110.14(C) - Temperature Limitations at Connections

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rbalex

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1.) NEC Section/Paragraph: 110.14(C)(1)
2.) Proposal Recommends: Replace existing text as follows
3.) Proposal:
110.14 (C) Ampacity and Temperature Limitations of Electrical Connections. The ampacity of a conductor shall be selected and coordinated so as not to exceed the ampacity or temperature rating of any connecting device or equipment terminal it is connected to [Edit Add:] or the temperature rating of any material or equipment it is in contact with.

(1) Provisions for 0-600V Connecting Devices or Equipment Terminals. Temperature limitations of conductors, required by 0-600V rated connecting devices or equipment terminals, shall be based on 110.14(C) (1) (a), (b) or (c). Unless marked otherwise, the conductor ampacity at a connecting device or equipment terminal shall be based on Table 310.16 without further adjustment except as required by the appropriate ambient correction factor of the conductor.

(a) Connecting devices or equipment terminals rated 100 amperes or less, or marked for conductors 14 AWG through 1 AWG, shall be used only for one of the following:

(1) Conductors with temperature ratings of 60?C (140?F)
(2) Conductors with higher temperature ratings, provided the ampacity of such conductors at the connecting device or equipment terminal is limited to the ampacity of a 60?C (140?F) temperature rated conductor of the same size
(3) Conductors with higher temperature ratings if the connecting device or the equipment terminal and host equipment is identified for use with such conductors


(b) Terminations rated over 100 amperes, or marked for conductors larger than 1 AWG, shall be used only for one of the following:

(1) Conductors with temperature ratings not more than 75?C (167?F)
(2) Conductors with higher temperature ratings, provided the ampacity of such conductors at the connecting device or equipment terminal is limited to the ampacity of a 75?C (167?F) temperature rated conductor of the same size
(3) Conductors with higher temperature ratings if the connecting device or the equipment terminal and host equipment is identified for use with such conductors

(c) For motors marked with NEMA design letters B, C, or D, field terminated conductors shall have a temperature rating not more than 75?C (167?F) or conductors with higher temperature ratings shall be permitted to be used provided the ampacity at the termination of such conductors is limited to the ampacity of a 75?C (167?F) temperature rated conductor of the same size.
4.) Substantiation:
This Subsection is still widely misunderstood and needs clarification that these are ampacity and temperature limitations solely at the connections.

In the context of the Primary Section (110.14) the purpose of this Subsection is to define the appropriate temperature limitations of conductors at connections. The temperature limitations of the conductors in other conditions of use are appropriately defined in Section 310.10 and other parts of Article 310. It is important to note no additional adjustments are required by a connection itself unless marked otherwise, but ambient conditions are to be considered.

A coordinating Proposal is being made to Section 310.15(A)(2) [ Selection of Ampacity ]to specifically recognize 110.14(C) and that the Exception 310.15(A)(2)does not apply to it.

The revised text also notifies the user that both the host equipment and it terminals must be identified for a higher temperature ratings.

Termination devices in 110.14(C)(2) are both amp and temperature rated so ampacity restrictions are also recognized in the 110.14(C) general statement.

Non-listed NEMA rated motors are identified as the basis for 110.14(C)(1)(c)
Note to the Forum: Be Gentle :D

[ May 05, 2005, 10:15 AM: Message edited by: rbalex ]
 
Re: 110.14(C) - Temperature Limitations at Connections

Holy jeez, this is thick. :eek:

Originally posted by rbalex:
Terminations rated over 100 amperes, or marked for conductors larger than 1 AWG, shall be used only for one of the following:

(1) Conductors with temperature ratings not more than 75?C (167?F)
I think the existing text is clearer than this. This appears to forbid 90? conductors from pulling over 100 amps. ;) )
 
Re: 110.14(C) - Temperature Limitations at Connections

Unfortunately it has to be thick; conductor ampacities versus connection temperature ratings is a very misunderstood subject.

If you haven't already looked at it, check this thread. Have you always been aware the application of this section is limited to ampacity and/or temperature ratings of connections?

Re-read the Proposal carefully; what the proposed new 110.14(C)(1)(b) (1) permits is 60C rated conductors to also be used at their own rating for over 100A circuits; i.e., it doesn't limit over 100A circuits to 75C rated conductors.

Both the proposed new 110.14(C)(1)(b) (2) and (3) permits use of 90C conductors with appropriate limitations. As do 110.14(C)(1)(a) (2) and (3) for under 100A circuits.

You also want to carefully study the definition of ampacity, especially with reference to "conditions of use." Indeed it is always a 75C rated conductor, because ambient temperature affects its ampacity - not its temperature rating. Also study the "coordinating" proposal.

BTW I have also used the NEC defined term identified carefully.

[ April 07, 2005, 10:38 PM: Message edited by: rbalex ]
 
Re: 110.14(C) - Temperature Limitations at Connections

Okay, I've skimmed the source thread, and am up to speed on what I too have always done wrong. This originally seemed like a simple concept made way too hard, and now seems like a medium concept made way too hard.

Unfortunately it has to be thick; conductor ampacities versus connection temperature ratings is a very misunderstood subject.
Bob, doesn't this seem self-defeating? :D
 
Re: 110.14(C) - Temperature Limitations at Connections

Originally posted by georgestolz:

Okay, I've skimmed the source thread, and am up to speed on what I too have always done wrong. This originally seemed like a simple concept made way too hard, and now seems like a medium concept made way too hard.
...
George,

Personally, I think its a very hard concept because it is so routinely misunderstood. ;)

Seriously, I'm open to rewording the entire Proposal again if necessary to make it a medium concept made medium - or simple if possible. Getting ideas to do that is a major purpose of this Forum.

