Service Entrance

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Duuuuug

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Service:
800Amp/480-277VAC/3PH/4W
Wire in two 4" Conduits:
2 Sets of 3-600MCM (L1,L2,L3) and 1-600MCM (N)
Service Entrance Main Breaker (MB):
Line Side:
Service Conduits enter the MB, grounding locknuts installed, bonding bushings installed and wired. GEC wired to grounding electrode.
Load Side:
About 6" long conduits from MB to the Panelboard (with isolated neutral) with L1,L2,L3,N (NO EGC ground wires) . Grounding Locknuts installed, bonding bushings installed but not wired. ALSO, another GEC goes directly from the panelboard ground terminal to the grounding electrode.

Just asking, does this sounds right?
Any comments would be appreciated.

[ June 02, 2005, 02:51 PM: Message edited by: Duuuuug ]
 
Re: Service Entrance

Just for clarity, there are neutrals in each of the line side conduits?

You didn't mention if the neutral was bonded?

GEC sized according to 250.66?

Bonding on the line of the service disconnect needs either bonding lock nuts or bonding bushings not both. Neither are required on the load side of the service disconnect unless there are concentric or eccentric KO's.

[ June 02, 2005, 03:43 PM: Message edited by: infinity ]
 
Re: Service Entrance

Infinity,
1. There is (L1,L2,L3,N) in each service entrance conduit.
2. Both service entrance neutral wires are bonded.
3. Both GEC's are sized per 250.66.

Rhetorical question....
Why didn't the contractor just run a 1/0 equipment grounding conductor with each set of 600MCM (L1,L2,L3,N)...instead of installing two grounding electrode conductors?
 
Re: Service Entrance

Rhetorical question....
Why didn't the contractor just run a 1/0 equipment grounding conductor with each set of 600MCM (L1,L2,L3,N)...instead of installing two grounding electrode conductors?
Click to expand...
If you're speaking about the load side of the service disconnect, one reason is that they are not required if you have a properly bonded metallic raceway.
 
Re: Service Entrance

Originally posted by Duuuuug:
Load Side:
About 6" long conduits from MB to the Panelboard (with isolated neutral) with L1,L2,L3,N (NO EGC ground wires) .
Click to expand...
That's legal, the conduits serve as the EGC.
Grounding Locknuts installed, bonding bushings installed but not wired.
Click to expand...
See 250.96 and 250.97, and take a glance at the text surrounding it. The bonding bushings need to be used (as in, with conductors), if the conduits they are on are entering through concentrics.

ALSO, another GEC goes directly from the panelboard ground terminal to the grounding electrode.
Click to expand...
This is a little silly, but legal. I wonder why they went to all the bother...?

What is the grounding electrode used?
What type of conduit are we dealing with?

Rhetorical question....
Why didn't the contractor just run a 1/0 equipment grounding conductor with each set of 600MCM (L1,L2,L3,N)...instead of installing two grounding electrode conductors?
Click to expand...
Now I'm confused. Are there 2 x 4" conduits with 600 MCM CU feeding the Main Disconnect, and then another 2 sets of 600 MCM CU feeding a panel on the load side of the disconnecting means? That's seems weird. Is there only one panel in the joint? :confused:

[ June 02, 2005, 06:54 PM: Message edited by: georgestolz ]
 
Re: Service Entrance

George,
The Utility feeds the Main Breaker through Two 4"-conduits. Each with 600MCM (L1,L2,L3,N)

The Main Breaker feeds the Panelboard through Two 6"-Long 4"-conduits. Each with 600MCM (L1,L2,L3,N).

The Main Breaker is mounted adjacent to the Panelboard.

All conduit is Rigid Steel Conduit

Driven Ground Rod is used.
Let me know if you need more info.
Thanks
 
Re: Service Entrance

What size bonding jumper is used on the line side of the service to the bonding bushings?

Is the GEC passing through metal raceways? If so, 250.64 will require bonding at each end.

[ June 03, 2005, 09:06 PM: Message edited by: ryan_618 ]
 
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