Sierrasparky
Senior Member
- Location
- USA
- Occupation
- Electrician ,contractor
I have a project where the a HVAC compressor replacement unit for a building came in different than on the plans and what is existing. I have to tell the bad news. I am looking to see if I am correct first.:?
The wiring is 500MCM THW ( short distance 15' from the MSB so not a real big deal )
The conduit is inside.
The nameplate is MCA 405a 208 3 phase
MOCP 600a
So THW is rated at 70 deg C only 380a ( does not have a 90 deg rating)
Since it is less than the required MCA of 405a the wire must be up sized.
I don't think there is a next higher rule for MCA-
Am I correct?
The wiring is 500MCM THW ( short distance 15' from the MSB so not a real big deal )
The conduit is inside.
The nameplate is MCA 405a 208 3 phase
MOCP 600a
So THW is rated at 70 deg C only 380a ( does not have a 90 deg rating)
Since it is less than the required MCA of 405a the wire must be up sized.
I don't think there is a next higher rule for MCA-
Am I correct?