Is there a reason to oversize medium voltage cables to motors other than temp and ampacity?
Is there a reason to oversize medium voltage cables to motors other than temp and ampacity?
(OP)
I'm on a project that is to replace a number of medium voltage cables to some motors. The motors operate at 4160V. The biggest motor is 500HP, 75Amps or so.
This is an emergency job. The existing cabling is #2/0, the engineering firm specified #2. It seems like they used the 1.25 rule per the NEC which doesn't apply to our situation.
They have the coordination study which I would assume they used to size this...but I'm telling our guy not to get something smaller that what was there - as its no sweat on us, but could if that's too small.
Is this being over cautious? This is at a power plant.
This is an emergency job. The existing cabling is #2/0, the engineering firm specified #2. It seems like they used the 1.25 rule per the NEC which doesn't apply to our situation.
They have the coordination study which I would assume they used to size this...but I'm telling our guy not to get something smaller that what was there - as its no sweat on us, but could if that's too small.
Is this being over cautious? This is at a power plant.






RE: Is there a reason to oversize medium voltage cables to motors other than temp and ampacity?
a) Excessive voltage drop during starting
b) Excessive voltage drop during running
c) Excessive de-rating
d) Mechanical strength
c) Minimum available size for the MV cables
RE: Is there a reason to oversize medium voltage cables to motors other than temp and ampacity?
RE: Is there a reason to oversize medium voltage cables to motors other than temp and ampacity?
"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington
RE: Is there a reason to oversize medium voltage cables to motors other than temp and ampacity?
RE: Is there a reason to oversize medium voltage cables to motors other than temp and ampacity?
RE: Is there a reason to oversize medium voltage cables to motors other than temp and ampacity?