I do believe I can explain it "technically" better if I could start from the text I proposed rather than what's there now. What would make it clearer to you?
 
Re: 110.14(C) - Temperature Limitations at Connections

Originally posted by rbalex:
...
Seriously, I'm open to rewording the entire Proposal again if necessary to make it a medium concept made medium - or simple if possible. Getting ideas to do that is a major purpose of this Forum.
...
I've rethought this statement. From the perspective of "Code text," I really don't care whether or not the "why" is undersood; I only care if the "how to" is clear.

So, with that in mind, and knowing "...what I too have always done wrong," would you now know "how to" more clearly? If not - then how would you suggest making it clearer?
 
Re: 110.14(C) - Temperature Limitations at Connections

Revised Substantiation:

This Subsection is still widely misunderstood and needs clarification that these are conductor ampacity and temperature limitations solely at the connections.

Because Ampacity is an NEC defined term, in the context of the primary Section (110.14), the purpose of this Subsection is to define the appropriate ampacity limitations of conductors "in the conditions of use" at connections. The temperature limitations of a conductor in other "conditions of use" with regard to its own temperature rating are appropriately defined in Section 310.10 and other parts of Article 310. It is important to note no additional adjustments are required by a connection itself unless marked otherwise, but ambient conditions are still to be considered.

A coordinating Proposal is being made to Section 310.15(A)(2) [ Selection of Ampacity ] to specifically recognize 110.14(C) and that the Exception in 310.15(A)(2) does not apply to it.

The revised text also notifies the user that both the host equipment as well as its terminals must be identified for use with higher conductor temperature ratings.

Termination devices in 110.14(C)(2) are both ampacity and temperature rated so ampacity restrictions are also recognized in the 110.14(C) general statement.

Non-listed NEMA rated motors are identified as the basis for 110.14(C)(1)(c)
Its the Substantiation that needs to say "why." :D

[ April 08, 2005, 10:47 AM: Message edited by: rbalex ]
 
Re: 110.14(C) - Temperature Limitations at Connections

Originally posted by rbalex:
If not - then how would you suggest making it clearer?
I have to master it first! :D


I'll be back with ideas when I have them, I promise. :D
 
Re: 110.14(C) - Temperature Limitations at Connections

I just thought I'd stop by and say that if I wasn't grinding my own axe in Article 210 I might look into this.

Hi Bob.

That, and, wow, this is a huge piece of document.

And George, if you don't slow down you'll pass all of us up.
 
Re: 110.14(C) - Temperature Limitations at Connections

You also forgot a few things:

1. Derating for 4 or more conductors.

2. In some instances, a circuit can run at 2 different temperatures. If wires from a panelboard go through a wireway with lots of space between the wires and the panelboard itself has the wires tied to telephone distribution posts with spacing maintainted, there is no reason why the conductors inside the panel can be operated at 60 or 75 Celsius and 90 Celsius in the smaller conduits. In fact, I did this with receptacles that were installed in rigid conduit in a "trench drain" in the floor of a factory. Standard locking receptacles rated 20 or 30 amperes have 90 Celsius capable terminals so that there are no problems with wiring that is embedded in thermal insulation. This allowed me to have 9 rather than 6 current carrying conductors in a conduit in the trench.

3. In some instances such as SquareD 15 to 30 amp circuit breakers the terminals are rated for either 60 or 75 Celsius operation. 60 Celsius only terminals only exist in cheap junk.

4. In the case of 100% rated circuit breakers and class L fusible switches, the wires need to be sized for 75 degrees Celsius operation but must have insulation rated for 90 degrees Celsius.
 
Re: 110.14(C) - Temperature Limitations at Connections

Originally posted by mc5w:
Standard locking receptacles rated 20 or 30 amperes have 90 Celsius capable terminals
I do not believe there are any 20 or 30 amp devices with 90 C terminals.

Show me a one and make me believe. :D

All the ones I see are 75 C max.
 
Re: 110.14(C) - Temperature Limitations at Connections

Mc5w

"Standard locking receptacles rated 20 or 30 amperes have 90 Celsius capable terminals so that there are no problems with wiring that is embedded in thermal insulation. This allowed me to have 9 rather than 6 current carrying conductors in a conduit in the trench."

I am not sure where you read the 90 degree C on those devices, like Bob I would love to see that information.
 
Re: 110.14(C) - Temperature Limitations at Connections

Originally posted by mc5w:
You also forgot a few things:

1. Derating for 4 or more conductors.

...
Second sentence of the new proposed 110.14(C)(1):
Unless marked otherwise , the conductor ampacity at a connecting device or equipment terminal shall be based on Table 310.16 without further adjustment except as required by the appropriate ambient correction factor of the conductor.
This is already the basic UL requirement; however, the number of connections is not the scope of this Subsection anyway. The termination temperature limitation is a point phenomenon at the termination itself("at a connecting device or equipment terminal"). Most terminals are presumed to connect not more than 1 conductor per UL; and connectors not more than 2, "unless marked otherwise."

In addition, to cover your other issues, the new 110.14(C)(1)(a)(3) and 110.14(C)(1)(b)(3) note the host equipment must also be identified to use higher rated conductors. This has also always been the UL requirement.

Please re-read the original and revised Substantiations. The conductor's own temperature limitations, created by its own insulation, are appropriately covered in Art 310.

Forum Note: A Proposal must always be evaluated in context of its Substantiation; the TCs and CMPs do.
 
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