Running a ground........

[jwillis]

I have put a metal garage out in the middle of my back yard on a concrete slab that was already there. The electric was run underground from my house out to a light pole next to where the garage now sits. Since my house was built in the fifties, the wire that was run out there, (which was also put there in the late fifties) is 12/2 with no ground. Just like my house. When I built my garage this spring, I just attached the electric in my new garage to the wire that was already there. But now I have three prong out lets with a ground. I am considering running a new line out from the house directly from the breaker box in the basement and putting the garage on it's own separate circuit. Should I tap into the ground wire that is now going around inside the garage to the outlets and run it down into a grounding rod (electrode) outside the garage? Thanks for any help.........jwillis

 

[sdowney717]

IF you use GFCI breaker then the ground is not needed and you can keep using your same wire.

 

[kbs2244]

Or, if your code will allow it, just pound in a ground rod at the garage.

 

[mrb]

Or, if your code will allow it, just pound in a ground rod at the garage.

a ground rod does not create a return path for fault current and will do nothing to make this situation safer. even with your ground rod, if something shorts out the entire metal building could become energized and kill someone. the grounding wire back to the service provides a return path for fault current so a protective device will trip.

The wire should really be replaced, but at a mimimum it should be supplied with a GFCI. Not gfci receptacles, but the circuit going out there should be protected by a GFCI.

 

[jwillis]

The wire going out to the garage has a breaker at the main breaker box, now. (There is no breaker box in the garage). If I run a completely new wire out from the main house breaker box (say a 14/2 with a ground) it will be tied into a breaker at the breaker box, also. So, this should be ok? (I just thought a grounding rod at the garage would give me added protection if I connected it to the grounding wire that is going around through all the recepticles.)

 

[mrb]

The wire going out to the garage has a breaker at the main breaker box, now. (There is no breaker box in the garage). If I run a completely new wire out from the main house breaker box (say a 14/2 with a ground) it will be tied into a breaker at the breaker box, also. So, this should be ok? (I just thought a grounding rod at the garage would give me added protection if I connected it to the grounding wire that is going around through all the recepticles.)

if you have one circuit going to the garage you dont need a ground rod. if you install a subpanel at the garage you do need a ground rod (two actually).

if you have a ground rod at the garage with no ground wire back to the panel supplying it, that is not a safe installation.

youre only allowed one circuit to a detached building (a multiwire branch circuit ie: 12/3 fed from 2 pole breaker) is considered one circuit. You cant have two seperate runs.

If you are going to the trouble of running a new line out there, consider at least running 12/3 then you have two 20 amp circuits.

 

[frank_c]

i'm kind of in the same boat as the OP, no grounds in the garage. so far it's not a problem, but i'm planning for the future.

youre only allowed one circuit to a detached building (a multiwire branch circuit ie: 12/3 fed from 2 pole breaker) is considered one circuit. You cant have two seperate runs.

two separate energized runs? is it legal to "abandon" one run (as in disconnect from the main panel and disconnect from the garage) and run a different (grounded and properly protected) line to a new subpanel?

 

[jwillis]

if you have one circuit going to the garage you dont need a ground rod. if you install a subpanel at the garage you do need a ground rod (two actually).

if you have a ground rod at the garage with no ground wire back to the panel supplying it, that is not a safe installation.

youre only allowed one circuit to a detached building (a multiwire branch circuit ie: 12/3 fed from 2 pole breaker) is considered one circuit. You cant have two seperate runs.

If you are going to the trouble of running a new line out there, consider at least running 12/3 then you have two 20 amp circuits.

What I had planned was that once I ran a new circuit out to the garage from the breaker box in the house, then I would disconnect it at the other end. I know there should not be a loop in the electric. The reason I think it needs to be replaced is because, as I said earlier, the old wire was only run out to a light pole in the middle of the yard to a light pole in the late 1950s alongside a basketball court. Now, I have placed my garage on that concrete slab that used to be a basketball court and ran the electrical cord about 15 feet over to my new garage. The concern is that a 30 foot tree is now right over the old underground wire so I thought I should run a new wire out from the house and then disconnect the old one. It will be a 14/2 or 12/2 with a ground. But it will be connected to the breaker box and have a breaker on it. If I don't have any heavy equipment, do you think 14/2 with a ground will be big enough? That is all that is out there now and it seems to run everything OK.

 

[Norcal]

14 AWG is a waste of money as a feed to a building, run conduit & oversize it it's cheap insurance to upgrade in the future if needed or desired.

 

[sdowney717]

new wire to a garage you should spend some money and go much bigger to get some amps out there. Someone might want to run lights and a saw or 2
Consider a 10 gauge with GFCI breaker in the box.
plastic conduit is so cheap, go big enough to pull other things later and leave pull strings inside.

