conductor Ampacities & terminal temps

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cwain

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I understand the requirements of Art. 110.14 but I have been studying MIke Holts Understandind the NEC and have seen different examples , for instance on conductor ampacity on a three phase motor the book used 60 C column in a few examples and in other examples used 75C column and none of the examples specified the terminal temps. I have been told on motors and equipment to always use 75c column if it didnt say the temps. Thanks for any and all advise.
 
IMO, if the terminals are not given then you should use 60C for circuits rated 100 amps or less and 75C for circuits above 100 amps--- art. 110.14(C)(1)
 
one is in illustration 240-9 and one is in240-10 both of these use 60c I will be looking for the ones that use 75c and I think I seen a Authers comment that said use 75c for most equipment but I cant find it either but will keep looking. Maybe I just thought I seen it.
 
From Card AALZ UL 2009+ White Book
Distribution and Control Equipment Terminations​
Most terminals are suitable for use only with copper wire. Where aluminum
or copper-clad aluminum wire can or shall be used (some crimp terminals
may be Listed only for aluminum wire), there is marking to indicate
this. Such marking is required to be independent of any marking on terminal
connectors, such as on a wiring diagram or other visible location. The
marking may be in an abbreviated form, such as ??AL-CU.??
Except as noted in the following paragraphs or in the general Guide Information
for some product categories, the termination provisions are based on
the use of 60?C ampacities for wire size Nos. 14-1 AWG, and 75?C ampacities
for wire size Nos. 1/0 AWG and larger, as specified in Table 310.16 of
the NEC.
Some distribution and control equipment is marked to indicate the
required temperature rating of each field-installed conductor. If the equipment,
normally intended for connection by wire sizes within the range 14-1
AWG, is marked ??75C?? or ??60/75C,?? it is intended that 75?C insulated wire
may be used at full 75?C ampacity. Where the connection is made to a circuit
breaker or switch within the equipment, such a circuit breaker or
switch must also be marked for the temperature rating of the conductor.
A 75?C conductor temperature marking on a circuit breaker or switch normally
intended for wire sizes 14-1 AWG does not in itself indicate that 75?C
insulated wire can be used unless 1) the circuit breaker or switch is used by
itself, such as in a separate enclosure, or 2) the equipment in which the circuit
breaker or switch is installed is also so marked.
A 75 or 90?C temperature marking on a terminal (e.g., AL7, CU7AL,
AL7CU or AL9, CU9AL, AL9CU) does not in itself indicate that 75 or 90?C
insulated wire can be used unless the equipment in which the terminals are
installed is marked for 75 or 90?C.
Higher temperature rated conductors than specified may be used if the
size is based on the above statements.​
Copper-clad Aluminum Conductors​
​
​
​
​
? Copper-clad aluminum conductors​

 
Here is one of the questions:

Question: What size branch-circuit overcurrent device is required for an air conditioner (18A) when the nameplate indicates the minimum circuit ampacity is 23A, with maximum overcurrent protection of 40A?

(a) 12 AWG, 40 A protection
(b) 12 AWG, 50 A protection
(c) 12 AWG, 60A protection
(d) 12 AWG, 70A protection
Click to expand...


Since no conductor information, other than size, is given I agree with Dennis that you would use the parameters of 110.14(C)(1).
 
I am redoing Charlie's post simply because it is hard to read and I am bored.

Distribution and Control Equipment Terminations ? Most terminals are suitable for use only with copper wire. Where aluminum or copper-clad aluminum wire can or is intended to be used (some crimp terminals may be Listed only for aluminum wire), the product is marked accordingly. Such marking is required to be independent of any marking on terminal connectors, such as on a wiring diagram or other visible location. The marking may be in an abbreviated form, such as "AL-CU."
Except as noted in the following paragraphs or in the general Guide Information for some product categories, the termination provisions are based on the use of 60?C ampacities for wire sizes 14 ? 1 AWG, and 75?C ampacities for wire sizes 1/0 AWG and larger, as specified in Table 310.16 of the NEC.
Some distribution and control equipment is marked to indicate the required temperature rating of each field-installed conductor. If the equipment, normally intended for connection by wire sizes within the range 14 ? 1 AWG, is marked "75C" or "60/75C," it is intended that 75?C insulated wire may be used at full 75?C ampacity. Where the connection is made to a circuit breaker or switch within the equipment, such a circuit breaker or switch will also be marked for the temperature rating of the conductor.
A 75?C conductor temperature marking on a circuit breaker or switch normally intended for wire sizes 14 ? 1 AWG does not in itself indicate that 75?C insulated wire can be used unless 1) the circuit breaker or switch is used by itself, such as in a separate enclosure, or 2) the equipment in which the circuit breaker or switch is installed is also so marked.
A 75 or 90?C temperature marking on a terminal (e.g., AL7, CU7AL, AL7CU or AL9, CU9AL, AL9CU) does not in itself indicate that 75 or 90?C insulated wire can be used unless the equipment in which the terminals are installed is marked for 75 or 90?C.
Higher-temperature-rated conductors than specified may be used if the size is based on the above statements.
Click to expand...
 
