Detached garage panel - do I need a separate grounding rod?

[pgray007]

From some of my reading here, it seems I might need a separate growing rod in my detached garage.

The detached sits about 8-10 feet from the main house, and when built in 2012 had 100A service supplying lights, GDO, outlets, and a septic lift pump and alarm for sink and eventual bath. Service is off the main panel for the house that sits outside at the meter and goes through conduit to the detached over a 100A breaker.

I just finished roughing in the room upstairs and am getting ready for inspection. The panel doesn't currently seem to have its own earth ground, does it need one? Anything else look amiss? I basically added about 70% of the circuits to what was already installed and cleaned things up a bit.




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[Norcal]

If ground rods are used, then 2 are required, driven at least 6 feet apart, also the panel shown, if in a detached structure requires a main.

 

[matt_i]

Whats up with the curly neutrals?

 

[MushCreek]

I put in ground rods for my barn (120' away), and the inspector told me I didn't need them. I guess they don't do any harm. I would always ask your inspector to be sure.

 

[pgray007]

Whats up with the curly neutrals?

For whatever reason, Square D GFCI, AFCI, and combo breakers have those wacky curled neutral pigtails built into the breaker.

With the upstairs being a living space, I needed a lot of AFCI.


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[pgray007]

For whatever reason, Square D GFCI, AFCI, and combo breakers have those wacky curled neutral pigtails built into the breaker.

With the upstairs being a living space, I needed a lot of AFCI.

I don't know if there's some design intent to the curls.


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[Bottlecapdigger]

Not sure about your codes there, but does it not need a disconnect for a panel in a detached building? BCD.

 

[acer66]

Not sure about your codes there, but does it not need a disconnect for a panel in a detached building? BCD.

It needs a disconnect when you have more then 6 breaker here in the US.

 

[tyme2par4]

Whats up with the curly neutrals?

Those are GFCI or AFCI breakers. The neutral and hot both get attached to the breaker, and then the breaker has it's own neutral pig tail.
The new square D load centers have breakers that clip onto the neutral rail to eliminate the pig tail.

 

[Aceman]

Like the others said, you have more than 6 breakers in your panel, so you need a main breaker.

 

[kd7gab]

From some of my reading here, it seems I might need a separate growing rod in my detached garage.

The detached sits about 8-10 feet from the main house, and when built in 2012 had 100A service supplying lights, GDO, outlets, and a septic lift pump and alarm for sink and eventual bath. Service is off the main panel for the house that sits outside at the meter and goes through conduit to the detached over a 100A breaker.

I just finished roughing in the room upstairs and am getting ready for inspection. The panel doesn't currently seem to have its own earth ground, does it need one? Anything else look amiss? I basically added about 70% of the circuits to what was already installed and cleaned things up a bit.




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You will need to remove any bonding strap from the nuetral buss in your subpanel. The ground and nuetral are only bonding at the first panel, the first fed from the service entrance (current code). This is generally a super easy item to address and something an inspector should look for.

 

[pgray007]

You will need to remove any bonding strap from the nuetral buss in your subpanel. The ground and nuetral are only bonding at the first panel, the first fed from the service entrance (current code). This is generally a super easy item to address and something an inspector should look for.

There's a separate grounding strip (hard to see in the pic, top left) that doesn't seem to be connected to the panel in any way. How would I know if there's a bonding strap? A "real" electrician installed the panel when the house was built in 2012, but based on my reading here that doesn't necessarily mean everything is done as well as it could be.

 

[LMS]

My electrician didn't put one in for my detached shop, but the inspector said I needed one, so I put it in

 

[pgray007]

Like the others said, you have more than 6 breakers in your panel, so you need a main breaker.

That would make sense, since there were fewer than 5 or 6 breakers when the panel was originally installed and inspected.

Is this as simple as putting a 100A breaker in the spot at the bottom, or is there something special about a "main breaker."

I've tried googling this but am probably using the wrong terminology... Just want to make sure I get the right thing at Big Blue.

