Generator grounding

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hhsting

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I have outside generator located 30 feet away from building that’s separately derived. It’s on a pad and concrete encased electrode per NEC 2014 Section 250.53(A)(3) which can be used as qualified electrode however do I also need to provide additional or just one GEC to water pipe underground or building steel which is about 30 feet away in building?
 
hhsting said:
I have outside generator located 30 feet away from building that’s separately derived. It’s on a pad and concrete encased electrode per NEC 2014 Section 250.53(A)(3) which can be used as qualified electrode however do I also need to provide additional or just one GEC to water pipe underground or building steel which is about 30 feet away in building?
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I'd say you need an EGC between the generator and the service grounding through whatever equipment is in the pathway.
 
I do not accept a floating pad as being a footing or foundation, so no matter how much rebar is in it, it is not a grounded electrode as far as I am concerned.
 
don_resqcapt19 said:
I do not accept a floating pad as being a footing or foundation, so no matter how much rebar is in it, it is not a grounded electrode as far as I am concerned.
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Um I cannot do that don_resqcapt19. If the concrete encased electrode is in compliance with NEC 2014 section 250.52(A)(3) then it’s qualified.

However NEC 2014 section 250.30(A)(4) says first do steel or water pipe and if they are not available then do other electrodes. My concern is water pipe or steel are inside building 30 feet away. So which grounding electrode one use?
 
hhsting said:
I have outside generator located 30 feet away from building that’s separately derived. It’s on a pad and concrete encased electrode per NEC 2014 Section 250.53(A)(3) which can be used as qualified electrode however do I also need to provide additional or just one GEC to water pipe underground or building steel which is about 30 feet away in building?
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I have read this at least eight times and I can't figure out what it is you are asking.

A concrete pad is not a qualifying grounding electrode.

Why would you need to connect to a water pipe that is underground?

What does "building steel which is about 30 feet away in building" mean?
 
ActionDave said:
I have read this at least eight times and I can't figure out what it is y
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Sorry but main question is as follows:

NEC 2014 section 250.30(A)(4) says first do steel or water pipe grounding electrodes for separately derived system and if they are not available then do other electrodes. Outside generator is 30 feet away from building and I do have water pipe or steel but they are inside building 30 feet away.

I have generator concrete pad right at the generator that qualifies as concrete encased electrode.

I have plans that show the generator concrete pad with concrete encased electrode used as grounding electrode. No GEC to steel or water pipe 30 feet away. However I am not sure if it complies with NEC 2014 Section 250.30(A)(4) which says to first use steel or water pipe.


So which grounding electrode one use inside building 30 feet away or concrete encased electrode to satisfy NEC 2014 Section 250.30(A)(4)?
 
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.
 
hhsting said:
Sorry but main question is as follows:

NEC 2014 section 250.30(A)(4) says first do steel or water pipe grounding electrodes for separately derived system and if they are not available then do other electrodes. Outside generator is 30 feet away from building and I do have water pipe or steel but they are inside building 30 feet away.I have generator concrete pad right at the generator that qualifies as concrete encased electrode.

I have plans that show the generator concrete pad with concrete encased electrode used as grounding electrode. No GEC to steel or water pipe 30 feet away. However I am not sure if it complies with NEC 2014 Section 250.30(A)(4) which says to first use steel or water pipe.


So which grounding electrode one use inside building 30 feet away or concrete encased electrode to satisfy NEC 2014 Section 250.30(A)(4)?
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If I remember correctly there’s no burial depth on an grounding electrode conductor, someone correct me if I am wrong.So you could scratch a path over to a for sure qualifying grounding electrode.
As far as the small concrete pad being a grounding electrode.. I’m sure opinions probably will vary. After reading Larryfines comment, I myself (opinion) simply just grab some rods.
 
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In my opinion, the feeder EGC is all that's needed between the genny and the building.

If the pad as an Ufer is a concern, as it has no footing, add a rod.
 
EGC is all thats needed on normal generator installs unless it is a stand alone SDS or an SDS where you are switching the neutral. I think Generac even changed their manuals to say it can be done but it is no longer required as they were burning up boards faster on installs with ground rods at the generator.
 
SSDriver said:
EGC is all thats needed on normal generator installs unless it is a SDS where you are switching the neutral. I think Generac even changed their manuals to say it can be done but it is no longer required as there were burning up boards faster on installs with ground rods at the generator.
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Generator is SDS with ATS neutral switched. Please see post#1


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hhsting said:
Generator is SDS with ATS neutral switched.


Sent from my iPhone using Tapatalk
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I was just updated my wording (editing) on my post to clarify. That was my intent of it being a SDS(that it must have a switched neutral) other wise the generator tied in with a non switched neutral would not be a SDS and not require the ground rod.
 
hhsting said:
Um I cannot do that don_resqcapt19. If the concrete encased electrode is in compliance with NEC 2014 section 250.52(A)(3) then it’s qualified.
...
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It is my opinion that a floating slab is not a foundation or footing, and therefore is not a concrete encased electrode per the requirements of the NEC.
 
So you have a system bonding jumper at the generator and you are using a transfer switch that switches the neutral?
Is there a breaker at the generator?
 
hhsting said:
Do you think generator concrete pad would be structure or not with generator on it according to NEC 2014?
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It doesn't matter if it is a structure. A concrete encased electrode can only be in a footing or a foundation...a floating slab is not a footing or a foundation.
 
hhsting said:
Yes generator has main breaker all in one enclosure
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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.
 
hhsting said:
Do you think generator concrete pad would be structure or not with generator on it according to NEC 2014?
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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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