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Sub Panel Ground Question

wyliesdiesels

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rockcrawler

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mike93lx

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Yeah, I found their website yesterday. Thanks. I just can’t see enough of the jacket to see the writing on it to determine what it is. I’m not sure how I’ll be able to tell. I may have to disconnect the cable on each end and pull it out on one end enough to read the jacket.
Why are you wondering? The ground is wrapped in paper... It's NM-B and can't be underground or outdoors, at all
 
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rockcrawler

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Finding out now is a hell of a lot better than when there is a problem. You can get this sorted out. Just keep asking questions before buying stuff

Thanks.

So, it looks like my shopping list consists of:

110’ of #3 THWN (2 blk/1 wht), 110’ of #8 THWN (green), 2 - 1/2” x 8’ ground rods, 2 - 1/2” ground rod clamps, and some #6 solid copper ground wire.

Does this sound about right?
 
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rockcrawler

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So, I have a new question. If I will be grounding the 1st panel in the shop with the two grounding rods, will I still need to run a ground from the main (house) panel when I replace those wires with the proper wiring?
 

dave*99

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So, I have a new question. If I will be grounding the 1st panel in the shop with the two grounding rods, will I still need to run a ground from the main (house) panel when I replace those wires with the proper wiring?
YES The ground wire between the house and shop serves a different function than the ground rods. You need both.
 

wyliesdiesels

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So, I have a new question. If I will be grounding the 1st panel in the shop with the two grounding rods, will I still need to run a ground from the main (house) panel when I replace those wires with the proper wiring?
you should reference the pics in post #3 here

 
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rockcrawler

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you should reference the pics in post #3 here


When looking at the detached building image, it shows to bond the ground bar to the sub panel. Will scraping some paint off the box under the bar and mounting the bar with the two supplied screws be sufficient?
 

wyliesdiesels

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When looking at the detached building image, it shows to bond the ground bar to the sub panel. Will scraping some paint off the box under the bar and mounting the bar with the two supplied screws be sufficient?
you dont need to scrape off paint. the 2 screws and threads should be sufficient as they are listed for that install
 
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rockcrawler

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Update:

I finally got the chance to get the two 5/8” x 8’ grounding rods installed today. They are buried 6’ apart and about 6” or so underground. I have a #6 solid ground wire running between the two and run through the slab and into the panel. I also got the separate ground bar mounted in the panel and moved all the grounds over to it. Now the grounds and neutrals are separated as they should be.

I have also received the x3 #1 aluminum power wire and x1 #6 copper ground wire so that I can replace the Romex that was used from the house to the shop by the original “electrician”. That will be done later.


IMG_3616.jpeg

IMG_3617.jpegIMG_3618.jpegIMG_3619.jpeg
 
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luvtheheat

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The ground wire between the house and shop serves a different function than the ground rods. You need both.
What are the different functions of the two grounds? If all the grounds are ultimately bonded together ( as in post #3 pictures in the sticky thread referenced earlier), what are the different purposes?

Not arguing, just want to learn.
 

mike93lx

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What are the different functions of the two grounds? If all the grounds are ultimately bonded together ( as in post #3 pictures in the sticky thread referenced earlier), what are the different purposes?

Not arguing, just want to learn.
Code requirement to ensure proper grounding. Other option is a single rod but it requires proving a certain resistance level, and that necessitates expensive equipment.
 

dave*99

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Code requirement to ensure proper grounding. Other option is a single rod but it requires proving a certain resistance level, and that necessitates expensive equipment.
I suspect he is asking about the difference between the ground conductor running from the house to the garage compared to the pair of ground rods. I think that is what he means by two grounds.

I'll wait for his reply before typing that explanation out, or you may want to if you have the time.
 

wyliesdiesels

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What are the different functions of the two grounds? If all the grounds are ultimately bonded together ( as in post #3 pictures in the sticky thread referenced earlier), what are the different purposes?

Not arguing, just want to learn.
are you referring to the EGC running between the panels and the grounding electrodes?

if so its explained in the electrical FAQs sticky post #4

 

luvtheheat

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I suspect he is asking about the difference between the ground conductor running from the house to the garage compared to the pair of ground rods. I think that is what he means by two grounds.

I'll wait for his reply before typing that explanation out, or you may want to if you have the time.
OK, I read sticky post #4, question answered.

Thanks all.
 

Innovate1

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So I need 2 black (hot) #2 THWN, 1 white (neutral) #4 THWN and 1 green (ground) #6 THWN? My house main panel has a 100 amp breaker feeding the shop panel. The shop panel has a 100 amp breaker in it and I have a 100 amp breaker that will feed the 2nd sub panel in the shop. Are you saying I need to buy three 90 amp breakers? One for the main panel to feed the shop panel, one for the incoming power in the 1st shop panel and one feeding the second shop panel? My second shop panel is lug only.
Having a 100A breaker feed the second panel in the shop is ok but likely overkill. Unless there is a need to put big loads on the second panel it seems like 50 or 60A would be sufficient. You might even be able to use some of the current feed line from the house.
 