 

[wyliesdiesels]

I put in ground rods for my barn (120' away), and the inspector told me I didn't need them. I guess they don't do any harm. I would always ask your inspector to be sure.

Inspectorwas wrong.

Grounding electrodes main purpose is to ground lightning strikes.

There's a separate grounding strip (hard to see in the pic, top left) that doesn't seem to be connected to the panel in any way. How would I know if there's a bonding strap? A "real" electrician installed the panel when the house was built in 2012, but based on my reading here that doesn't necessarily mean everything is done as well as it could be.

That ground bar IS connected to the panel via the screws. Its also tied to the main via the wire on the left thats part of the feeder.

As far as bonding of the neutral u need to make sure that there are no screws, (suppose to be green) that are screwed into any of the neutral bars.

And heres an article about the difference between EGCs and grounding electrodes to help further understandthe need for rods:

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

That would make sense, since there were fewer than 5 or 6 breakers when the panel was originally installed and inspected.

Is this as simple as putting a 100A breaker in the spot at the bottom, or is there something special about a "main breaker."

I've tried googling this but am probably using the wrong terminology... Just want to make sure I get the right thing at Big Blue.

Im not totally familiar with that panel but it looks like its a convertable main lug where u couldput in a main breaker. U need to find a square D catalog and lookup the panel model
Number then look for the main breaker part no for that panel. Or go to a local electrical supplier and they should be able to help u.

 

[L Henry]

Is that Aluminum wire on the feeders . Haven't used in decades.

 

[ddawg16]

As Wylie said....yes, you need a main disconnect...I would do as he suggested regarding the options for the panel.

Yup....need ground rods. 2 Of them...at least 6' apart with at least a #8 copper wire...bare is fine. If you use the right clamp, you can bury the whole mess after inspection.

On detached buildings, the earth ground does NOT connect to the neutral. You tie the neutral to ground at one place only, your main panel. The earth ground from your main feed should also tie to the earth ground in your panel.

Looking at the panel, it looks like it's installed up-side down. Not a big deal....I personally prefer the main breaker at the top.

That panel could use a little clean up. It's ok to dress those neutrals for the AFCI's and GFCI's.

 

[wyliesdiesels]

Is that Aluminum wire on the feeders . Haven't used in decades.

What are u implying? That he shoulsnt use al wire?

As Wylie said....yes, you need a main disconnect...I would do as he suggested regarding the options for the panel.

Yup....need ground rods. 2 Of them...at least 6' apart with at least a #8 copper wire...bare is fine. If you use the right clamp, you can bury the whole mess after inspection.

On detached buildings, the earth ground does NOT connect to the neutral. You tie the neutral to ground at one place only, your main panel. The earth ground from your main feed should also tie to the earth ground in your panel.

Looking at the panel, it looks like it's installed up-side down. Not a big deal....I personally prefer the main breaker at the top.

That panel could use a little clean up. It's ok to dress those neutrals for the AFCI's and GFCI's.

#8 needs to be in conduit, #6 can be bare without conduit as long as its not subject to damage..

 

[Norcal]

What are u implying? That he shoulsnt use al wire?
..

Sounds like another scare monger.

 

[NUTTSGT]

Sounds like another scare monger.

Or confusing it with Aluminum Romex/NM.

 

[pgray007]

This is incredibly helpful advice. To summarize my "cleanup" activities and ask a few questions:

1) Main breaker makes perfect sense. I'll get the appropriate part from the Square D catalog.

2) Upside-down box "came that way" with the house. Not sure why it was upside down -- perhaps the sparky was Australian? It does work out OK since the door to the breaker box opens opposite the low voltage can, and the box does seem to "go both ways" since all internal markings are written in both directions.

3) Neutral bonding - I didn't see any green screws and don't see any connections between the neutral bar and box, so I assume I'm OK here.

4) There does seem to be some grease or glue on the two mains coming into the subpanel. Is this dielectric grease or similar? Anything I need to apply when moving the mains to accommodate the shutoff?

5) Cleanup - I'll uncurl the neutrals on those breakers. They look messy but I assumed the served some function as they weren't uncurled in the other panels, but the only "purpose" I can discern is perhaps to save space in the packaging.

