To avoid these ads, REGISTER NOW!

Rewiring subpanel, grounding electrode\utility pole conflict?

MetalSlug

Active member
Joined
Nov 10, 2015
Messages
25
Hello all

So I got a 5hp, 80gal. Champion compressor from work earlier in the year but have yet to hook it up because the wiring to my garage is only 10 ga. I'm finally getting around on planning out rewiring and am thinking of running 6 ga. Wire, but when I looked at the sub panel, I realized it is not properly grounded. Neutral all go to neutral bus bar and it has a ground wire connecting the neutral bus bar to main panel ground. There are no grounding wires for anything in the garage (grounded through metal conduit), but at this point I guess it doesn't matter since the panel isn't grounded to earth anyway (uploaded pic of panel wiring and outlet tester showing ok reading).

So at this point, I've got added work to do to make this right and will be running conduit along the foundation edge of the garage (don't really care to hide behind drywall) to run a grounding wire to a grounding rod(s) that I will need to pound into the ground behind the garage, but there is a utility pole back there with it's own grounding conductor.

My question is do I need to be 6 feet from the utility pole as I would with a second grounding rod or is it going to be fine putting a grounding conductor within 6 feet of the utility pole. I can't really put it anywhere else without removing a tree stump further down the path (background of utility pole pic) as the rest of the area around garage already has cement\asphalt.

By the way, it is a detached garage with sub panel about 50 feet from main panel in City of Los Angeles.
 

Attachments

  • IMG_20151113_191351.jpg
    IMG_20151113_191351.jpg
    142 KB · Views: 50
  • IMG_20151109_170340.jpg
    IMG_20151109_170340.jpg
    118.9 KB · Views: 35
  • IMG_20151109_170422.jpg
    IMG_20151109_170422.jpg
    114.5 KB · Views: 32
  • IMG_20151114_145631.jpg
    IMG_20151114_145631.jpg
    151.7 KB · Views: 36
Last edited:
To avoid these ads, REGISTER NOW!
OP
M

MetalSlug

Active member
Joined
Nov 10, 2015
Messages
25
I see no reason you cant be close to the pole

Ok, I was unsure if it had to be away from grounding conductors in general since two grounding rods have to be 6 feet apart.


If you dont have access to a second ground source like a copper water line Id install 2 ground rods outside.;)

The plan is to install 2 rods, but just not sure if I could put one of them within a couple feet from a utility pole that is grounded to earth behind my garage.
 
To avoid these ads, REGISTER NOW!

wyliesdiesels

Well-known member
Joined
Aug 14, 2012
Messages
20,022
Location
Modesto, CA
Hello all

So I got a 5hp, 80gal. Champion compressor from work earlier in the year but have yet to hook it up because the wiring to my garage is only 10 ga. I'm finally getting around on planning out rewiring and am thinking of running 6 ga. Wire, but when I looked at the sub panel, I realized it is not properly grounded. Neutral all go to neutral bus bar and it has a ground wire connecting the neutral bus bar to main panel ground. There are no grounding wires for anything in the garage (grounded through metal conduit), but at this point I guess it doesn't matter since the panel isn't grounded to earth anyway (uploaded pic of panel wiring and outlet tester showing ok reading).

So at this point, I've got added work to do to make this right and will be running conduit along the foundation edge of the garage (don't really care to hide behind drywall) to run a grounding wire to a grounding rod(s) that I will need to pound into the ground behind the garage, but there is a utility pole back there with it's own grounding conductor.

My question is do I need to be 6 feet from the utility pole as I would with a second grounding rod or is it going to be fine putting a grounding conductor within 6 feet of the utility pole. I can't really put it anywhere else without removing a tree stump further down the path (background of utility pole pic) as the rest of the area around garage already has cement\asphalt.

By the way, it is a detached garage with sub panel about 50 feet from main panel in City of Los Angeles.

Using the metal conduit as the EGC is code permissable.

Second, i think youre confused about EGCs and grounding electrodes(ie rods). They are 2 different animals. For a feeder to a garage, u need both.

3-wire feeds use to be allowed for detached structures. Starting with the 2008 code cycle, 4-wire feeds are required as well as 2 grounding electrodes.

The neutral bus bar in the subpanel needs to be isolated!

This is a good read and should clear up any confusion:

http://www.electriciantalk.com/articles/the-confusion-of-the-term-grounding/

1962d1199122169-detached-garage-sub-panel-grounding-q-4-wire-subpanel-detached.jpg


Looking at your subpanel, the only thing missing is a ground bar.

The neutral bus is NOT bonded. The bonding strip is removed from the neutral bar.

I see an EGC coming from the same conduit as the feeder amd goes to the neutral bar which is incorrect.

Im curious how u have proper grounding on your outlets when the neutral bar is isolated. Is the conduit feeding the panel metal?

What brand of panel is that? I see both challeneger and murray breakers.

Does this utility pole feed your service?
 
Last edited:
OP
M

MetalSlug

Active member
Joined
Nov 10, 2015
Messages
25
Using the metal conduit as the EGC is code permissable.

I've been reading about this and was under the impression flexible metal conduit was not acceptable as an EGC as lock nuts could corrode over time or someone could replace a metal connection with a pvc piece, and thus not allow a path in the case of an electrical fault, thus requiring a separate conductor to be run (green or bare wire in conduit). This isn't the case for me, but I didn't know it was code permissible.

