Conduit size

[roger]

I am more confused now than before.:huh:

Roger

 

[kwired]

I am sorry, I know a few complain about me at times on this site, others seem to like what I have to say, everyone is different and that is part of life. I am not trying to badger anyone, but please tell me how 110.14(C) has anything to do with ampacity adjustment? Ampacity adjustment is for conductors not terminations, 110.14 is not even about conductors, it is about terminations

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.

Nothing in there says anything about how or where to start with ampacity adjustments - it basically says the conductor can not be less then the smallest conductor permitted on the terminal per the terminals temperature rating, but does give permission to adjust the conductor starting at the conductor rating if it is higher then the termination rating.

 

[roger]

I am sorry, I know a few complain about me at times on this site, others seem to like what I have to say, everyone is different and that is part of life. I am not trying to badger anyone, but please tell me how 110.14(C) has anything to do with ampacity adjustment? Ampacity adjustment is for conductors not terminations, 110.14 is not even about conductors, it is about terminations



Nothing in there says anything about how or where to start with ampacity adjustments - it basically says the conductor can not be less then the smallest conductor permitted on the terminal per the terminals temperature rating, but does give permission to adjust the conductor starting at the conductor rating if it is higher then the termination rating.

You need to read it again, especially this part

Conductors with temperature ratings higher than specified for terminations shall be permitted to be used for ampacity adjustment, correction, or both.

After that read 110.14(C)(1) and notice how many times is specifically talking about "conductors', you can't have a termination without a conductor and if you do you don't need to worry about the insulation rating anyways.

You stated that the permission to start a conductor ampacity adjustment with a higher insulation rating than the termination "is not exactly stated in one simple sentence in one code section", and I showed you where it is, go with it and don't loose any more sleep over it.

Roger

 

[kwired]

You need to read it again, especially this part After that read 110.14(C)(1) and notice how many times is specifically talking about "conductors', you can't have a termination without a conductor and if you do you don't need to worry about the insulation rating anyways.

You stated that the permission to start a conductor ampacity adjustment with a higher insulation rating than the termination "is not exactly stated in one simple sentence in one code section", and I showed you where it is, go with it and don't loose any more sleep over it.

Roger

Okie dokie

 

[JGRC]

Does this not specifically mean you can use the 90C:

Conductors with temperature ratings higher than specified for terminations shall be permitted to be used for ampacity adjustment, correction, or both.

Every class I have ever taken where temp correction was involved instructed this.

 

[JGRC]

Example Right Out of a Book

Example Right Out of a Book

Example from exam prep book

 

[JGRC]

Are we on the same page? I expect someone like you already knows this but maybe we are not talking about the same thing here causing some confusion.

It is not exactly stated in one simple sentence in one code section.

310.15 applies to the conductors - we make adjustments from 90 degree values if we have 90 degree insulation.

However after making adjustments we still must have a conductor no smaller then what is called for in the 60 or 75 degree columns of ampacity table for the sake of termination temperatures. That gets us back to what was mentioned about 110.14 Two different ampacities are required for same conductor in different portions of the conductor - the higher ampacity is what must be used, but don't know of any possible adjustments to termination ampacity, just to conductor ampacity only as it applies to it's insulation.

You can have a situation where ampacity adjustment says you can have a 6 AWG conductor for the temp rating of the insulation, but same application may need 4 AWG for the termination temperature - so in that case you still must use the 4 AWG.

I agree with kwired explanation. The "termination" degree rating is strictly the ratings of the equipment and its terminations (mechanical lugs and such) under UL testing. The conductor size acts as a heat sink which is why there is a degree listing in the first place.


I think the confusion is in the interpretation of the word termination.

Since there is no 90 C listed equipment there wouldn't be a need for this table if not for the use of 90 C wire adjustment and correction factors.


Mike Holts Video...Fast Forward to 8:50
https://www.youtube.com/watch?v=OLIHEiiY_Rs

 

[roger]

I agree with kwired explanation. The "termination" degree rating is strictly the ratings of the equipment and its terminations (mechanical lugs and such) under UL testing. The conductor size acts as a heat sink which is why there is a degree listing in the first place.

