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Old 07-19-2014, 10:32 AM   #46
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That is true and a great explanation by Mike and crew ... my view is the feeder is terminating on the ocpd or fused disconnect ... there are no tap conductors. Once you install the ocpd or fused disconnect terminated directly to the feeder conductors the tap rules no longer apply.

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Old 07-19-2014, 04:01 PM   #47
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In a hermetically sealed motor application, the breaker we supply only provides ground fault and short circuit protection, the motor itself contains overloads that protect the conductors, the manufacture supplies the calculations on the nameplate, why do you think you can run #12 awg supplied by a 30 amp circuit breaker?
I know what an internal over load does. And have seen more then one set of wires over heated on an A/C. And I am talking about the wiring from the panel box breaker, not the wires inside the A/C only.

To answer your question. Because the starting amp draw is only for a few seconds at most.
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Old 07-19-2014, 07:46 PM   #48
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Ok Cletis time to shoot straight your continuing to dig a deeper and deeper hole

Though I find nothing wrong with posing hypothetical installations to improve ones understanding of code and wiring configurations but it is a little disingenuous to not be up front about it.
Welcome to the friendly world of Cletis. He is a very smart individual and just likes to pull chains.

1. This job NEVER existed
2. This job never existed.
3. This job never existed
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[ame]http://www.youtube.com/watch?v=4xfYfgpjtws[/ame]

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Old 07-19-2014, 08:06 PM   #49
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I know what an internal over load does. And have seen more then one set of wires over heated on an A/C. And I am talking about the wiring from the panel box breaker, not the wires inside the A/C only.

To answer your question. Because the starting amp draw is only for a few seconds at most.


FWIW, I have seen the breaker trip before the overload many times when a condenser fan stalls. IMO, (I know code allows it) but the overloads in compressors are not the same as a good ole breaker. Separate mounted commercial overloads are held to higher standards from experience.
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Old 07-19-2014, 10:00 PM   #50
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I know what an internal over load does. And have seen more then one set of wires over heated on an A/C. And I am talking about the wiring from the panel box breaker, not the wires inside the A/C only. To answer your question. Because the starting amp draw is only for a few seconds at most.

I have no idea what you are suggesting, but if you have come across burnt conductors, I'm going with loose connections.
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Old 07-19-2014, 10:04 PM   #51
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FWIW, I have seen the breaker trip before the overload many times when a condenser fan stalls. IMO, (I know code allows it) but the overloads in compressors are not the same as a good ole breaker. Separate mounted commercial overloads are held to higher standards from experience.
Seriously? Because we have all the proper testing equipment that UL has.... :-/
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Old 07-19-2014, 10:37 PM   #52
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Seriously? Because we have all the proper testing equipment that UL has.... :-/
That's what Ive seen. Tripped breaker on AC. Reset it compressor starts fan motor doesn't turn. HVAC tech makes the diagnosis of failed condenser fan motor. Doesn't happen all the time but I have seen it.
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Old 07-19-2014, 10:43 PM   #53
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Im going to re-read the code section again, but If I remember right if you have fuses in the exterior disconnect breaker must match the wire size.
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Old 07-20-2014, 04:20 AM   #54
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I have no idea what you are suggesting, but if you have come across burnt conductors, I'm going with loose connections.
No loose connections. Compressor FLA of 15.8, but drawing 17 amps, plus the condenser fan drawing 1.2 amps for 6 plus hours. Tends to over heat a 12 gauge wire.

The internal over load of an A/C compressor is cooled by the returning refrigerant, and doesn't trip just because the compressor is drawing 10 to 15% higher amperage then it should.
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Old 07-20-2014, 08:59 AM   #55
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No loose connections. Compressor FLA of 15.8, but drawing 17 amps, plus the condenser fan drawing 1.2 amps for 6 plus hours. Tends to over heat a 12 gauge wire. The internal over load of an A/C compressor is cooled by the returning refrigerant, and doesn't trip just because the compressor is drawing 10 to 15% higher amperage then it should.
18.2 amps will not overheat #12 AWG, #12 is rated for 25 amps, you could run that continuously and never have an issue, also, the NEC already includes 125% to the conductors for AC units.
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Old 07-20-2014, 09:08 AM   #56
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Im going to re-read the code section again, but If I remember right if you have fuses in the exterior disconnect breaker must match the wire size.
that is because it is a feeder. Look in article 215. And article 100 for feeders.
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Old 07-20-2014, 09:09 AM   #57
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18.2 amps will not overheat #12 AWG, #12 is rated for 25 amps, you could run that continuously and never have an issue, also, the NEC already includes 125% to the conductors for AC units.

If the unit is wired with NM it might be an issue since NM is restricted to 60*C. However I agree, there should not be any burned up connections at 18 amps since the individual conductors are rated 90*C terminals 75*C. Both within limits.
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Old 07-20-2014, 09:10 AM   #58
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that is because it is a feeder. Look in article 215. And article 100 for feeders.
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Old 07-20-2014, 10:23 AM   #59
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18.2 amps will not overheat #12 AWG, #12 is rated for 25 amps, you could run that continuously and never have an issue, also, the NEC already includes 125% to the conductors for AC units.
Guess you don't do a lot of A/C service calls.

The ones I saw were older romex/NM, back before they used Yellow for the sheathing.
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Old 07-20-2014, 10:25 AM   #60
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If the unit is wired with NM it might be an issue since NM is restricted to 60*C. However I agree, there should not be any burned up connections at 18 amps since the individual conductors are rated 90*C terminals 75*C. Both within limits.
They weren't burnt up. They were discolored/browning. Other NM in the same panel box were not discolored or browning.

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