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Norcal

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looks like you have a GE panel so that Eaton 100a breaker should not be in there. needs to be replaced with a GE breaker
A Eaton CL would be OK, but a GE is the ideal solution, I really don't like classified breakers unless have to use them.
 

sparky 1971

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A Eaton CL would be OK, but a GE is the ideal solution, I really don't like classified breakers unless have to use them.
While I agree 100%, I've always wondered what difference between the BR and CL breakers is other than packaging and price.
 

Norcal

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While I agree 100%, I've always wondered what difference between the BR and CL breakers is other than packaging and price.
They chose not to have the Zinsco II classified, seems like it would be cheaper to have the BR classified then manufacture & stock two different product lines, but must be a marketing & bean counter decision.
 

sparky 1971

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It's just a hunch, but I bet they are the same thing. Someone decided they could make a little more money putting them in a different package and selling them as Siemens and GE compatible. If they charged the same amount for BR breakers it would cut into the sales of the panels and nobody would use them. I don't use anything BR unless a place already has a BR panel, but from what I remember, it seems BR is the cheapest line the box stores carry.
 

justsam

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Regarding the main house panel breaker feeding the shop sub panel, I should have been more clear if you had a picture with the dead front off the main panel. Just want to confirm that there is no transition from one cable type to another somewhere along the route. Please only do this if you are comfortable removing the dead front.

Also, in the picture of the sub panel what is the armored cable off to the bottom right? At the time of shop construction was the electrician ever talking about a ufer ground or did you see any wiring to rebar?
 
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rockcrawler

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Regarding the main house panel breaker feeding the shop sub panel, I should have been more clear if you had a picture with the dead front off the main panel. Just want to confirm that there is no transition from one cable type to another somewhere along the route. Please only do this if you are comfortable removing the dead front.

Also, in the picture of the sub panel what is the armored cable off to the bottom right? At the time of shop construction was the electrician ever talking about a ufer ground or did you see any wiring to rebar?

I‘ll get an inside pic in a couple of days when I get a chance. Are you talking about the MC cable running behind the panel in the first pic? All of the electrical in the shop was wired with MC. I don’t remember the electrician saying anything about a ufer ground. All of the electrical was done after the shop was completed and just before spray foam, so there wasn’t any wiring to rebar that I know of.
 
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rockcrawler

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looks like you have a GE panel so that Eaton 100a breaker should not be in there. needs to be replaced with a GE breaker

Absolutely nothing surprises me when it comes to the electrical work that was done on my shop. I just found out the other day that the motion flood light that was installed over the back door has no junction box. The wires just come into the shop and were joined with the MC with wire nuts and covered with spray foam. I found it buried in the spray foam when I ran the EMT for my second shop panel.



IMG_3631.jpeg
 
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sparky 1971

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I‘ll get an inside pic in a couple of days when I get a chance. Are you talking about the MC cable running behind the panel in the first pic? All of the electrical in the shop was wired with MC. I don’t remember the electrician saying anything about a ufer ground. All of the electrical was done after the shop was completed and just before spray foam, so there wasn’t any wiring to rebar that I know of.
If a UFER was installed, it wasn't connected to. There would be a ground wire running to it and there is nothing that matches that description in the panel. The ground rods take its place.
 
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rockcrawler

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Pic of my new sub panel in the back of the shop. It’s not currently connected to the panel at the front.



IMG_3633.jpeg
 
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rockcrawler

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It is not code compliant to use white phase tape on a conductor smaller then 4 AWG, it must have white colored insulation.

That is 4 awg. But, I guess that means I have to remove the red tape from the white wire going into the breakers for my mini splits. I thought I was supposed to mark that red or black somehow so I just used phase tape.

IMG_3635.jpeg
 
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Norcal

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That is 4 awg. But, I guess that means I have to remove the red tape from the white wire going into the breakers for my mini splits. I thought I was supposed to mark that red or black somehow so I just used phase tape.

IMG_3635.jpeg
That is fine, the grounded (neutral) needs to have white or gray colored insulation, and a grounding conductor needs green colored insulation if it smaller then 4 AWG, what was done to reidentify the white on those 240V circuits is just fine, and no need to change it & explains the 25A breakers.
 

justsam

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I may be getting fooled by the close up photos but that looks too small for4ga, and too large for 14ga. How large or how far away are these mini splits that they need to be fed with 4 ga wire?
 
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