Why do you think anybody is contesting what he said?

I think the confusion is in the interpretation of the word termination.

I don't see anybody confused about the word termination.

Since there is no 90 C listed equipment there wouldn't be a need for this table if not for the use of 90 C wire adjustment and correction factors.

There is 90 deg terminations, just not very common.

The only confusion was to what 110.14(C) says in the last sentence so tell us what you think it says and means.

Roger

 

[JGRC]

You need to read it again, especially this part After that read 110.14(C)(1) and notice how many times is specifically talking about "conductors', you can't have a termination without a conductor and if you do you don't need to worry about the insulation rating anyways.
Roger

Switch Gear comes with terminations (LUGS) you just need to land the conductors. Code makes a distinction.110.14(C) 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. Code makes a distinction of connected termination which mean there can be a non connected termination.

As uncommon as you mention 90 C terminations can be.......... I didn't even imply they were uncommon if fact they are fairly common, my point is there is no 90 C EQUIPMENT . Don't matter what the Terminations (LUGS) are rated for above 75 C if the gear is 75 C .Which is why anything over 100 amps is treated as 75 C.

110.14(C)(1)(b)(2) Conductor with higher temperature ratings, provided the ampacity of such conductor does not exceed the 75 C ampacity of the conductor size used
This would include correction factors at 90 C

 

[JGRC]

Last sentence of 110.14(C) I interpret as the clearest distinction that you can apply correction factors at 90 C since on the contrary there wouldn't be a need to write that last sentence and your only option would be to use 75 C. Code would have done away with 90 C ratings since no equipment is 90 C.

In my opinion the 90 C is mainly in the code to be able to use the correction factors on conductors like the example I posted on #26

 

[roger]

Last sentence of 110.14(C) I interpret as the clearest distinction that you can apply correction factors at 90 C

Exactly!!!

Roger

 

[JGRC]

Are we on the same page? I expect someone like you already knows this but maybe we are not talking about the same thing here causing some confusion.

It is not exactly stated in one simple sentence in one code section.

310.15 applies to the conductors - we make adjustments from 90 degree values if we have 90 degree insulation.

However after making adjustments we still must have a conductor no smaller then what is called for in the 60 or 75 degree columns of ampacity table for the sake of termination temperatures. That gets us back to what was mentioned about 110.14 Two different ampacities are required for same conductor in different portions of the conductor - the higher ampacity is what must be used, but don't know of any possible adjustments to termination ampacity, just to conductor ampacity only as it applies to it's insulation.

You can have a situation where ampacity adjustment says you can have a 6 AWG conductor for the temp rating of the insulation, but same application may need 4 AWG for the termination temperature - so in that case you still must use the 4 AWG.

I feel his pain lol
Seem like we are on the same page.
Post #16 was interpreted wrong by a few of us lol
kwired meant you could not use correction factors @90 C for wire only rated at 75C such as USE that does not have a USE-2 stamp on in making it also 90 C ( if there is such a thing). Taken the wrong way apparently. Then the whole termination thing

 

[Carultch]

As uncommon as you mention 90 C terminations can be.......... I didn't even imply they were uncommon if fact they are fairly common, my point is there is no 90 C EQUIPMENT . Don't matter what the Terminations (LUGS) are rated for above 75 C if the gear is 75 C .Which is why anything over 100 amps is treated as 75 C.

Is it really an absolute thing that no equipment is rated to use the 90C column of the NEC for 90C connections?

This datasheet from Bentek says "90º C output terminals with M8 stud for compression lugs".
http://www.bentek.com/wp-content/uploads/991-003869-000-E-Bentek-Grounded-IntDisc-Combiners-DS.pdf

I know that in a general sense, an AL9CU lug on a piece of equipment does not necessarily allow you to take credit for the 90C column of the NEC for 110.14(C). But is it still possible (albeit rare) that a listed piece of equipment, can be manufactured, listed, and labeled for you to use the 90C column of 310.15(B)(16)?

