250.32(B)(1) Is Grounding Electrode Required

[prawlings1]

I recently had a detached garage built. The master electrician who supervised the wiring says no grounding electrode is required at the subpanel in the garage. He said that when he installed the electrodes at subpanels in the past that city inspectors made him remove them. With a concrete floor and concrete driveway in place adding a ground electrode will be a lot of work.

The subpanel has no master circuit breaker. The subpanel power comes from a two pole 125 amp circuit breaker located in the main panel of the house. The neutral and ground bus bars in the subpanel are isolated. There is a ground conductor; same size as the power conductors, that connects the ground bus in the main panel to the ground bus in the subpanel.

I am looking at NEC 2011 250.32(B)(1) and exhibit 250.19 and it clearly says that a grounding electrode is required. The electrician says that he thinks the requirement for the ground rod was eliminated in either 2014 or 2017, but I can't find any indication that this is so.

I assume that the ground rod is to improve lightning protection, but I would appreciate someone enlightening me on whether the electrode is still required and if it is why it is necessary.

Thank you

 

[roger]

The electrician is incorrect. A GE is required at detached buildings per 250.32(A) in the 2014 and 2017 codes. Even if it had changed odds are that the code cycle in place in your area would be applicable.

You are correct that is required for reasons spelled out in 250.4(A)(1)

Roger

 

[kwired]

I recently had a detached garage built. The master electrician who supervised the wiring says no grounding electrode is required at the subpanel in the garage. He said that when he installed the electrodes at subpanels in the past that city inspectors made him remove them. With a concrete floor and concrete driveway in place adding a ground electrode will be a lot of work.

The subpanel has no master circuit breaker. The subpanel power comes from a two pole 125 amp circuit breaker located in the main panel of the house. The neutral and ground bus bars in the subpanel are isolated. There is a ground conductor; same size as the power conductors, that connects the ground bus in the main panel to the ground bus in the subpanel.

I am looking at NEC 2011 250.32(B)(1) and exhibit 250.19 and it clearly says that a grounding electrode is required. The electrician says that he thinks the requirement for the ground rod was eliminated in either 2014 or 2017, but I can't find any indication that this is so.

I assume that the ground rod is to improve lightning protection, but I would appreciate someone enlightening me on whether the electrode is still required and if it is why it is necessary.

Thank you

A grounding electrode is required at your structure. It doesn't have to be a ground rod. Chances are high that you have qualifying electrode in the footings and it should have been used as an electrode.

 

[david]

The subpanel has no master circuit breaker. The subpanel power comes from a two pole 125 amp circuit breaker located in the main panel of the house.

Thank you

you mentioned the above but, you did not ask about this in your question

How many breakers to disconnect the feeder at the detached garage?

 

[kwired]

you mentioned the above but, you did not ask about this in your question

How many breakers to disconnect the feeder at the detached garage?

That is another potential code issue, has nothing to do with his question about grounding electrodes though.

 

[david]

That is another potential code issue, has nothing to do with his question about grounding electrodes though.

Your correct and i should have stayed on point, the disconnect has nothing to do with the question asked.

A grounding electrode is required at your structure. It doesn't have to be a ground rod. Chances are high that you have qualifying electrode in the footings and it should have been used as an electrode.

Re-bar not required here for the garage structure could very well be required for the OP in Texas

 

[kwired]

Your correct and i should have stayed on point, the disconnect has nothing to do with the question asked.



Re-bar not required here for the garage structure could very well be required for the OP in Texas

There are fiberglass reinforcement products starting to gain popularity also - no CEE exists if those are used unless you make your own CEE.

 

[LarryFine]

Agree. Electrode required for anything greater than a single circuit (even if MWBC). The panel makes the supply a feeder, not a branch circuit.

The main breaker is only required if there are more than six breaker handles.

 

[prawlings1]

Why is the Grounding Electrode Needed?

Why is the Grounding Electrode Needed?

Thank you to everyone who responded.

The NEC does not explain the reason for the various code requirements. That would make the book so big it would be unusable. Would anyone venture a guess about why this requirement was added to the code? I think the benefit is primarily for better lighting protection rather than to reduce electrocution risk.

I my situation there was no plan to use the rebar in the foundation or driveway for grounding so it is not readily accessible. I believe that it would be easier to drill a hole in the concrete and drive a ground rod. I'm not looking forward to this project.

Also, there are a lot more than 6 circuit breakers in the subpanel. The subpanel is a Square D QO panel and it wasn't designed for a master circuit breaker. Please refer me to the article in the code where this is required.

Thank you for taking time to share your expertise.

 

[roger]

Thank you to everyone who responded.

The NEC does not explain the reason for the various code requirements. That would make the book so big it would be unusable. Would anyone venture a guess about why this requirement was added to the code? I think the benefit is primarily for better lighting protection rather than to reduce electrocution risk.

Read 250.4(A)(1)

Roger

 

[kwired]

Thank you to everyone who responded.

The NEC does not explain the reason for the various code requirements. That would make the book so big it would be unusable. Would anyone venture a guess about why this requirement was added to the code? I think the benefit is primarily for better lighting protection rather than to reduce electrocution risk.

