Cable temperature ratings and Ampacity

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Pitt123

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I was looking at a spec sheet today for a piece of 2kV cable we are looking to purchase, and noticted that on the spec sheet it had ampacities listed for temperature categories of 110deg, 100deg, and 95deg. Since the terminals we are connecting these to are only rated for 75deg, can we use the ampacity ratings listed for the temps above? Why would there not be a 75deg C rating? Or does the 75deg rating only apply to 600V rated cable?
 

kingpb

Senior Member
I was looking at a spec sheet today for a piece of 2kV cable we are looking to purchase, and noticted that on the spec sheet it had ampacities listed for temperature categories of 110deg, 100deg, and 95deg. Since the terminals we are connecting these to are only rated for 75deg, can we use the ampacity ratings listed for the temps above? Why would there not be a 75deg C rating? Or does the 75deg rating only apply to 600V rated cable?

MV cable temperatures are higher, i.e. MV 90 and MV 105. You will need to check specifcally for your equipment, but I believe MV equipment, in general, is rated 90 deg C not 105 deg C. The 105 Deg rating can be used for derating, similar to LV cable at 75 and 90 deg C.
 
If I understand 110.14 correctly, unless your lugs are marked otherwise, you are limited to 310.16 75C or 60C columns. You can use the higher temp ampacities for derating purposes.

I do understand what you are refering to the Art 110.14 however as the OP mention meduim voltage cable and the med voltage cable have diffrent rating than stanard run of mill cables.

Merci,Marc
 
The type W cable I use in marinas is 2KV rated. Can you show me a code reference that exempts me from being held to 110.14 if I use this cable?


Unforetally I do not have the 2008 NEC code book with me at the moment due I am at my second home in France but I will find the answer one way or other..

Now speaking of type W cable it is typical to be dual rated for both 600 volt and 2400 volt class but not always the case so check the cable it will stamp the voltage class in there.

Now for termations for low voltage class as you refering to this one { under 600 volts } we just follow by termation tempture per manufacter device it will be ulitized { used } most common useally are either 60?C or 75?C

But a nice twist with meduim voltage class I know some of electrical contractors will use the standard termations.

Merci,Marc
 
Hardworkingstiff.,

I did get a chance to check it out and it did say noting at all however I did found one part with med voltage spices { this part I did found in my old NEC code book ( it is printed in French ) so I will traslated to Engish

"On permettra aux conducteurs de n'?tre terminnated bas? sur le 90?C l'?valuation de temp?rature et ampacity ? moins qu'autrement indentified "

" Conductors shall be permitted to be terminnated based on the 90?C temperature rating and ampacity unless otherwise indentified "

This part is only used in med/ high voltage otherwise indentifed.

Merci,Marc
 
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