600 amp service install

T

Therealcrt

Senior Member
Location
Kansas City
Occupation
Electrician
Gonna be doing a new 600 amp service install at a warehouse,service feeders from transformer to A CT cabinet from my CT cabinet to the tenants. Space. I’m gonna be pulling aluminum so I figured 500 is good for 310 at 75°C so I’ll be running parallel 500 each set in a 3 inch conduit three phase 480 V

I just have a few questions. When are the use of bonding bushings required do I need to use them in my CT cabinet if the voltage is 277 or greater to ground whether or not I use a whole punch or a concentric/eccentric knockout since it’s at the service.

Also, I believe I’m gonna be using window current transformers I’ve done them before and I always remember that the white dot that’s painted on there faces the primary side, but I’ve seen various rules as far as I have to remove the mounting bracket on the back is that specific to the AHJ or is that common and also is there a manual that comes with those CT’s that state that I must do that?
 
If the metal service raceways are ahead of the service disconnect then a bonding bushing or other means beyond the standard locknuts is required on one end to bond the raceways. If there are no concentric or eccentric KO's then a bonding locknut is sufficient. If there are concentric or eccentric KOs then the bonding bushing would be required. CTs should fall under the rules of the POCO.
 
So the raceways from the CT enclosure to the service disconnect need to be bonded at either side? Probably inside the CT cabinet. Why not both sides
 
Eddie702 said:
The neutral will bond the service enclosure and the CT cabinet. The bonding bushing bonds the nipple so no need to do that on both ends.
Click to expand...
What Eddie said. The bonding of the metal raceway is not there to provide continuity across the two pieces of equipment it's merely ensuring that the metal raceway is properly bonded.
 
Just make sure you understand your utility company rules...ours requires metal conduits that contain service conductors to be bonded at both ends. Yes, I know that that is covered by the NEC and the NEC does not require both ends to be bond, but the utility does and if you want your power connected, you will bond both ends.
 
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