Second, i think youre confused about EGCs and grounding electrodes(ie rods). They are 2 different animals. For a feeder to a garage, u need both.

Sorry, I knew that, just not the terminology so I can see how it looks wrong when I type it out and using "grounded" and "grounding" have two completely different meanings.

I have EMT going to the garage from main panel, but it also has a 4 wire feed with neutral and green wire egc both going to isolated neutral bus in subpanel.

3-wire feeds use to be allowed for detached structures. Starting with the 2008 code cycle, 4-wire feeds are required as well as 2 grounding electrodes.

Mine is 4 wire, but both white neutral and green conductor wire screwed into isolated bus bar in subpanel (checked that it is isolated, not bonded to panel with screw). Guess the real EGC is just the EMT going from sub panel to main panel 50 feet away. However, there are currently no grounding electrodes.


The neutral bus bar in the subpanel needs to be isolated!
Yup

This is a good read and should clear up any confusion:

http://www.electriciantalk.com/articles/the-confusion-of-the-term-grounding/
Thanks, that helped with the terminology


1962d1199122169-detached-garage-sub-panel-grounding-q-4-wire-subpanel-detached.jpg


Looking at your subpanel, the only thing missing is a ground bar.

Yes

The neutral bus is NOT bonded. The bonding strip is removed from the neutral bar.

I asked my neighbor who is a contractor and according to him, originally an electrician by trade, he said I should bond the strip to the neutral bus and scoffed at my suggestion that I needed at least one grounding electrode. I respectfully let him finish talking, but will not be seeking his help on this after all that.

I see an EGC coming from the same conduit as the feeder amd goes to the neutral bar which is incorrect.

Yup

Im curious how u have proper grounding on your outlets when the neutral bar is isolated. Is the conduit feeding the panel metal?

All conduit from outlets and receptacles in garage to sub panel is flexible metal and none are corroded and all connections are secure. Sub panel and main panel are connected through EMT conduit, so I would guess that the conduit between the two is currently acting as the EGC. I live in Los Angeles, so corrosion is not usually an issue with metal conduit here

What brand of panel is that? I see both challeneger and murray breakers.
Yes, I was wondering about that as well since most of what I've read online suggests they should all be the same brand.

Panel brand is Murray


Does this utility pole feed your service?
Yes, which is why I am unsure of placing a grounding electrode within in a couple feet of this pole
See all bold above:)
 

wyliesdiesels

Well-known member
Joined
Aug 14, 2012
Messages
20,022
Location
Modesto, CA
FMC/greenfield use to be allowed to be used as the EGC. Since your install is existing, it would be grandfathered in if it was done when code allowed it.

Yes Since u have metal conduit for the feeder, the conduit is acting as the EGC and the green wire is not necessary. Clearly whoever wired this didnt know what they were doing. They couldve ommitted the green wire and added a ground bar. When was this wiring done?

Your neighbor doesnt know what hes talking about. Yes bonded neutrals in subs in detached structures used to be allowed but not anymore. U have a 4-wire feed so none of this matters. And grounding electrodes have ALWAYS been required for detached structures.

Remove the challenger breakers and put in murrays! U will be glad u did!

BTW if u will have more than 6 breaker handles, u will need a main disconnect.

Since the PoCo's rod is connected to your service, i would make sure your rods are at least 6' away. But Im not aware of any code that mandates this.
 
Last edited:
OP
M

MetalSlug

Active member
Joined
Nov 10, 2015
Messages
25
FMC/greenfield use to be allowed to be used as the EGC. Since your install is existing, it would be grandfathered in if it was done when code allowed it.

Yes Since u have metal conduit for the feeder, the conduit is acting as the EGC and the green wire is not necessary. Clearly whoever wired this didnt know what they were doing. They couldve ommitted the green wire and added a ground bar. When was this wiring done?

Your neighbor doesnt know what hes talking about. Yes bonded neutrals in subs in detached structures used to be allowed but not anymore. U have a 4-wire feed so none of this matters. And grounding electrodes have ALWAYS been required for detached structures.

Remove the challenger breakers and put in murrays! U will be glad u did!

BTW if u will have more than 6 breaker handles, u will need a main disconnect.

Since the PoCo's rod is connected to your service, i would make sure your rods are at least 6' away. But Im not aware of any code that mandates this.

I moved in 2 years ago and noticed most things were replaced or remodeled most likely in the mid to late 90's and a lot of it had been done by the owner with Home Depot or Sears products. The same neighbor says he did the garage wiring and updated the main panel to 200A service. Not sure if he's telling the truth or not as the main panel looks to be done properly.

I might end up with more than 6 breakers, so if that means I need a main disconnect then I guess I should just start fresh and just get a new Sub panel box that has as a provision for a main disconnect breaker instead of putting in another box just for that. I'll have to see if I can put more outlets or lights on fewer breakers since I bet some don't even use more than 3-4 amps.

Guess to be 100% on the grounding electrodes next to the utility pole, I should just call the utility. Just stinks because anything city govt. related in Los Angeles takes hours and being bounced around just to get one question answered.:mad:

Thanks for all the extra info, it has definitely been educational :beer:
 
To avoid these ads, REGISTER NOW!
Top Bottom