Grounding rod needed? Detached garage from sub panel

[infinkc]

Property I have had a garage in the back that has 10ga running from a sub panel in the main building via metal conduit 2 hot and a neutral.

There was a old fuse box disconnect there before.

I want to replace it with another sub panel and breakers.

I noticed there is no grounding rod on the garage. should there be one or two? or is how they ran it ok still?

 

[Terry D]

Is it metal conduit just stubbed up out of the ground or continuous conduit the whole way. With an old 3-wire service to a detached garage, there cant be any metallic pathways between the 2 buildings. Regardless, there should be 2 ground rods out at the garage. Guess I should have asked first, is this a detached garage?

Post some pictures of what you have

 

[ddawg16]

Per code for detached buildings.....2 ground rods....unless you can prove there is less than 25 ohms to earth ground with one rod.

I think it's 25 ohms,'

It's just easier to slam 2 rods in about 8-10 ft apart and call it a day..

And they can be below ground....but confirm for your area just in case

 

[wyliesdiesels]

Yes ground rods are required

Check the diagrams in the electrical FAQ sticky

Also, that 3-wire may need to be upgraded

 

[infinkc]

Is it metal conduit just stubbed up out of the ground or continuous conduit the whole way. With an old 3-wire service to a detached garage, there cant be any metallic pathways between the 2 buildings. Regardless, there should be 2 ground rods out at the garage. Guess I should have asked first, is this a detached garage?

Post some pictures of what you have

Sorry don’t have any pictures, I tore the building down and putting a new one up. I am not sure if the conduit is going all the way to the other building. Its about 80 feet away.
I will ohm out the neutral to the conduit and see if there is any reading.

will need to pick some rods up, I ordered the sds hammer tool to make life easier. Just wanted to take care of the grounding as I need to pour concrete around the new building and now would be the time.

didn’t seem right to me that it originally had no separate ground for the building. But it was probably put up in the 70s.

 

[nadogail]

If you are going to pour concrete, find out if a UFER ground is acceptable. My home built in 1988 has a UFER ground, for the main panel, when my service was changed from 100 Amps to 200 Amps and Solar panels were added, the sub panel and Solar installation was grounded with 2 rods.

Your local requirements may be different, I suggest you contact your local permitting authority.

 

[Terry D]

No trying to spend your money, but if the building is getting replaced, It is a code requirement to replace that old 3-wire feed with a 4-wire ( 2 hots, 1 neutral and a equipment ground) Plus it would give you the opportunity to up the size of the feed, don't know what you plan on putting out there, but 30 amps isn't all that much

 

[jmdirk]

Depends on location. There's a bit of a discussion in another thread as this is where the NEC and CEC (Canadian Electrical Code) differ. If you're in Canada if you're tying a sub-panel to the main panel, you bond the sub-panel to the main. Only one ground rod.

 

[wyliesdiesels]

yeah OP where are you located?