6) Grounding - The need for grounding makes sense to me. Ideally I'd like to avoid going to the exterior with the grounding wire right by the panel purely for aesthetic reasons, since that would mean I'd have a grounding wire running in a high visibility area. Here's what I mean (smaller conduit is LV going to the white LV can pictured above):



So now for some dumb grounding questions:

Is the primary focus of grounding the detached panel to prevent lightening or a major overcurrent fault from exiting through the conduit back to the main panel, and doing bad things to the conduit along the way?

Can I take the grounding wire through the studs, and pop it out just past the edge of the patio in the picture, so I can drop down to ground level with minimal exposed wire? If so:

- Anything special I need to do running the ground wire inside/outside the house, or just go through studs and use nail plates like it's romex? Do I need any special staples/supports along the way?

Anything special I need to do to seal the penetration, or do I just drill a hole, stick the wire through, and whack it with some spray foam?

Any tricks to driving the grounding rod, other than walk softly and carry a big sledge? We have mostly clay so maybe I'll wait for a good rain to pass by.

Finally, with the 6' away second grounding rod, the cumulative distance will be a bit more than the distance from the detached panel to the main panel on the house, does that matter? Won't electricity always follow the shorter path limiting the usefulness of the second rod?

Thanks again, this has been very helpful and informative!!!

 

[pgray007]

Is that Aluminum wire on the feeders . Haven't used in decades.

The electrician who wired the house did the panel and the interconnect, so I have no idea the logic behind his wiring choice, although it did pass the initial inspection when the house/detached were built in 2012.

 

[Norcal]

The panel is not " upside down" it can be used either way, anyone who says otherwise does not know what they are talking about, older panels which had main breakers with off and on in a vertical position were not allowed to be flipped because on would then be in the down position. That SQ D panel may accept a main breaker kit otherwise a holddown kit will be required to be installed on a backfed main.

 

[wyliesdiesels]

Sounds like another scare monger.

Exactly my thoughts but wasnt gonna take it that far.

This is incredibly helpful advice. To summarize my "cleanup" activities and ask a few questions:

1) Main breaker makes perfect sense. I'll get the appropriate part from the Square D catalog.

2) Upside-down box "came that way" with the house. Not sure why it was upside down -- perhaps the sparky was Australian? It does work out OK since the door to the breaker box opens opposite the low voltage can, and the box does seem to "go both ways" since all internal markings are written in both directions.

3) Neutral bonding - I didn't see any green screws and don't see any connections between the neutral bar and box, so I assume I'm OK here.

4) There does seem to be some grease or glue on the two mains coming into the subpanel. Is this dielectric grease or similar? Anything I need to apply when moving the mains to accommodate the shutoff?

5) Cleanup - I'll uncurl the neutrals on those breakers. They look messy but I assumed the served some function as they weren't uncurled in the other panels, but the only "purpose" I can discern is perhaps to save space in the packaging.

6) Grounding - The need for grounding makes sense to me. Ideally I'd like to avoid going to the exterior with the grounding wire right by the panel purely for aesthetic reasons, since that would mean I'd have a grounding wire running in a high visibility area. Here's what I mean (smaller conduit is LV going to the white LV can pictured above):

So now for some dumb grounding questions:

Is the primary focus of grounding the detached panel to prevent lightening or a major overcurrent fault from exiting through the conduit back to the main panel, and doing bad things to the conduit along the way?

Can I take the grounding wire through the studs, and pop it out just past the edge of the patio in the picture, so I can drop down to ground level with minimal exposed wire? If so:

- Anything special I need to do running the ground wire inside/outside the house, or just go through studs and use nail plates like it's romex? Do I need any special staples/supports along the way?

Anything special I need to do to seal the penetration, or do I just drill a hole, stick the wire through, and whack it with some spray foam?

Any tricks to driving the grounding rod, other than walk softly and carry a big sledge? We have mostly clay so maybe I'll wait for a good rain to pass by.