I my situation there was no plan to use the rebar in the foundation or driveway for grounding so it is not readily accessible. I believe that it would be easier to drill a hole in the concrete and drive a ground rod. I'm not looking forward to this project.

Also, there are a lot more than 6 circuit breakers in the subpanel. The subpanel is a Square D QO panel and it wasn't designed for a master circuit breaker. Please refer me to the article in the code where this is required.

Thank you for taking time to share your expertise.

If there is qualifying reinforcement in your footings, 250.50 says you must use it. changes in how this is worded a few years back came about because many weren't using it because it wasn't accessible when the electrician came along. The way it is worded now there is no exception on new construction, one needs to plan accordingly when installing footings or it becomes more difficult to comply.

All common single phase QO loadcenters for about 30 or so years have the ability to accept a main breaker if they were not factory installed. You need the QOM or QOM2 depending on if it is a 125 amp or less or 150 -225 amp panel. The 6 and 8 space loadcenters with a horizontal bus, can have a backfed breaker as a main and there is a retaining device designed to hold it in the far left spaces.

What code section applies for more than 6 breakers?- see 225.33 for buildings supplied by a feeder and 230.71 for buildings supplied by services.

 

[roger]

Thank you to everyone who responded.

The NEC does not explain the reason for the various code requirements. That would make the book so big it would be unusable. Would anyone venture a guess about why this requirement was added to the code? I think the benefit is primarily for better lighting protection rather than to reduce electrocution risk.

I my situation there was no plan to use the rebar in the foundation or driveway for grounding so it is not readily accessible. I believe that it would be easier to drill a hole in the concrete and drive a ground rod. I'm not looking forward to this project.

Also, there are a lot more than 6 circuit breakers in the subpanel. The subpanel is a Square D QO panel and it wasn't designed for a master circuit breaker. Please refer me to the article in the code where this is required.

Thank you for taking time to share your expertise.

In your first post you indicated an electrician was handling the work, is there a permit and inspector involved as well?

Roger

 

[prawlings1]

No Permit, Inspection or Inspector

No Permit, Inspection or Inspector

I need to get a copy of the 2017 NEC. My 2011 edition does not include 250.4(A)(1).

The area where I live is rural without many people so there is no requirement for a permit, there are no inspections and consequently no inspectors. Insurance companies that write home warranty policies have inspectors that inspect construction at various stages and when a building is sold there is a home inspection. In my opinion, the inspectors who do these inspections are generalists and they do not qualify as true electrical inspectors. That is the reason I am doing my own research to make sure that the work in compliance with the NEC.

The owner of the electrical contracting company that did the wiring is a master electrician with years of experience. I am a reluctant to question his work without reading the NEC and consulting with other experts.

I plan to add a master circuit breaker and ground electrode as suggested, but I may have it done by a different electrician.

I appreciate everyone's input.

 

[packersparky]

I need to get a copy of the 2017 NEC. My 2011 edition does not include 250.4(A)(1).

The area where I live is rural without many people so there is no requirement for a permit, there are no inspections and consequently no inspectors. Insurance companies that write home warranty policies have inspectors that inspect construction at various stages and when a building is sold there is a home inspection. In my opinion, the inspectors who do these inspections are generalists and they do not qualify as true electrical inspectors. That is the reason I am doing my own research to make sure that the work in compliance with the NEC.

The owner of the electrical contracting company that did the wiring is a master electrician with years of experience. I am a reluctant to question his work without reading the NEC and consulting with other experts.

I plan to add a master circuit breaker and ground electrode as suggested, but I may have it done by a different electrician.

I appreciate everyone's input.

250.4(A)(1) is in the 2011 NEC.

250.4 General Requirements for Grounding and Bonding.
The following general requirements identify what
grounding and bonding of electrical systems are required to
accomplish. The prescriptive methods contained in Article
250 shall be followed to comply with the performance requirements
of this section.
(A) Grounded Systems.
(1) Electrical System Grounding. Electrical systems that
are grounded shall be connected to earth in a manner that
will limit the voltage imposed by lightning, line surges, or
unintentional contact with higher-voltage lines and that will
stabilize the voltage to earth during normal operation.

 

[kwired]

I need to get a copy of the 2017 NEC. My 2011 edition does not include 250.4(A)(1).

The area where I live is rural without many people so there is no requirement for a permit, there are no inspections and consequently no inspectors. Insurance companies that write home warranty policies have inspectors that inspect construction at various stages and when a building is sold there is a home inspection. In my opinion, the inspectors who do these inspections are generalists and they do not qualify as true electrical inspectors. That is the reason I am doing my own research to make sure that the work in compliance with the NEC.

The owner of the electrical contracting company that did the wiring is a master electrician with years of experience. I am a reluctant to question his work without reading the NEC and consulting with other experts.

I plan to add a master circuit breaker and ground electrode as suggested, but I may have it done by a different electrician.

I appreciate everyone's input.

If he is not getting inspected he possibly is doing some things that are not in compliance with NEC and isn't even aware he is doing those things wrong. The items in question here are not extreme hazards in many people's opinion, but still are in the code and does enhance overall safety to some extent if you comply with code.