Is it acceptable for feeder cables to a motor to be warm to the touch? The insulation is THHN, rated for 90 degrees C. The engineer had ordered a thermal scan, and the temperature on the cable surface was about 55 degrees C. The cables are really heating up the conduit, which doesn't seem right. Will the cable insulation be fine as long as the temperature is below the rating, even though it feels warm?
conductor temperature rating
- Thread starter joeymacs
- Start date
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- Location
- Logan, Utah
Welcome to the forum.
As long as the temperaure stays below the rating of the conductor it should be OK.
It is common for cables to be warm to the touch.
Chris
As long as the temperaure stays below the rating of the conductor it should be OK.
It is common for cables to be warm to the touch.
Chris
Volta
Senior Member
- Location
- Columbus, Ohio
I agree with Chris.
I assume this is newer work, but if it is older, and the insulation is a TW type, you may want to take its temperature in warmer weather, after long use, under full load, etc. as that older style is only rated for 60 deg C.
I assume this is newer work, but if it is older, and the insulation is a TW type, you may want to take its temperature in warmer weather, after long use, under full load, etc. as that older style is only rated for 60 deg C.
poeboy
Member
- Location
- Los Angeles Metro area
55 doesn't seem unusually warm for the conductors, however I think before answering the question I would ask how long is the run; are the conductors and OCP (and is the OCP fuses, CB, or something else?) sized correctly (also how many conductors in the raceway); and is there a VFD on the motor???
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