Sub Panel Inspection

[slush]

I had my sub panel inspection earlier this week. For reference, my sub panel is 200' away from the main panel, I pulled two hots, one neutral and a ground, all in proper conduit, buried to depth. When we walked out to the sub panel, he said I couldn't use the ground from the main panel and I had to remove it, and use the grounding rods I sank as the only ground. Everything I've read points to this as being incorrect, is it? He approved the installation, but I want to make sure it's done properly and with the greatest amount of safety as possible.



FYI: They are using 2014 NEC


Thanks

 

[slush]

Forgot to add, the bonding screw is removed.

 

[NWOhioChevyGuy]

My understanding "here" in my area

Attached structure - grounded back to Main
Detached structure - separate grounds at Sub

They use a newer NEC here, don't recall what revision.

 

[Norcal]

Inspector is incorrect.

 

[mcbane]

I believe your inspector is wrong unless there is a local amendment to NEC.

See NEC 250.32(B)(1)

"Supplied by a Feeder or Branch Circuit: An equipment grounding conductor, as described in 250.118, shall be run with the supply conductors and be connected to the building or structure disconnecting means and to the grounding electrode(s). The equipment grounding conductor shall be used for grounding or bonding of equipment, structures, or frames required to be grounded or bonded. The equipment grounding conductor shall be sized in accordance with 250.122. Any installed grounded conductor shall not be connected to the equipment grounding conductor or to the grounding electrode(s)."

Above text from 2017 NEC, but I believe this has been a requirement since early 2000s. There is an exception for previously installed feeders, so if you are replacing a panel at the detached structure you don't need to install a separate grounding conductor from the main panel.

 

[slush]

I believe your inspector is wrong unless there is a local amendment to NEC.

See NEC 250.32(B)(1)

"Supplied by a Feeder or Branch Circuit: An equipment grounding conductor, as described in 250.118, shall be run with the supply conductors and be connected to the building or structure disconnecting means and to the grounding electrode(s). The equipment grounding conductor shall be used for grounding or bonding of equipment, structures, or frames required to be grounded or bonded. The equipment grounding conductor shall be sized in accordance with 250.122. Any installed grounded conductor shall not be connected to the equipment grounding conductor or to the grounding electrode(s)."

Above text from 2017 NEC, but I believe this has been a requirement since early 2000s. There is an exception for previously installed feeders, so if you are replacing a panel at the detached structure you don't need to install a separate grounding conductor from the main panel.

Nope, new service. He even told me that I could pull the entire conductor out of the run (which I'm not going to do).

 

[pattenp]

I'll pile on by saying the inspector is clueless. What state are you in?

 

[u2slow]

The ground setup the inspector is allowing mimics what we used to do in Canada for buildings with livestock (especially sensitive to ground potential).

I don't see any hazard. There's a number of sound ways to do things and Code usually ends up picking one flavour.

 

[csp]

Code has required a separate ground conductor on sub-panels since 2008 IIRC, so using 2014 NEC would also include this requirement.

 

[pattenp]

The ground setup the inspector is allowing mimics what we used to do in Canada for buildings with livestock (especially sensitive to ground potential).

I don't see any hazard. There's a number of sound ways to do things and Code usually ends up picking one flavour.

I guess you missed that the OP said the bonding screw in the sub was removed. Earth ground is not good for clearing fault current.

 

[Terry D]

One more vote that the inspector does not have a clue. A sub panel has to have a equipment ground pulled from the panel it is fed from.

 

[u2slow]

I guess you missed that the OP said the bonding screw in the sub was removed. Earth ground is not good for clearing fault current.

Oops ya, missed that... what I was commenting would have the neutral bonded at the sub.

 

[andyvh1959]

Here in Green Bay I was required to connect a ground from the main panel to the sub panel feeding power to my new detached garage. Also, the detached garage required two ground rods (minimum six feet apart) connected to the ground bus bar. So the diagram the OP included agrees, with the exception of the 2nd ground rod.

 

[slush]

I'll pile on by saying the inspector is clueless. What state are you in?

Florida

 

[slush]

Here in Green Bay I was required to connect a ground from the main panel to the sub panel feeding power to my new detached garage. Also, the detached garage required two ground rods (minimum six feet apart) connected to the ground bus bar. So the diagram the OP included agrees, with the exception of the 2nd ground rod.

Sorry, that diagram doesn't show the second grounding rod. I did sink two 8' rods with greater than 6' apart.