75deg and 90deg rating.
- Thread starter Deetz
- Start date
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ron
Senior Member
- Location
- New York, 40.7514,-73.9925
No. The equipment where the lugs are installed is listed at the 75 degree ampacity.
rlundsrud
Senior Member
- Location
- chicago, il, USA
Even if the code allowed it, the terminations at the OCPD would also need to be rated for 90?
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Not just the terminals. For instance you could have a 90C terminal but if the equipment (panelboard, e.g.)is rated 75C then you must use 75C
If you have substantial distance between source and load, you can transition from 75? to 90? at "some" distance from 75? equipment enclosures. A transition (enclosure, box, terminals, etc.) uses all 90? equipment. The "some" distance is not conventionally specified. Some say 4' minimum, others say 10'.... while everyone agrees greater is better.
Yes. Use the 90C wire at its 75 C. or 60C rating.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
You answered yes, but your additional comment says no to the question asked
A lot of equipment uses 90 deg lugs, but the entire assembly still only has a 75 deg rating (or 60).
A 90C wire has higher ampacity at 75C rating thanYou answered yes, but your additional comment says no to the question asked
A lot of equipment uses 90 deg lugs, but the entire assembly still only has a 75 deg rating (or 60).
a 75C wire but smaller and so cheaper.
Interesting. What have I been missing?
A 90? and 75? wire operating at the same level of current will be the same temperature where all other conditions are identical. Insulation rating has no bearing on terminal temperature limits.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
A 90C wire has a higher ampacity but if it is used at 75C then it is no different than using a 75C wire unless de-rating is involved.
FREEBALL
Senior Member
- Location
- york pa usa
You also have to size per circuit breaker terminal ratings, so wouldn't you would have to change breaker terminals also if they aren't rated 90 degree.
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
And the only way to change the terminal rating would be to change the breaker.
FREEBALL
Senior Member
- Location
- york pa usa
exactly:happyno: but your not gonna find a breaker with a 90degree rating so you size your conductor appropriately. My understanding is if the terminal is rated 90 degree then it needs less conductor to dissipate heat. If its rated lower then it needs more conductor to do this. This is how I understand 110.14c
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kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
The miniature plug on breakers are going to have fixed lugs in general, but your larger framed breakers may have lugs that can be easily changed. Of those many do have lugs that are rated 90 deg, but they are still attached to a unit that is rated 75 deg. You can commonly find this in safety switches with factory installed lugs as well.
That lug rating is a stand alone rating for the lug, it is still only good for whatever rating is for equipment it may be attached to. The label on such equipment trumps the lug marking.
That lug rating is a stand alone rating for the lug, it is still only good for whatever rating is for equipment it may be attached to. The label on such equipment trumps the lug marking.
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