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wire size 6 awg and circuit breaker 30 amps to 10kw central heater

wire size 6 awg and circuit breaker 30 amps to 10kw central heater

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Old 12-10-10, 04:47 PM
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wire size 6 awg and circuit breaker 30 amps to 10kw central heater

I need someone help, please

I replaced new AC unit with the heater 10kw (the old one's 5 kw), and it tripped the 30 amps breaker in about 5 minutes after the heater turned on and noticed it draws about 42 amps on the DMM. Could I replace with 50 amps breaker on wire size 6 awg AL? Is it safe? (there is nothing else connected to this circuitry)
 
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Old 12-10-10, 05:46 PM
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The best you can do with #6 aluminum is 40 amp if it is Romex type cable. If this is conduit you may be able to do better if you can replace the wires with copper.
 
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Old 12-10-10, 06:52 PM
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thank you for your help, tolyn Ironhand.

#6 aluminum is multi stranded wire. I could not be able to replace it. Is it safe for 50 amps breaker? 40 amps breaker still tripps because the heater draws 42 amps

Please advise and thank you
 
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Old 12-10-10, 07:15 PM
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A heater is considered a continuous load and the branch circuit to it must be sized to 125% full load. That would work out to 53 amps. That means you need a 60 amp breaker and #6 copper or #4 aluminum.

#6 aluminum is multi stranded wire
Do you mean cable*? If so it needs to be replaced with 6-2 NM-b. If you have conduit pulling stranded wire is not a problem.

I could not be able to replace it.
Give us details and maybe we can help with a way.

*Cable is two or more conductors in the same non-metallic or metallic sheath.
 
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Old 12-10-10, 08:06 PM
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Originally Posted by vuhop2000 View Post
Is it safe for 50 amps breaker?
No. You must install a new cable for this heater. The old cable is not large enough to safety power the heater.
 
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Old 12-15-10, 07:00 PM
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Thank you for your help,
I'll have this cable replaced,
 
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Old 12-15-10, 07:15 PM
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Hi Ray2047

#6 AL cable has 2 conductors feed thru a metal conduit to the control panel installed out side on the back wall, I may have a problem running the cable down to the back wall from the top because the eve of the roof is low.

is there a way you can help, Thank you very much
 
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Old 12-15-10, 08:01 PM
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You really don't need cable in conduit. Why not use the cable to pull THWN individual wires into the conduit. If the conduit isn't continuous between panel and heater you may be able to add boxes to transition to cable.

Or am I misreading and there is no conduit on the back wall or it doesn't extend to somewhere you can reach.
 
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