# 60C rated terminations - NEC110.14(C) - Some examples



## Carultch (May 14, 2013)

In practice, I've observed that it is the industry norm that terminals/equipment are most likely rated for 75C. Certainly applies to 101 amps and greater, per this rule.

I'm aware that #10 wire and smaller has special limits, such as #10 can't be put on anything larger than a 30A breaker.

For #8 wire and larger, within the 100A and less applications, how common is it in practice, that a termination is only rated for 60C? What are some examples of termination types where I should design around this?

NEC110.14(C) says that it is the default for 100A and less equipment to be rated 60C, however I have heard that this is mostly academic at this point, rather than practical, since terminations listed and marked 75C are more common.


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## Black Dog (Oct 16, 2011)

Carultch said:


> In practice, I've observed that it is the industry norm that terminals/equipment are most likely rated for 75C. Certainly applies to 101 amps and greater, per this rule.
> 
> I'm aware that #10 wire and smaller has special limits, such as #10 can't be put on anything larger than a 30A breaker.
> 
> For #8 wire and larger, within the 100A and less applications, how common is it in practice, that a termination is only rated for 60C? What are some examples of termination types where I should design around this?


Every time you use Romex....


334.80 Ampacity. The ampacity of Types NM, NMC, and NMS cable shall be determined in accordance with 310.15. *The allowable ampacity shall not exceed that of a 60°C (140°F) *rated conductor. The 90°C (194°F) rating shall be permitted to be used for ampacity adjustment and correction calculations, provided the final derated ampacity does not exceed that of a 60°C (140°F) rated conductor. The ampacity of Types NM, NMC, and NMS cable installed in cable tray shall be determined in accordance with 392.80(A).
Where more than two NM cables containing two or more current-carrying conductors are installed, without maintaining spacing between the cables, through the same opening in wood framing that is to be sealed with thermal insulation, caulk, or sealing foam, the allowable ampacity of each conductor shall be adjusted in accordance with Table 310.15(B)(3)(a) and the provisions of 310.15(A)(2), Exception, shall not apply.
Where more than two NM cables containing two or more current-carrying conductors are installed in contact with thermal insulation without maintaining spacing between cables, the allowable ampacity of each conductor shall be adjusted in accordance with Table 310.15(B)(3)(a).


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## hardworkingstiff (Jan 22, 2007)

Carultch said:


> NEC110.14(C) says that it is the default for 100A and less equipment to be rated 60C, however I have heard that this is mostly academic at this point, rather than practical, since terminations listed and marked 75C are more common.


I agree about it being academic (terminals are almost all rated 75C or higher).


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## Dennis Alwon (May 9, 2009)

Carultch said:


> In practice, I've observed that it is the industry norm that terminals/equipment are most likely rated for 75C. Certainly applies to 101 amps and greater, per this rule.


 This is true and it would also apply to under 100 amps as long as the wire and terminals are 75C



> I'm aware that #10 wire and smaller has special limits, such as #10 can't be put on anything larger than a 30A breaker.


 Not necessarily true



> For #8 wire and larger, within the 100A and less applications, how common is it in practice, that a termination is only rated for 60C?


 Older equipment iot may have been common but now they are all 75C



> What are some examples of termination types where I should design around this?


 Not sure what you want here-- I would assume 75C everywhere with new equipment



> NEC110.14(C) says that it is the default for 100A and less equipment to be rated 60C, however I have heard that this is mostly academic at this point, rather than practical, since terminations listed and marked 75C are more common.


 This is true. It would be rated 60C only if there is no marking on the terminals or panelboard or if it is marked 60C . If it is marked 75C then you can use 75C assuming everything else equal


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## Carultch (May 14, 2013)

Thank you very much everyone for your replies. Very helpful.

I never use Romex anyway, in most of the scope of work I do. I try to spec 90C rated wire. THWN-2 is very common.

My question was about termination ratings only. The wire obviously has its own requirements.

And since I'm not always in control of exact manufacturers for terminal and equipment selection, I'm hoping to get a general idea of what kinds of equipment would require me to follow the 60C rating.


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## chicken steve (Mar 22, 2011)

While 110.14C applies, the confusion i often have is how the many forms of derating _overlay_, or _relate_ to each other

Consider....

we have 110.14C, _(terminations)_

we have T310.15b16 _(former 310.16)_ , 

we have T310.15B7 _(resi service & feeders)_, 

we have T310.15B2b _(ambient temp) _, 

we have T310.15B3a _(pipe or raceway)_

~CS~


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## 360max (Jun 10, 2011)

Carultch said:


> In practice, I've observed that it is the industry norm that terminals/equipment are most likely rated for 75C. Certainly applies to 101 amps and greater, per this rule.
> 
> I'm aware that #10 wire and smaller has special limits, such as* #10 can't be put on anything larger than a 30A breaker.*
> 
> ...


not true when dealing with motors, a #10 awg could be placed on a 40, 50, 60, 70, 80 amp breaker.


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## chicken steve (Mar 22, 2011)

> (4) For* motors *marked with design letters B, C, or D, con-
> ductors having an insulation rating of 75°C (l67°P) or
> higher shall be permitted to be used, provided the am-
> pacity of such conductors does not exceed the 75°C
> (l67°P) ampacity.


So would this be conflicting , with a #10 on a 60A ocdp ?, or do the OL's prevent the conductor(s) from achieving 167F? 

~CS~


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## Carultch (May 14, 2013)

360max said:


> not true when dealing with motors, a #10 awg could be placed on a 40, 50, 60, 70, 80 amp breaker.


I don't work with the motor section very often, so I'm not familiar with all the exotic rules that apply there. I do know that motors change everything, because of the fact that current spikes on the inrush, and then settles once the motor is in motion.

What I was speaking of in that sentence, is the footnote at the bottom of 310.15(B)(16), that references 240.4(D). The "small conductor rule". I included that sentence, to direct our attention away from the small conductors and focus on sizes #8 through #2.


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## Carultch (May 14, 2013)

chicken steve said:


> While 110.14C applies, the confusion i often have is how the many forms of derating _overlay_, or _relate_ to each other
> 
> Consider....
> 
> ...


With 90C rated wire, T310.15(B)(2)(b) and T310.15(B)(3)(A) will both apply to the 90C.

With 110.14(C), it doesn't matter what wire you use. The terminations are what matters. Even more counterintuitive, is when terminals on manufactured equipment are marked AL9CU, and that still isn't good enough for using the 90C column in regards to 110.14(C).


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