Termination limitations.

[wwhitney]

Why no adjustment or correction?

No adjustment because in the vicinity of the termination, the conductors aren't in a common cable or raceway.

No correction because the equipment manufacturer has taken care of that, the specified temperature column of Table 310.16 is your conversion from amps to wire size for that termination.

Of course, through the run of the conduit you have to do adjustment and correction. That's completely separate; nothing we've said about termination is applicable to those checks.

Cheers, Wayne

 

[Pinnie]

No correction because the equipment manufacturer has taken care of that, the specified temperature column of Table 310.16 is your conversion from amps to wire size for that termination

would you still have to correct for the ambient temperature the equipment/terminal is in from that specified ampacity?

Of course, through the run of the conduit you have to do adjustment and correction. That's completely separate; nothing we've said about termination is applicable to those checks.

gotcha thank you for saying that i was going to ask.

 

[wwhitney]

would you still have to correct for the ambient temperature the equipment/terminal is in from that specified ampacity?

Again, no. The equipment will specify what ambient temperatures it may be installed in. The manufacturer's testing for the listing standard will ensure that if the equipment is installed in the maximum allowable ambient temperature, and the wire is sized using the Table 310.16 column for the termination temperature specified (spec (a) in post #39), no adjustment or correction, then the termination temperature will not exceed the minimum specified conductor insulation temperature (spec (b) in post #39).

So the equipment manufacturer has done it all for the field installer. The manufacturer tells the field installer (a) how to size the wire to land on the terminal (look at the specified column in Table 310.16, just a straight lookup, no further calculations) and (b) the minimum insulation temperature that wire must have (usually the temperature from (a), but as discussed, not always).

Now if you are misusing a piece of equipment outside the allowable temperature range the manufacturer specifies, which implies you don't care about code compliance, and you want to maximize its chance of not overheating, then I'd say you'd be wise to further upsize the wire in accordance with how much you are exceeding the top end of the allowable temperature range. Because physics.

Cheers, Wayne

 

[Pinnie]

Again, no. The equipment will specify what ambient temperatures it may be installed in. The manufacturer's testing for the listing standard will ensure that if the equipment is installed in the maximum allowable ambient temperature, and the wire is sized using the Table 310.16 column for the termination temperature specified (spec (a) in post #39), no adjustment or correction, then the termination temperature will not exceed the minimum specified conductor insulation temperature (spec (b) in post #39).

yes of course. they would take care of that.

Now if you are misusing a piece of equipment outside the allowable temperature range the manufacturer specifies, which implies you don't care about code compliance, and you want to maximize its chance of not overheating, then I'd say you'd be wise to further upsize the wire in accordance with how much you are exceeding the top end of the allowable temperature range. Because physics.

wise words

 

[mtnelect]

For HVAC (Heating Ventilation Air Conditioning) check the manufacturer instructions foot notes first, before wiring is always a good idea.

 

[Pinnie]

For HVAC (Heating Ventilation Air Conditioning) check the manufacturer instructions foot notes before wiring is always a good idea.

Yes of course, thank you sir. I have yet to size a conductor for hvac but i know its a an exception in 240.4. I will have to study that more before I'd feel safe doing it lol.

 

[jim dungar]

would you still have to correct for the ambient temperature the equipment/terminal is in from that specified ampacity?

All of those adjustments affect the ampacity of the conductors. None of them affect the temperature rating of the conductor insulation.

 

[Pinnie]

I’m trying understand 110.14 (C).
“C) Temperature Limitations. The temperature rating associated with the ampacity of a conductor shall be selected and coordinated so as not to exceed the lowest temperature rating of any connected termination, conductor, or device. Conductors with temperature ratings higher than specified for terminations shall be permitted to be used for ampacity adjustment, correction, or both.”

shouldn’t it say the ampacity associated with the temperature rating of the conductor not the other way around?

 

[jim dungar]

shouldn’t it say the ampacity associated with the temperature rating of the conductor not the other way around?

No.
It is possible that a termination requires 90°C insulation but with its ampacity based on the table 75°C column. You do not use the ampacity that is directly associated with the conductor insulation.

 

[Pinnie]

No.
It is possible that a termination requires 90°C insulation but with its ampacity based on the table 75°C column. You do not use the ampacity that is directly associated with the conductor insulation.

Yes but what it’s literally saying is the temperature rating of a conductor cannot exceed the temperature rating of anything in the circuit? Then in the next sentence appears to give an exception to that saying you can use the higher temperature rated conductor, but only when derating. (and it is limited to ampacity of the corresponding temperature rating to termination temperature rating)

 

[jim dungar]

Yes but what it’s literally saying is the temperature rating of a conductor cannot exceed the temperature rating of anything in the circuit? Then in the next sentence appears to give an exception to that saying you can use the higher temperature rated conductor, but only when derating. (and it is limited to ampacity of the corresponding temperature rating to termination temperature rating)

Dont read too much into it.
The final temperature rating used for selecting ampacity cannot exceed the temperature rating of the termination.

Higher insulation temperature ratings may only be used for adjustments and corrections.

 

[Pinnie]

Dont read too much into it.
The temperature rating used for selecting ampacity cannot exceed the temperature rating of the termination.

Higher insulation temperature ratings may be used for adjustments and corrections.

I think it could be written better. Not saying by me but it’s hard to read as a novice.

 

[jim dungar]

I think it could be written better. Not saying by me but it’s hard to read as a novice.

Sorry I edited after you replied.

I think the NEC language is not ambiguous although I think it is a little bit of a run on sentence

 

[Pinnie]

Sorry I edited after you replied.

I think the NEC language is not ambiguous although I think it is a little bit of a run on sentence

I understand the way you said it but the way it’s written makes it sound like you can’t use 90C conductors unless the termination rating is 90C.