Generator grounding

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don_resqcapt19 said:
If it was my project, I would eliminate the breaker at the generator and run the circuit along with a supply side bonding jumper to a OCPD at the building, install the system bonding jumper at the OCPD and connect to the existing building grounding electrode system.
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It’s not my project either I am only plan reviewer and that’s a design issue
 
I've seen inspectors enforce it different ways. If your concrete encased electrode at the pad qualifies then most allow that as the generator electrode, however, since the building is only 30 ft away I have seen inspectors require the the connection be made to the building system. You AHJ needs to make the call.
 
augie47 said:
I would not think so. Not much more than the slab an HVAC unit might sit on.
Only advantage is if it has a footer & rebar fitting NEC requirements you have your electrode.
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How do I know if it has a footer? Not a structural person so not sure. See attached. The arrow point to generator concrete pad says has 20 ft zinc galvanized coated copper rod of 3/4 inch in diameter.

a442d245481dafcb7ea90e59298cb5a4.jpg
 
Without some engineering testing for grounding you don't know unless you observed the pour.\
IMO., not worth the time or effort. If the AHJ does not require connection to the building electrodes, drive two ground rods and connect to your footer ground for good measure.
 
augie47 said:
IMO, if the generator is 30ft from the building and you have a grounding electode at the generator you only need to worry about using that electrode.
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Agree the generator is away from the primary building and is it's own separate building or structure and needs it's own separate GES just like a garage at same location would require it's own GES. Water pipe or structural steel in a separate building means nothing to any required GES at the generator location.
 
augie47 said:
Without some engineering testing for grounding you don't know unless you observed the pour.\
IMO., not worth the time or effort. If the AHJ does not require connection to the building electrodes, drive two ground rods and connect to your footer ground for good measure.
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I might just say to designer connect to grounding electrode in building either water pipe or steel whichever closest.
 
kwired said:
Agree the generator is away from the primary building and is it's own separate building or structure and needs it's own separate GES just like a garage at same location would require it's own GES. Water pipe or structural steel in a separate building means nothing to any required GES at the generator location.
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Please see Post #20 generator with main breaker in pad maybe not structure ????
 
hhsting said:
Please see Post #20 generator with main breaker in pad maybe not structure ????
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Post 20 isn't about whether it is a structure or not it is about whether there is a qualifying CEE or not at the location in question.

Is possible this is not a building or structure, if so a GES isn't required. If a GES is required and you have no qualifying CEE, no water pipe or building steel, then you must install a "made electrode(s)" most popular choice being a rod(s).
 
kwired said:
Post 20 isn't about whether it is a structure or not it is about whether there is a qualifying CEE or not at the location in question.

Is possible this is not a building or structure, if so a GES isn't required. If a GES is required and you have no qualifying CEE, no water pipe or building steel, then you must install a "made electrode(s)" most popular choice being a rod(s).
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But if it's an SDS, it needs a GES regardless of if it's a structure.
 
kwired said:
Post 20 isn't about whether it is a structure or not it is about whether there is a qualifying CEE or not at the location in question.

Is possible this is not a building or structure, if so a GES isn't required. If a GES is required and you have no qualifying CEE, no water pipe or building steel, then you must install a "made electrode(s)" most popular choice being a rod(s).
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Only auguie can say post#20. Generator is SDS

However NEC 2014 Section 250.50:

“250.50 Grounding Electrode System. All grounding electrodes in 250.52(A)(1) through (A)(7) that are present at each building or structure served shall be bonded together ...”

NEC 2014 250.30(C):
“(C) Outdoor Source. If the source of separately derived system is located outside the building or structure supplied, a grounding electrode connection shall be made at the source location to one or more grounding electrodes in compliance with 250.50. In addition, the installation shall comply with 250.30(A) for grounded systems....”

Outside generator is serving the building Not the pad that it sits on. NEC 2014 Section 250.50 quoted above it would be grounding electrodes at building served Not the electrodes where generator is at since generator is Not serving the location where it sits on. Yes or no all your opinions please?
 
electrofelon said:
But if it's an SDS, it needs a GES regardless of if it's a structure.
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True, and that makes you treat it like a structure for this purpose even if not otherwise defined as one. Connect to all available electrodes that are available at the structure per 250.50. OP description seems to indicate there are no existing qualifying electrodes, therefore he must add one from 250(A)(4) through (A)(8). Rod(s) is typically most popular option.
 
kwired said:
True, and that makes you treat it like a structure for this purpose even if not otherwise defined as one. Connect to all available electrodes that are available at the structure per 250.50. OP description seems to indicate there are no existing qualifying electrodes, therefore he must add one from 250(A)(4) through (A)(8). Rod(s) is typically most popular option.
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Ok did you notice what I wrote post#32? NEC 2014 section 250.50, 250.30(C) says provide connection from generator to grounding electrodes at building or structure served.

Generator is serving the building not the pad it sits on. So even If there are qualifying grounding electrodes at the pad or at the generator you are suppose to provide grounding electrode connection from generator to the building electrodes since that’s where generator is serving.


Anyone else here disagree or agree?
 
electrofelon said:
Where are you getting that from, It does not say that.
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NEC 2014 Section 250.50:

“250.50 Grounding Electrode System. All grounding electrodes in 250.52(A)(1) through (A)(7) that are present at each building or structure SERVED shall be bonded together ...”

NEC 2014 250.30(C):
“(C) Outdoor Source. If the source of separately derived system is located outside the building or structure supplied, a grounding electrode connection shall be made at the source location to one or more grounding electrodes in compliance with 250.50. In addition, the installation shall comply with 250.30(A) for grounded systems....”


See above quoted from NEC 2014. Yes it does
 
hhsting said:
NEC 2014 Section 250.50:

“250.50 Grounding Electrode System. All grounding electrodes in 250.52(A)(1) through (A)(7) that are present at each building or structure SERVED shall be bonded together ...”

NEC 2014 250.30(C):
“(C) Outdoor Source. If the source of separately derived system is located outside the building or structure supplied, a grounding electrode connection shall be made at the source location to one or more grounding electrodes in compliance with 250.50. In addition, the installation shall comply with 250.30(A) for grounded systems....”
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Wouldn't that be at this separate structure/questionable non structure?

If it were just 5 or even 10 feet from the building being served, it is somewhat valid to consider it to be part of that building, but 30 feet away is getting into it definitely being something separate whether deemed a building/structure or just equiment.
 
kwired said:
Wouldn't that be at this separate structure/questionable non structure?

If it were just 5 or even 10 feet from the building being served, it is somewhat valid to consider it to be part of that building, but 30 feet away is getting into it definitely being something separate whether deemed a building/structure or just equiment.
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The bolded part says make connection from generator outside to grounding electrode(s) in compliance with 250.50.

So you take GEC from generator outside to grounding electrodes 250.50.


Again generator serves the building. The generator does not serve this separate structure where it sits. You agree?

So then NEC 2014 section 250.50 says to bond grounding electrode at building or structure served.
 
hhsting said:
The bolded part says make connection from generator outside to grounding electrode(s) in compliance with 250.50.

So you take GEC from generator outside to grounding electrodes 250.50.


Again generator serves the building. The generator does not serve this separate structure where it sits. You agree?

So then NEC 2014 section 250.50 says to bond grounding electrode at building or structure served.
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Am I right or wrong above


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