If it weren't the case that 90C equipment as a listed assembly could exist, I don't know why Bentek would even have a reason to write that on their datasheet.

Another example would be solar modules, which come with a pair of 3 ft of factory 90C rated wire, and a factory 90C rated connector. I can't think of a situation where you would be able to connect 90C sized string wire to it, but in principle, would this be such a case where you could do this?

 

[roger]

kwired meant you could not use correction factors @90 C for wire only rated at 75C such as USE that does not have a USE-2 stamp on in making it also 90 C

If you say so. :roll:

Roger

 

[DrSparks]

I stand corrected. For the purposes of # CCC adjustment, we use the 90 deg column. Sorry for the confusion I created. :? Hey let's start a new argument. When do you count the neutral as a CCC in a network? :lol:

 

[Carultch]

I stand corrected. For the purposes of # CCC adjustment, we use the 90 deg column. Sorry for the confusion I created. :? Hey let's start a new argument. When do you count the neutral as a CCC in a network? :lol:

To summarize it:
Neutral counts as a CCC, if it is a mandatory part of the return path for the current. Or if nonlinear/harmonics currents account for a major portion of the loads.

Examples where neutral is a "mandatory part of the path for the return current":
1. Phase-to-neutral single phase circuits
2. Two phases + a neutral, from a three-phase main circuit, used with phase-to-neutral loads on each. 100A on phase A + 100A on phase B requires 100A to return on the neutral when phase C is not present.

Examples where it doesn't count.
1. Three phase circuits from a WYE system with linear loads, no matter what the imbalance (if any)
2. Split-phase circuits from a single phase system with linear loads, no matter what the imbalance (if any)
3. Where it is only connected for instrumentation purposes, and doesn't ever carry significant current.

The condition of nonlinear/harmonic loads is very obscure and difficult to objectively know. The follow up question is, given an oscilloscope graph of the voltage and current for that particular load, how can one know for sure if it neutral would have to count as a CCC?

 

[DrSparks]

To summarize it:
Neutral counts as a CCC, if it is a mandatory part of the return path for the current. Or if nonlinear/harmonics currents account for a major portion of the loads.

Examples where neutral is a "mandatory part of the path for the return current":
1. Phase-to-neutral single phase circuits
2. Two phases + a neutral, from a three-phase main circuit, used with phase-to-neutral loads on each. 100A on phase A + 100A on phase B requires 100A to return on the neutral when phase C is not present.

Examples where it doesn't count.
1. Three phase circuits from a WYE system with linear loads, no matter what the imbalance (if any)
2. Split-phase circuits from a single phase system with linear loads, no matter what the imbalance (if any)
3. Where it is only connected for instrumentation purposes, and doesn't ever carry significant current.

The condition of nonlinear/harmonic loads is very obscure and difficult to objectively know. The follow up question is, given an oscilloscope graph of the voltage and current for that particular load, how can one know for sure if it neutral would have to count as a CCC?

Exactly, which is why it's so heavily debated. Definitely would consider electronic ballasts a non-linear load. I've gotten in debates about this many times. For convenience receps, we might as well consider it non-linear because anything could be plugged in. Just about all devices now-a-days produce non-sinusoidal signals.

 

[kwired]

Exactly, which is why it's so heavily debated. Definitely would consider electronic ballasts a non-linear load. I've gotten in debates about this many times. For convenience receps, we might as well consider it non-linear because anything could be plugged in. Just about all devices now-a-days produce non-sinusoidal signals.

310.15(B)(5)(c):

On a 4-wire, 3-phase wye circuit where the major portion of the load consists of nonlinear loads, harmonic currents are present in the neutral conductor; the neutral conductor shall therefore be considered a current-carrying conductor.

This is only a problem when the non linear load is a major portion of the neutral load in a wye system. An occasional light load doesn't add a significant amount of harmonic current.

Even a facility with mostly electronic ballast lighting doesn't necessarily have a majority of all the neutral load being harmonic producing load. There may be more other linear load then there is lighting load. VFD's produce harmonics, but your typical three phase drive has no neutral conductor either, the issue here is about the neutral conductor in wye systems.