6 gauge wire

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Old 05-22-04, 06:26 PM
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6 gauge wire

Is it ok to have 60 amp breaker on 6 gauge? 40 ft.
 
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Old 05-22-04, 07:32 PM
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In general, yes, no problem.
 
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Old 05-23-04, 06:50 PM
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That dependson a few things? Is it copper or aluminum,what type of insulation is it? For example type TW & UF {60 deg temp rated} copper is only rated for 55 amps.Type THHN {90 deg} copper has an ampacity of 75 amps.Whereas aluminum type TW & UF {60 deg} has an ampacity of only 40 amps.Type THHN {90 deg} aluminum is rated for 60 amps
 
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Old 05-23-04, 07:37 PM
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I'll tell you I assumed copper. Even the lowest temperature termination is good for 55A, which can be brought to the next higher standard size breaker, 60A.
 
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Old 05-23-04, 08:00 PM
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It's almost always misleading to quote a number from the 90-degree column. Wire never has that ampacity.
 
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Old 05-24-04, 02:40 AM
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JOHNJOHN,

I am going to echo HandyRon's answer. In general, 6ga wire can be used on a 60A breaker.

But there are several caveats to this, so it would really help if you provided more information about what you are doing.

1) In the US, wire this small is usually Copper. In general you _can't_ use 6ga aluminium wire on a 60A breaker.

2) The most common temperature rating that you have to use is the 60C rating. This limits the ampacity of 6ga Copper wire to 55A. If your load is _less_ than 55A, then you are permitted to use a 60A breaker on this 55A wire. But if your load is greater than 55A, then you must use wire with higher ampacity.

2a) Wire with a higher temperature rating, meaning wire that is permitted to get hotter, can carry more current and has a higher ampacity. If you want to do this, all of the wire and all of the connections to the wire need to be rated for the higher temperature. Most loose wire these days is rated for 75C wet or 90C dry, but most circuit breakers and conductor terminations are only rated for 75C. So you could possibly use the 75C rating, in which case the wire has a 65A rating.

2b) If you are talking about NM, NM-B, or UF cable, then you must use the 60C rating of the wire.

3) If the conductors are Aluminium, then the ampacity goes down because Aluminium is a worse conductor than Copper.

-Jon
 
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Old 05-25-04, 07:07 PM
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I'm sorry it was copper 90 deg.
 
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