Finally, with the 6' away second grounding rod, the cumulative distance will be a bit more than the distance from the detached panel to the main panel on the house, does that matter? Won't electricity always follow the shorter path limiting the usefulness of the second rod?

Thanks again, this has been very helpful and informative!!!

Answering in order of bolded text above:

*The greasy substance is no-alox or similar brand. Its to prevent corrosion on the al wire. It maybor may not be required by the manufacturer of the wire but seeing as we dont know what brand the wire is and the original electrician used it, u should use it when u install the main breaker.

Contrary to popular misbelief, al corrosion inhibitor is ONLY REQUIRED by code IF the manufacturer requires it.

*yes u can bring the ground wire out in a better location past the concrete.

*keep in mind theres 2 types of grounding and u answered your own question in regards to the need for both. Weve discussed the rods and the EGC between the main and sub provides a low impedance path for fault current so the feeding breaker can trip if theres a ground fault on the feeder. It is necessary because the neutral isnt bonded, as it shouldnt be. If the neutral was bonded it would provide the fault current path. Neutrals cannot be bonded in subpanels starting with 2008 NEC code cycle and for good reason. A bonded neutral can create a dangerous situation IF the neutral looses connection to the upstream panel.

*yes the GEC-grounding electrode conductor as its called, can go through the studs. No special handling needed other than making sure its not subject to damage

I would use silicone as foam turns nasty with the sun

I would use a t post pounder. Sledges tend to dlip and make it hard to drive the rod. If u have a hammer drill, certain brands have attachments for driving rods.

As far as distance between rods, u only have to drive a second rod because u cant prove that u have 25ohms or less of resistance to earth. U may very well be good with one but assuming u dont have the expensive meter to test with, code requires 2 rods.

Also, electricity from your electrical service wont flow on these rods theyre only for lightning which will take numerous different paths to earth...

 

[sberry]

It is necessary because the neutral isnt bonded, as it shouldnt be. If the neutral was bonded it would provide the fault current path. Neutrals cannot be bonded in subpanels starting with 2008 NEC code cycle and for good reason. A bonded neutral can create a dangerous situation IF the neutral looses connection to the upstream panel.

To add to this,,, the idea of a separate neutral is to be able to insulate neutral and eliminate alternate current pathways. All the operating currents are being carried on insulated wires.

 

[wyliesdiesels]

Thx sberry.

Forgot to add the part about alternate pathways.

 

[pgray007]

Thanks for all the advice, all. I'm now grounded, can confirm that neutral is not bonded, and have a main disconnect. Thanks for the great advice! I also did some minor panel cleanup, although didn't have the patience to pull all the breakers and fully untwist the neutrals.



Right bicep now much stronger:


Finished product:

 

[-Brent-]

I just put in ground rods and was told to run #8 ground for 100A service. What size do you have there and can anyone give the theory on ground wire sizing. I'd like to know.

 

[acer66]

I just put in ground rods and was told to run #8 ground for 100A service. What size do you have there and can anyone give the theory on ground wire sizing. I'd like to know.

Solid #6 is better. It can be run unprotected. #8 must be protected where ever it is exposed. Ground cannot be interrupted, must be one continuous wire. Only way to join wires is using approved permanent connection methods such as exothermic welding.

Charles

http://www.garagejournal.com/forum/showpost.php?p=2577966&postcount=2

 

[-Brent-]

http://www.garagejournal.com/forum/showpost.php?p=2577966&postcount=2

I read that but I was wondering the theory behind it. I'm working to increase my knowledge on this stuff. I'm learning, slowly.

Edit: My #8 is sheathed.

 

[wyliesdiesels]

It has to do with impedance of the wire per ft.

As has been said #6 is easier because it doesnt HAVE to be in conduit UNLESS subject to damage.

 

[pgray007]

It has to do with impedance of the wire per ft.

As has been said #6 is easier because it doesnt HAVE to be in conduit UNLESS subject to damage.

I used #6 specifically so I wouldn't have to deal with conduit.


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[pgray007]

Thanks for your guidance everyone. I passed my electrical with flying colors!


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