Thanks for the help with this service to a 1000 HP motor. Original equipment had a customer-owned 2500 kVA transformer mounted to end of breaker cabinet through a bus cabinet. The main is a 3000 amp breaker that feeds both 1) a 2000 amp breaker to a 1000 HP motor and 2) a 200 amp breaker to other ancillary loads.
The equipment was moved to a new site with a utility-owned transformer (different primary voltage).This is a 480 volt wye service to the motor. About 45,000 amps available fault current at 480 volts.
The old transformer was cut loose from the end of the assembly. A new feed from utility 2500 kVA transformer was brought into the bus cabinet on the end where the old transformer bus bars used to terminate. The new feed is 8 paralleled 500 MCM cu cables per phase in 8 conduits. I do not know the ground size but you can see it in the pics.
From the transformer to main, I had the following concerns and want to know if they are valid or if there are others:
1) Were conduit bushings installed? Picture looked like wire had abrasions.
2) Is bus cabinet suitable for cables?
3) Is the part of bus previously used for bus termination/connection listed for cable termination and is it suitable for multiple and stacked terminations?
4) How is cable protected from sharp cabinet edges?
5) Is cable lashing/support being installed?
6) Is the bus rated to support cable under normal weight and during fault stress?
7) Is proper phase-phase and phase-ground spacing maintained?
8) Are cable ties suitable securing method for the varnish coated glass wrapping the terminations?
9) Does field modifying the equipment/bus void the UL listing and are field certifications required?
10) With the transformer being cut away, how is remaining thin metal and openings providing proper arc blast protection?
Pictures are: Original transformer disconnected and moved to side for shipping (you can see terminals coming from transformer and switchgear in foreground):
Another view of original transformer with switchgear in background:
Original transformer cut loose from skid and old bus jumpers laying in front:
New cable entry into bus cabinet. You can see where old transformer used to be mounted on left side where bus jumpers went through opening:
A view of cables coming in bottom of bus cabinet. Note the white rubber strip put on the cabinet frame to keep cable from rubbing on sharp edge.
Another view of cabinet and cables:
A view of the terminations with stacked lugs on each side. They used the old bus termination holes.
The equipment was moved to a new site with a utility-owned transformer (different primary voltage).This is a 480 volt wye service to the motor. About 45,000 amps available fault current at 480 volts.
The old transformer was cut loose from the end of the assembly. A new feed from utility 2500 kVA transformer was brought into the bus cabinet on the end where the old transformer bus bars used to terminate. The new feed is 8 paralleled 500 MCM cu cables per phase in 8 conduits. I do not know the ground size but you can see it in the pics.
From the transformer to main, I had the following concerns and want to know if they are valid or if there are others:
1) Were conduit bushings installed? Picture looked like wire had abrasions.
2) Is bus cabinet suitable for cables?
3) Is the part of bus previously used for bus termination/connection listed for cable termination and is it suitable for multiple and stacked terminations?
4) How is cable protected from sharp cabinet edges?
5) Is cable lashing/support being installed?
6) Is the bus rated to support cable under normal weight and during fault stress?
7) Is proper phase-phase and phase-ground spacing maintained?
8) Are cable ties suitable securing method for the varnish coated glass wrapping the terminations?
9) Does field modifying the equipment/bus void the UL listing and are field certifications required?
10) With the transformer being cut away, how is remaining thin metal and openings providing proper arc blast protection?
Pictures are: Original transformer disconnected and moved to side for shipping (you can see terminals coming from transformer and switchgear in foreground):
Another view of original transformer with switchgear in background:
Original transformer cut loose from skid and old bus jumpers laying in front:
New cable entry into bus cabinet. You can see where old transformer used to be mounted on left side where bus jumpers went through opening:
A view of cables coming in bottom of bus cabinet. Note the white rubber strip put on the cabinet frame to keep cable from rubbing on sharp edge.
Another view of cabinet and cables:
A view of the terminations with stacked lugs on each side. They used the old bus termination holes.