 

[avc8130]

Run 2 conduits. That way you can run power now, and if you ever want ethernet or coax you can do it later in the other conduit.

If you run a subpanel, you should isolate the ground in the subpanel and run the ground back to the main panel in the house.
ac

 

[6768rogues]

What you don't want to do is to connect your building to the house ground electrode AND a ground rod at the garage. The earth has different grounding potentials in different locations, and two ground rods remote from each other and connected together can turn the ground conductor into a current carrying conductor from one ground potential to the other. Either ground back to the house ground OR ground separately with rods at the garage.

 

[mrb]

What you don't want to do is to connect your building to the house ground electrode AND a ground rod at the garage. The earth has different grounding potentials in different locations, and two ground rods remote from each other and connected together can turn the ground conductor into a current carrying conductor from one ground potential to the other. Either ground back to the house ground OR ground separately with rods at the garage.

that is entirely incorrect and DANGEROUS.

you are REQUIRED* to have a grounding electrode (ground rod) at the detached building, and REQUIRED to have a EGC (equipment grounding conductor -'ground wire') from the panel at the detached structure back to the supply. This ground wire has to be in the same conduit or cable as the other circuit conductors.

* if you have only one circuit to the detached structure, a grounding electrode is not required at the detached structure but the EGC (ground wire) is still a must.

 

[Joe92GT]

that is entirely incorrect and DANGEROUS.

you are REQUIRED* to have a grounding electrode (ground rod) at the detached building, and REQUIRED to have a EGC (equipment grounding conductor -'ground wire') from the panel at the detached structure back to the supply. This ground wire has to be in the same conduit or cable as the other circuit conductors.

* if you have only one circuit to the detached structure, a grounding electrode is not required at the detached structure but the EGC (ground wire) is still a must.

You have to have a ground rod on a detached building? I thought there should be only one point of ground for a service, and only at that point should the neutral and ground be connected.

A ground rod at the garage could create weird situations current from a fault in the garage right?

Either way, for the OP I would never consider running a non-grounded circuit to a garage. Everything you'll be using will most likely be a power tool and in your hands. If for some reason there is a fault in a tool, you can become the only path for that fault back to ground, and that is bad.

Since the main cost of running wire to the garage is labor, I'd run at least a 6-3 wire on a 50A breaker. Then install a small sub panel in the garage, and wire off of that.

 

[mrb]

You have to have a ground rod on a detached building? I thought there should be only one point of ground for a service, and only at that point should the neutral and ground be connected.

A ground rod at the garage could create weird situations current from a fault in the garage right?

Either way, for the OP I would never consider running a non-grounded circuit to a garage. Everything you'll be using will most likely be a power tool and in your hands. If for some reason there is a fault in a tool, you can become the only path for that fault back to ground, and that is bad.

Since the main cost of running wire to the garage is labor, I'd run at least a 6-3 wire on a 50A breaker. Then install a small sub panel in the garage, and wire off of that.

the 'one point of ground' you are thinking of is the connection between neutral and ground. this is called the main bonding jumper and must only occur once at the service. every detached structure requires a grounding electrode unless supplied by only one circuit (i believe 20 amps or less )

again. you cant have just a ground rod, or just a ground wire back to the house. you must have both. all runs to a subpanel need 4 wires.

 

[jwillis]

So, if I only run one grounded wire out to the building and I don't put in a breaker box at this building, I won't have to put in a grounding rod at the building? And if I do run a grounded wire out to the building and I do put in a breaker box, then the breaker box has to be grounded, correct? I can't see myself running any equipment more than a drill or maybe a table or chop saw at the building because I have another shop attached to the house that I use for woodworking and such. The detached garage in my back yard will only be used for keeping my cars and should not have more than floodlights, TV, VCR, stereo inside.

 

[jwillis]

One other question: If I run the wire underground, how deep should I run the wire if I put it in plastic conduit?

 

[Norcal]

One other question: If I run the wire underground, how deep should I run the wire if I put it in plastic conduit?

18" of cover min,24" if subject to vehiculer traffic.

 

[mrb]

So, if I only run one grounded wire out to the building and I don't put in a breaker box at this building, I won't have to put in a grounding rod at the building? And if I do run a grounded wire out to the building and I do put in a breaker box, then the breaker box has to be grounded, correct? I can't see myself running any equipment more than a drill or maybe a table or chop saw at the building because I have another shop attached to the house that I use for woodworking and such. The detached garage in my back yard will only be used for keeping my cars and should not have more than floodlights, TV, VCR, stereo inside.

if you run say a 12/2 (with ground) UF cable out there, you dont need to put a ground rod in. If you install a breaker box, you need to install ground rod (two actually, 6 feet apart) but you still need the ground wire back to the house as well. In the subpanel you need seperate neutral and ground bars and the neutral bar cant be connected to the box or to ground.

