Water heater 29 amps

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M. D. said:
As the temp of the wire increases so does the resistance more resistance equals more heat which adds to the resistance again creating more heat,.. and with this not being sized at 125% it could indeed trip.
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Also the manufacturer rates the elements at a nominal voltage . Sometimes a wattage at 208 and 230 . If you have 240 volts or a little over and subject to power surges, and the breaker is already hot from being borderline it will trip for sure.
 
ItsHot said:
I was doing old apartment upgrades. The exsisting water heaters were 2 element heaters on 2 pole 20a breakers! This was the first time that I had seen this. Put my meter on a couple of panels to check voltage, it averaged around 245v.
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What wire size did they run?

My mother in law has a dryer on a 2 pole 20 amp breaker, it has yet to trip. go figure.
 
jetlag said:
a 4500 watt residential w/h usually reads about 18 amps. Ive never seen a residential w/h you couldn't run on #10 wire.
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Every 4500w water heater I've seen is wired internally with #12, by the way.
 
stickboy1375 said:
What wire size did they run?

My mother in law has a dryer on a 2 pole 20 amp breaker, it has yet to trip. go figure.
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Bet it's a Zinsco or FPE.... :grin: :grin: :grin:


Edited to add: Post #200 Whoooo hooo!!
 
stickboy1375 said:
No, but next best thing. GE :grin:
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Ahh, and the thins too?

Have always wondered how they could possibly build a reliable breaker in such a thin casing...especially in ratings above 20amps.
 
M. D. said:
As the temp of the wire increases so does the resistance more resistance equals more heat which adds to the resistance again creating more heat,.. and with this not being sized at 125% it could indeed trip.
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That resistance is in series with the load,so if anything it will draw even less amps
 
cschmid said:
I believe it would trip under the right circumstances..like if they were taking a shower, doing laundry and running the dishwasher all in lets say an hour were the water heater would run non stop for 90 minutes or so..I believe the extra resistance caused by the extended heating time could cause the breaker to trip..then add in the age of the water heater and the hardness of the water to acerbate the whole scenario..
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HUH?????
Im with Larry.....should not trip
 
What i am saying is ,the resistance of wires goes up with heat.Draw this out and your wires feeding this water heater are in series.As a total your resistance from the wire and heater element will be higher if its hot.That in turn lowers voltage on the elements.End result is lower amps not higher.
 
M. D. said:
As the temp of the wire increases so does the resistance more resistance equals more heat which adds to the resistance again creating more heat,.. and with this not being sized at 125% it could indeed trip.
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OK lets get back to basics.
When resistance increases, voltage stays the same, current flow...........

When resistance increases, voltage decreases, current flow. ..........
 
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