Well that's the usual discourse for something that should be explicit but not.And basically I believe that most can convince the EI that they are saying roughly the same thing, that you can use a higher temperature rated insulation (much like we do with NM-B) and still meet the 60 degree. To be honest with you I find this a little "over anal-ising" something that is just not really there in THIS example. Might apply in other examples but in this example I would not tell the contractor to upsize anything....
But as we tend to say here....we can agree to disagree...we will let the games begin when the contractor meets the inspector and let them hash it out. Much like the handbook, we are all full of interpretations and i'm set on mine...
Termination Temperature Rating & Upsizing Ground
- Thread starter PowerEE
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- Connecticut
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- Engineer
I don't see where 110.14(C)(1)(a)(3) says you must use the the 75 deg column for 75 and 90 conductors.
110.14(C)(1)(a) says termination provisions for circuits rated 100A or less, or marked for 14AWG through 1AWG conductors, shall be used only for ONE of the following:
110.14(C)(1)(a)(1) permits you to use 60deg conductors.
110.14(C)(1)(a)(2) permits you to use a conductor rated higher than 60deg, provided the ampacity is based on the 60 deg column.
110.14(C)(1)(a)(3) permits you to use a conductor rated higher than 60deg if the equipment is listed and identified for use with such conductors.
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RichB
Senior Member
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- Tacoma, Wa
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- Electrician/Electrical Inspector
Kinda like a pondcutor but comes first alphabetically:ashamed:
It is not the 'ONE' part of 110.14(C)(1)(a) that sets the determination... it's the 'SHALL'. The only use of 'permitted' is in 110.14(C)(1)(a)(4).
It seems to me 110.14(C)(1)(a) says, "If the condition of use is as noted, with the exception of 110.14(C)(1)(a)(4), you MUST use it."
- Location
- Connecticut
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- Engineer
I don't see any language in 110.14 (C)(1)(a) about "if the condition of use is as noted"...
If the condition of use is a termination rated 100A or less and the termination is not rated higher than 60 degree would you be required to comply with (a)(1) and (a)(2) simultaneously? How would one accomplish that?
It's an 'if...then..." requirement in the respect that "only one of the following" "provisions... shall be used".
1) Conductors are not rated 60 degrees C... so cannot be used.
2) Conductors have a higher temperature rating... but this seems to be based on equipment not listed and identified for use with such conductors.
3) Conductors have a higher temperature rating... and equipment is listed and identified for use with such conductors. This is the only one of all four that matches design parameters.
4) Not considered for this exercise.
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- Connecticut
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- Engineer
Again, the "if-then" component doesn't exist in the language of 110.14 (C)(1)(a). You are injecting that yourself. If I have a 60A, 75 deg rated termination and use a 75 deg conductor limited to the 60 deg ampacity, then I am using the termination with ONE of the conductors listed in 110.14 (C)(1)(a). That meets the code requirements.
If I had a 60 deg term run to a 90 deg term then to a 90 deg term and finally to a 60 deg term, and I connected a 60 deg conductor at both ends to the 60 degree terms, could I continue to run the 60 degree conductor between the 90 degree terms, or would I have to run a 90 degree conductor for the middle portion?
Yet in this case, with a 60/75 termination, you are not limited to the 60 deg ampacity. 250.122(B) refers to the minimum size wire (for the conditions of use). Applying 60 deg termination requirements to a termination which is capable of a smaller wire with 75 deg wire and applying 75 deg termination requirements would be the minimum size. Using the wire sized per the 60 deg column is IMO upsized.
Have no idea how this even applies to the issue. The only matter in question is a termination with a 60/75 listed and identified rating.
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PowerEE
Member
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- Fort Worth, Texas, united States
Further Clarification?
Further Clarification?
Thank you for all your responses. I wish I could reply to just one poster, but is difficult with all the mixed responses. Hopefully, if I present something a little more specific, this will help reveal the intent of my questions.
First, it is my understanding, or interpretation, that code 110.15(C)(1) only applies to unmarked equipment. If the equipment is marked with the termination ratings, then we know exactly how to size our wires.
For new commercial construction, is there any piece of equipment that is not marked, and not marked for at least 75* C? If there is no such equipment, why would I apply 110.15(C)(1) and size for 60* C, especially if the standard (or specifications) is to use THWN 75* C or THHN 90* C wire? I would be grossly oversizing my wire for the 90* C case.
This is what led to my question regarding upsizing the ground. This oversized wire can greatly increase the available ground fault current at the equipment, which is the very reason for 250.122(B).
Further Clarification?
Thank you for all your responses. I wish I could reply to just one poster, but is difficult with all the mixed responses. Hopefully, if I present something a little more specific, this will help reveal the intent of my questions.
First, it is my understanding, or interpretation, that code 110.15(C)(1) only applies to unmarked equipment. If the equipment is marked with the termination ratings, then we know exactly how to size our wires.
For new commercial construction, is there any piece of equipment that is not marked, and not marked for at least 75* C? If there is no such equipment, why would I apply 110.15(C)(1) and size for 60* C, especially if the standard (or specifications) is to use THWN 75* C or THHN 90* C wire? I would be grossly oversizing my wire for the 90* C case.
This is what led to my question regarding upsizing the ground. This oversized wire can greatly increase the available ground fault current at the equipment, which is the very reason for 250.122(B).
I believe others have stated typical 15 and 20A duplex receptacles and perhaps wall switches are not rated 75?C.
PowerEE
Member
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- Fort Worth, Texas, united States
Ah I must have missed that. I guess I am more concerned with equipment requiring 50A to 100A OCP. This is the range where wire sizes begin to differentiate from 60* C to 90* C. A commercial grade 20A receptacle is going to be #12 either way.
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