Number of Conductors After Derateing

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Jim W in Tampa said:
It cant be this easy to get out of afci breakers.I see a great market for a 19 amp and 14 amp breaker,but then why would they want to help us when they make more from selling worthless afci breakers.
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They don't have to, they already make 10 amp breakers we can use, just serve the bedroom with a couple of 10 amp circuits ;)

Roger
 
finhead said:
My question is also a thought problem. Section 240.6 does not recognize 10 amp circuit breakers as a standard OCPD.
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But 1, 3, 6, and 10 Amp fuses are recognized as standard overcurrent devices, so if the derated current is less than 10 Amps you must use 10 Amp fuses instead of breakers.
 
Jim W in Tampa said:
Use # 14 and get even more in it LOL.You make the head and i will put our tugger on it.
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I was an apprentice on a job where we were pulling 60+ 14's in rigid. They only carried 4-20 mA signals.

One in particular was 60+ in a 1 1/2. You're supposed to double the rope back and tie it off to make it easier to put the head on. I wasn't thinking and tied it in a knot around a peice of strut.

If you can picture it, the first way means you can unsecure the rope and pull the wire in. The way I did it means you have to take the head off to untie the knot. At least half a dozen journeyman and 2 angry foremen were there to tell me exactly how dumb that was. Let me tell you, that is a mistake you make ONCE.

The strut came out. Easier to undo it than the head.
 
roger said:
..after using 10 amp breakers you would not have to guard the bedroom circuits with AFCI's.
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This original idea deserves other considerations not mentioned yet.

1) If fixed loads over 5A cannot use these outlets, 10 amp circuits may be impractical for many fixed bedroom appliances, which "shall not exceed 50 percent of the branch-circuit ampere rating." a) Fixed cord & plug, heaters, etc. 210.23(A)(2), b) Window AC's 440.62, c) Park Trailers 552.46(B)(3)(a)

2) Vacuum cleaners over 12A may blow 10A breakers, especially if any shared outlets (same circuit) are used by entertainment electronics, lamps, or home office equipment.

3) Are you sure it won't be inspected?
Installing 10A breakers in panels invites inspectors, ignorant to compatible-design considerations, to harass you with red tags requiring costly time and appeals to prove compliance.
 
Roger,

ramsy said:
This original idea deserves other considerations not mentioned yet.

1) If fixed loads over 5A cannot use these outlets, 10 amp circuits may be impractical for many fixed bedroom appliances, which "shall not exceed 50 percent of the branch-circuit ampere rating." a) Fixed cord & plug, heaters, etc. 210.23(A)(2), b) Window AC's 440.62, c) Park Trailers 552.46(B)(3)(a)
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how many homes will ever have this many conductors bundled that would require this amount of derating? If we were to really use a 10 amp circuit, the code issues you point to would have to be considered in our installation.

ramsy said:
2) Vacuum cleaners over 12A may blow 10A breakers, especially if any shared outlets (same circuit) are used by entertainment electronics, lamps, or home office equipment.
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This would be an end users problem, not a code issue.

ramsy said:
3) Are you sure it won't be inspected?
Installing 10A breakers in panels invites inspectors, ignorant to compatible-design considerations, to harass you with red tags requiring costly time and appeals to prove compliance.
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I don't know if it would be inspected or not, but if I were running this big of a conduit with this many conductors in a single dwelling unit I'd probably have the Local TV News cover the installation. :D

Roger
 
This thread sure took a silly turn. It's not that you have to figure out how to use the derated ampacity, you have to work the other way.

What is the quantity of conductors you need, and the available current needed through each?

What is the wire size necessary, after derating, to carry that current?

Then you determine the conduit size necessary for that quantity of that size.

If you need 20 amps, and have to derate to 35%, you need a conductor individually rated for 57.153 amps, or #6. What size conduit is required for that number of conductors?
 
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