Amperage

kurmudgeonDecember 6, 2009

I'm wiring up some baseboard heaters using 12 ga cable. I have been told that 12 ga cable won't safely take

more than 16 Amps....

I have also been told that 12 ga cable on a 25 amp breaker

is fine for 4800 watt baseboard heaters....20 amps

Which is correct.

Thank you

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hexus

#12 AWG can only be used with a maximum circuit breaker of 20 amps. Whoever told you 25 is WRONG.
As for the 16 amps. 16 is 80% of 20. You can only load a circuit to a maximum of 80% of the over current protection rating.

if you have a 4800 watt heater using 240 volts that comes to 20 amps. you HAVE to pull #10 AWG to it and use a 30 amp breaker.

    Bookmark   December 6, 2009 at 8:19PM
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kurmudgeon

hexus..our code (Canada) says they have changed the rules allowing higher rated breakers to make greater loading possible. Allowing a 25 amp breaker for 4800 watts.
Why they allow this I don't know.

Would you suggest I ignore the code, if I use 12 ga cable, and go with 20 amp breakers loading only to 16 amps?

    Bookmark   December 6, 2009 at 8:34PM
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petey_racer

Just some clarification:

"#12 AWG can only be used with a maximum circuit breaker of 20 amps. Whoever told you 25 is WRONG."

There ARE some instances where #12 can be on a 25A breaker, but they do not apply here.

"As for the 16 amps. 16 is 80% of 20. You can only load a circuit to a maximum of 80% of the over current protection rating."

This is not true in most instances. You certainly CAN load a circuit to 100%.
Continuous loads though, or those considered continuous loads such as electric heat, DO have to be kept to 80%.

That said, I am not familiar with the Canadian code on this so I won't comment further on that.

    Bookmark   December 6, 2009 at 8:46PM
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hexus

I have no clue on Canadian codes. My mistake I assumed you were in the states.

    Bookmark   December 6, 2009 at 8:47PM
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kurmudgeon

I don't know why they changed the code..which used to be the same as yours in this case but I think i'm going to go with your advice...
Our code seems a little too liberal for me.
Thanks for the responses...appreciated

    Bookmark   December 6, 2009 at 9:00PM
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