5 kV PT wire in a 15 kV ATS
5 kV PT wire in a 15 kV ATS
(OP)
We had a fault in an ATS last week. Upon inspection, we found that a wire in one of the cabinets had burned through and arced in a few places.
This is a 12.47 kV ATS (nominal 15 kV). The wires feeding the loads are large 15 kV rated cables. There are also smaller (#4) wires that feed the PT's. It looks like these are only rated at 5 kV.
So one of those cables was laying against the cabinet and after about a year of service, the insulation burned through.
I am being told by the manufacturer that these wires are allowed to be 5 kV rated and that the problem is faulty installation - not keeping the wires dressed so that they stay away from the frame.
I don't understand how it can possibly be acceptable to put 5 kV rated cable in a 15 kV compartment. Isn't that a code violation?
This is a 12.47 kV ATS (nominal 15 kV). The wires feeding the loads are large 15 kV rated cables. There are also smaller (#4) wires that feed the PT's. It looks like these are only rated at 5 kV.
So one of those cables was laying against the cabinet and after about a year of service, the insulation burned through.
I am being told by the manufacturer that these wires are allowed to be 5 kV rated and that the problem is faulty installation - not keeping the wires dressed so that they stay away from the frame.
I don't understand how it can possibly be acceptable to put 5 kV rated cable in a 15 kV compartment. Isn't that a code violation?






RE: 5 kV PT wire in a 15 kV ATS
Also, unshielded cable is used for medium-voltage wiring within switchgear enclosures. This is OK, but the cable has to be kept away from grounded surfaces. If the unshielded cable is resting on the surface of the metal enclosure, it can fail, even if it is 15 kV.
David Castor
www.cvoes.com
RE: 5 kV PT wire in a 15 kV ATS
I looked pretty hard and could not find a standard allowing this - has anybody else?
RE: 5 kV PT wire in a 15 kV ATS
RE: 5 kV PT wire in a 15 kV ATS
RE: 5 kV PT wire in a 15 kV ATS
RE: 5 kV PT wire in a 15 kV ATS
Isn't that like me putting in a 100A panel with 200A of load and telling the home owner to never run everything at once?
RE: 5 kV PT wire in a 15 kV ATS