Ground rod and sub-panel

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I need an opinion. I recently completed a small 100 amp residential service upgrade. SE cable enters main disconnect with feeder cable then traveling on to a service sub-panel about 50 feet away.
Grounding electrode conductor goes from the main disconnect to the water pipe, connected within 5 feet of where it enters the building. I drove a ground rod and connected that to the sub-panel (due to convienent location).
AHJ failed job saying that the ground rod needed to be connected directly back to the main disconnect, and could not be connected to the service sub-panel.
I pointed out 2008 NEC 250.64 (F-1) thinking that would cover me. Still, no.
Why is it OK to bond a ground rod to say, the water pipe, but it can't be run back to a service sub-panel? This inspector is very good, so I'm assuming I'm missing something here. Thanks.
 

augie47

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Location
Tennessee
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State Electrical Inspector (Retired)
250.24(A)(1) directs you as the where the grounding electrode conductor can originate.
 

Buck Parrish

Senior Member
Location
NC & IN
I need an opinion. I recently completed a small 100 amp residential service upgrade. SE cable enters main disconnect with feeder cable then traveling on to a service sub-panel about 50 feet away.
Grounding electrode conductor goes from the main disconnect to the water pipe, connected within 5 feet of where it enters the building. I drove a ground rod and connected that to the sub-panel (due to convienent location).
AHJ failed job saying that the ground rod needed to be connected directly back to the main disconnect, and could not be connected to the service sub-panel.
I pointed out 2008 NEC 250.64 (F-1) thinking that would cover me. Still, no.
Why is it OK to bond a ground rod to say, the water pipe, but it can't be run back to a service sub-panel? This inspector is very good, so I'm assuming I'm missing something here. Thanks.


Yes, F-1 is refering to any convienent location from the main service equipment.
 

A/A Fuel GTX

Senior Member
Location
WI & AZ
Occupation
Electrician
The inspector is correct. The GEC's must be connected to the grounded conductor at the first disconnect. Check out 250.64 (D) (2) and (3).
 

Dennis Alwon

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Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
The inspector is correct. The GEC's must be connected to the grounded conductor at the first disconnect. Check out 250.64 (D) (2) and (3).

I know you know this but just to be precise, the gec may also be connected at the meter to the grounded conductor as long as your power company has no rules against it.
 

augie47

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Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
250.24 Grounding Service-Supplied Alternating-Current Systems.
(1) General. The grounding electrode conductor connection shall be made at any accessible point from the load end of the service drop or service lateral to and including the terminal or bus to which the grounded service conductor is connected at the service disconnecting means.

POCO and local rules not withstanding.
 

Greg1707

Senior Member
Location
Alexandria, VA
Occupation
Business owner Electrical contractor
the gec may also be connected at the meter to the grounded conductor as long as your power company has no rules against it.[/QUOTE]

It has been mentioned on this forum many times that POCO does not want the GEC inside their meter. There are various devices available made to attach to the exterior of the meter can for common bonding of cable tv, telephone, etc. Are any of these devices appropriate for bonding GEC to meter can on the exterior?
 

Dennis Alwon

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Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
It has been mentioned on this forum many times that POCO does not want the GEC inside their meter. There are various devices available made to attach to the exterior of the meter can for common bonding of cable tv, telephone, etc. Are any of these devices appropriate for bonding GEC to meter can on the exterior?

Greg, it has been mentioned on this forum that SOME poco's don't want the GEC in the meter. In NC it is not an issue at all-- not yet anyway and it is my preferred install for the ground rod connection.
 
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augie47

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Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
the gec may also be connected at the meter to the grounded conductor as long as your power company has no rules against it.

It has been mentioned on this forum many times that POCO does not want the GEC inside their meter. There are various devices available made to attach to the exterior of the meter can for common bonding of cable tv, telephone, etc. Are any of these devices appropriate for bonding GEC to meter can on the exterior?[/quote]

Not here.
(One of the local POCO requires connection in their meter, so it is obviously a rule that varies from jurisdiction)
As far as the connection, we read 250.24 as requiring the GEC be connected to the grounded conductor or grounded conductor buss.
Any connection that requires the current to pass thru the can, such as with the devices you mention, is unacceptable.
 

Greg1707

Senior Member
Location
Alexandria, VA
Occupation
Business owner Electrical contractor
The OP stated he was bonding to the metal water pipe. Therefore, isn't the ground rod a supplemental electrode? Doesn't 250.53 D2 allow the GEC for the supplemental electrode to be bonded to any grounded service enclosure? Wouldn't the meter enclosure qualify as a grounded service enclosure?
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
The OP stated he was bonding to the metal water pipe. Therefore, isn't the ground rod a supplemental electrode? Doesn't 250.53 D2 allow the GEC for the supplemental electrode to be bonded to any grounded service enclosure? Wouldn't the meter enclosure qualify as a grounded service enclosure?
Good point and I can see that being allowed on the water supplemental electrode (only), but in the OPs case I believe he terminated at a subpanel.
 

Greg1707

Senior Member
Location
Alexandria, VA
Occupation
Business owner Electrical contractor
Good point and I can see that being allowed on the water supplemental electrode (only), but in the OPs case I believe he terminated at a subpanel.
Ok, would this setup be code compliant and also satisfy the POCO?

Meter on exterior of house. Three conductor SEC to service panel inside of house. GEC bonds service panel to water pipe.

Supplemental grounding electrode (ground rod) connected to exterior of metal meter can using some type of listed device.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
Obviously I can't answer for POCO.
Until you pointed out the wording in 250.53(D)(2) I would say not AHJ acceptable here as the GEC at the meter does not connect directly to the grounded conductor, but, after reading your reference, if one was assured that was the GEC to the supplemental water electrode, I would say compliant.
I will be interested in input from others.
 

Greg1707

Senior Member
Location
Alexandria, VA
Occupation
Business owner Electrical contractor
Larry, I have brought this issue up before. Is there a code compliant way to bond to the exterior of the meter can?
 
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