Disconnect and MB panel ground

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jjhoward

jjhoward

Senior Member
Location
Northern NJ
Occupation
Owner TJ Electric
Here is the situation:
200 amp, underground 3 wire service to a residence.
3 wires from the street land in a disconnect.

Greenfield with 3 conductors go from the disconnect to the main breaker panel.
Each end of the greenfield has a grounding bushing wtih #8 solid under the set screw to the ground bus in the respective box.

Another #4 copper wire (THHN) not in the greenfield is routed from disconnect ground bus to main breaker panel ground bus.

Must there be a ground in the greenfield from disconnect to main breaker panel?

This is an existing install at a home that is for sale and the AHJ is saying a ground wire must be installed IN the greenfield.
He has not supplied any code reference yet....

Thank you.
 
jjhoward said:
Here is the situation:
200 amp, underground 3 wire service to a residence.
3 wires from the street land in a disconnect.

Greenfield with 3 conductors go from the disconnect to the main breaker panel.
Each end of the greenfield has a grounding bushing wtih #8 solid under the set screw to the ground bus in the respective box.

Another #4 copper wire (THHN) not in the greenfield is routed from disconnect ground bus to main breaker panel ground bus.

Must there be a ground in the greenfield from disconnect to main breaker panel?

This is an existing install at a home that is for sale and the AHJ is saying a ground wire must be installed IN the greenfield.
He has not supplied any code reference yet....

Thank you.
Click to expand...

We need to know what code cycle you're under to answer that
 
We have a problem if at the panel the bonding screw is not removed. After the disconnect neutral and ground must be seperated

My guess is this was caught and that was the cure. Not sure if the ground could be ran on outside.
 
Jim W in Tampa said:
We have a problem if at the panel the bonding screw is not removed. After the disconnect neutral and ground must be seperated

My guess is this was caught and that was the cure. Not sure if the ground could be ran on outside.
Click to expand...



At first, I was thinking that it would be legal under 05 without the wire on the outside,,,but that's not true due to multiple metallic paths. So the fourth wire is definatley needed.

The question is,,,is it legal on the outside.

I've actually gotta read that one
 
This was installed and inspected in August 2005. Not sure what code cycle the town was using then. I think we should assume 2005 cycle.

The main breaker panel is wired correctly, neutrals are not connected to the enclosure (bonding screw NOT in place).

There is a ground bus in the box for the grounds.
 
jjhoward said:
This was installed and inspected in August 2005. Not sure what code cycle the town was using then. I think we should assume 2005 cycle.

The main breaker panel is wired correctly, neutrals are not connected to the enclosure (bonding screw NOT in place).

There is a ground bus in the box for the grounds.
Click to expand...
I would nicely ask him for code number. It seems bit sloppy but perhaps there was a wire fill issue
 
This installation PASSED inspection in 2005.

This inspector was at the house for kitchen work the home owner recently did, opened the panel and flagged it.

Not sure what the HO did get this inpsector so "interested" in his 2005 service upgrade.
 
Hard to respond not knowing what the inspector flagged it for. Could be many reasons.

How long is the FMC (greenfield)?

I suspect the flex is over 6'. I believe the EGC is allowed to be on the outside of the raceway. 250.102(E)
 
The FMC run is about 7'

I am waiting for the inspector to call me back.

If I get a code reference from him I will update you.

Does 250.96 (A) apply here with the bonded FMC serving as a grounding conductor?
 
Doesn't 250.102 (E) say the bonding jumper CANNOT exceed 6' when installed on the outside of the raceway?

The exception allows lengths greater than 6' at outside pole locations.

What is the exception referring to?
 
jjhoward said:
Doesn't 250.102 (E) say the bonding jumper CANNOT exceed 6' when installed on the outside of the raceway?

The exception allows lengths greater than 6' at outside pole locations.

What is the exception referring to?
Click to expand...

It starts out saying it cannot be longer than 6' if on the outside. then,,,IMO,,,the first exception after (e) allows you to do this, if he removed the bonding bushing jumper,(discard it) and landed the EBJ in the bushing, would meet the exception and be allowed to be longer than 6 ft and be on the outside.
 
Joe -- look at article 230.43 (15). The flex cannot be over 6'

230.43(15) Flexible metal conduit not over 1.8 m (6 ft) long or liquidtight flexible metal conduit not over 1.8 m (6 ft) long between raceways, or between raceway and service equipment, with equipment bonding jumper routed with the flexible metal conduit or the liquidtight flexible metal conduit according to the provisions of 250.102(A), (B), (C), and (E)
Click to expand...
 
Denis,
Sounds like 240.33 is saying that the service conductors cannot be routed in the flex longer than 6'.

The conductors from the meter to the disconnect are service conductors.

Are the conductors from the disconnect to the main breaker panel service conductors or feeders?

There is about 3' of flex from the meter to the disconnect.

Then there is about 7' (maybe 8') of flex from the disconnect to the MB panel.
 
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