 

[sdowney717]

In my city 2 rods 7 feet apart.

If I was doing this on my own hose. I would likely only bury that conduit about 6 to 8 inches deep. I know this is not kosher, but I dont like digging very much.

People I know who have run UF wire outside tend to put it barely under the ground (or not even in some spots). I know because I have seen them doing it. I tell them at least put it in conduit

 

[Norcal]

In my city 2 rods 7 feet apart.

If I was doing this on my own hose. I would likely only bury that conduit about 6 to 8 inches deep. I know this is not kosher, but I dont like digging very much.

People I know who have run UF wire outside tend to put it barely under the ground (or not even in some spots). I know because I have seen them doing it. I tell them at least put it in conduit

Do the job right or don't do it at all, if one dislikes (who does like it?) digging rent a trencher.

 

[jwillis]

Thanks for all the help. I really appreciate it.

 

[avc8130]

if you run say a 12/2 (with ground) UF cable out there, you dont need to put a ground rod in. If you install a breaker box, you need to install ground rod (two actually, 6 feet apart) but you still need the ground wire back to the house as well. In the subpanel you need seperate neutral and ground bars and the neutral bar cant be connected to the box or to ground.

Can you cite the NEC paragraph for this? I am super curious.
ac

 

[mrb]

Can you cite the NEC paragraph for this? I am super curious.
ac

in 2008 its 250.32(A) is where the ground rod(s) are required, and the exception explains that one is not required for a single branch circuit

 

[avc8130]

in 2008 its 250.32(A) is where the ground rod(s) are required, and the exception explains that one is not required for a single branch circuit

Interesting. I have never wired a detached structure, so I have not been that deep into this. Thanks for the reference.
ac

 

[jwillis]

OK. How about I do this........Since my house is only wired for a two wire service with no ground, I run a good, heavy double wire out to my garage and put in a breaker box inside the garage. Then, I can ground the breaker box and attach the ground wire from the 12/2 with a ground that I have running through the recepticles already. Or what if I run the same double wire from the house with no breaker box in the garage and just ground the ground wire that is now running through the recepticles. Would either of these be OK? Thanks.

 

[kbs2244]

If you have a two wire service drop, are we talking a 60 amp service?
If so, you need some serious up grading.

 

[mrb]

OK. How about I do this........Since my house is only wired for a two wire service with no ground, I run a good, heavy double wire out to my garage and put in a breaker box inside the garage. Then, I can ground the breaker box and attach the ground wire from the 12/2 with a ground that I have running through the recepticles already. Or what if I run the same double wire from the house with no breaker box in the garage and just ground the ground wire that is now running through the recepticles. Would either of these be OK? Thanks.

lets get some clarification on what you have going on since your terminology is all over the place. can you post a picture of your service?

 

[jwillis]

If you have a two wire service drop, are we talking a 60 amp service?
If so, you need some serious up grading.

No, it is a 100 amp service. The way the house is wired now, every circuit has one wire (black)to the breaker and the other wire (white)to the ground bar in the breaker box. This is the way they used to wire them. So, I would just like to run two wires out to my garage and make it a three wire system since that is the way my garage is now wired. I would like to run the two wires to the hot side and the grounding wire to the electrode at the garage. This means I would either have to ground the box or ground the ground wire the is now running to my outlets to the grounding electrode. How about that?

 

[Bigpigdave]

Sounds like you are pretty new to electrical work, how about paying an electrician to take a look and give you some recommendations. There seems to be way too many variables for someone on a message board to provide the best solution.
Good luck, Dave

 

[mrb]

No, it is a 100 amp service. The way the house is wired now, every circuit has one wire (black)to the breaker and the other wire (white)to the ground bar in the breaker box. This is the way they used to wire them. So, I would just like to run two wires out to my garage and make it a three wire system since that is the way my garage is now wired. I would like to run the two wires to the hot side and the grounding wire to the electrode at the garage. This means I would either have to ground the box or ground the ground wire the is now running to my outlets to the grounding electrode. How about that?

I too think you should bring in an electrician. No offence, but you do not seem to have enough of a grasp of this to keep from doing something dangerous. Get a licensed electrician over there to take a look.

running the ground wire from your receptacles to a grounding electrode is not going to prevent shock from a ground fault (short) as the protective device is not going to open.

 

[sdowney717]

why not simply put a GFCI breaker on that 12 gauge line in the main box?

 

[mrb]

why not simply put a GFCI breaker on that 12 gauge line in the main box?

why not just ground it properly?