cpal said:
sme here but i have very powerfull glasses;)
Click to expand...

Yeah, but I don't! I needed a magnifying glass.:roll:

Dennis Alwon said:
I am redoing Charlie's post simply because it is hard to read and I am bored.
Click to expand...

I am redoing Dennis's post because I am bored.:grin:


Distribution and Control Equipment Terminations ? Most terminals are suitable for use only with copper wire. Where aluminum or copper-clad aluminum wire can or is intended to be used (some crimp terminals may be Listed only for aluminum wire), the product is marked accordingly. Such marking is required to be independent of any marking on terminal connectors, such as on a wiring diagram or other visible location. The marking may be in an abbreviated form, such as "AL-CU."

Except as noted in the following paragraphs or in the general Guide Information for some product categories, the termination provisions are based on the use of 60?C ampacities for wire sizes 14 ? 1 AWG, and 75?C ampacities for wire sizes 1/0 AWG and larger, as specified in Table 310.16 of the NEC.

Some distribution and control equipment is marked to indicate the required temperature rating of each field-installed conductor. If the equipment, normally intended for connection by wire sizes within the range 14 ? 1 AWG, is marked "75C" or "60/75C," it is intended that 75?C insulated wire may be used at full 75?C ampacity. Where the connection is made to a circuit breaker or switch within the equipment, such a circuit breaker or switch will also be marked for the temperature rating of the conductor.

A 75?C conductor temperature marking on a circuit breaker or switch normally intended for wire sizes 14 ? 1 AWG does not in itself indicate that 75?C insulated wire can be used unless 1) the circuit breaker or switch is used by itself, such as in a separate enclosure, or 2) the equipment in which the circuit breaker or switch is installed is also so marked.

A 75 or 90?C temperature marking on a terminal (e.g., AL7, CU7AL, AL7CU or AL9, CU9AL, AL9CU) does not in itself indicate that 75 or 90?C insulated wire can be used unless the equipment in which the terminals are installed is marked for 75 or 90?C.

Higher-temperature-rated conductors than specified may be used if the size is based on the above statements.
 
cwain said:
one is in illustration 240-9 and one is in240-10 both of these use 60c I will be looking for the ones that use 75c and I think I seen a Authers comment that said use 75c for most equipment but I cant find it either but will keep looking. Maybe I just thought I seen it.
Click to expand...

ok, I found the other example in Understanding NEC book on a single phase motor 2hp that used the 75c column. Figure 250-186 Compare that one with figure 240-10
 
infinity said:
I see what you're getting at, not that it matters in this example since a #14 AWG conductor has the same ampacity at both 60 and 75 degrees C.

If you believe that there are errors in the examples you can provide that information directly at:

www.mikeholt.com/bookcorrections.htm
Click to expand...

No Sir , I am in no means trying to point out errors in the book . Mike Holts books are the best! I just wanted to make sure I was doing the ampacities right. Thanks a lot for all the good Info.
 
cwain said:
No Sir , I am in no means trying to point out errors in the book . Mike Holts books are the best! I just wanted to make sure I was doing the ampacities right. Thanks a lot for all the good Info.
Click to expand...


It seems, as you've pointed out, that there are some inconsistencies in a few of Mike's examples. Even though I own that particular book I never noticed them. I'm not sure why they're present. They could be an oversight or are there for deliberate reason.
 
infinity said:
It seems, as you've pointed out, that there are some inconsistencies in a few of Mike's examples. Even though I own that particular book I never noticed them. I'm not sure why they're present. They could be an oversight or are there for deliberate reason.
Click to expand...

It will sure make you dig a little deeper. which is a good thing in the long run. Thanks alot.
 
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