H2O’s, not one large one. The H2O’s are connected in series with the first H2O connected to the geo preheat with NO ELECTRIC CONNECTION to the unit. The second H2O is connected to power. My system has two 42 gallon H2O’s connected as indicated on system one and a 30 gallon storage only on system 2.
Rowdy

I have just installed a John Wood 5500 watt water heater. It runs non-simultaneous operation, only one heater at any time. The owner manual for this electric water heater recommended a 35 amp fuses or circuit breaker for 208 or 240volts. Now the question? #8 wire with a 35amp breaker. If you calulate the load a 30amp breaker with #10 wire should work but the manufacturer recommeded 35amps.