Help on grounding this setup/mast.

[JoshuaHufford]

Just had a new roof put on my house, while they had the shingles off I installed a 1.5" rigid conduit through the sheeting and secured it to the rafters, then the roofers installed a roof jack over the conduit. Thanks to mmckenna for the great idea of doing this.

Now I need to ground it, this is an older house, very few of the electrical outlets have a proper ground, and getting a ground wire from the attic to my ground rod would not be easy. My electrical weather head is not too far away on the same side of the roof, could I run a ground wire to that? I know that is bonded to my ground rod. Or does it need to have it's own ground wire going directly to my ground rod?

Other problem is my ground rod appears to have been covered over with concrete at some point before we bought the house. There is a ground wire that runs in conduit down into the concrete directly under my meter box so I'm guessing that is where the ground rod is, and if I put my meter on a hot wire and the other lead on that wire I do get 120v so it has to be some kind of ground connection. Because of this I was thinking of adding a second ground rod, but I can't bond them directly together without busting up concrete. So if I added a second ground rod can I bond them together to main conduit that connects the weather head to my meter box?

Thanks for any input you have.

 

[mmckenna]

Just had a new roof put on my house, while they had the shingles off I installed a 1.5" rigid conduit through the sheeting and secured it to the rafters, then the roofers installed a roof jack over the conduit. Thanks to mmckenna for the great idea of doing this.

Glad it worked for you. We've done it on a few commercial installs where we had access before the roof was installed, or during retrofit. Saves some headaches if it's done right.

Now I need to ground it, this is an older house, very few of the electrical outlets have a proper ground, and getting a ground wire from the attic to my ground rod would not be easy. My electrical weather head is not too far away on the same side of the roof, could I run a ground wire to that? I know that is bonded to my ground rod. Or does it need to have it's own ground wire going directly to my ground rod?

Just for safety grounding, bonding to the conduit for the weather head would work. For lightning protection, you want as straight and uninterrupted path to a ground rod as possible. Your goal should be both lightning protection and safety. A ground rod below the antenna mount would be ideal, and have that bonded to the house ground would solve the NEC concerns.

A competent electrician with grounding system experience could advise better than this random dude on the internet can. But reading the NEC section on grounding would be a good idea.

Other problem is my ground rod appears to have been covered over with concrete at some point before we bought the house. There is a ground wire that runs in conduit down into the concrete directly under my meter box so I'm guessing that is where the ground rod is, and if I put my meter on a hot wire and the other lead on that wire I do get 120v so it has to be some kind of ground connection. Because of this I was thinking of adding a second ground rod, but I can't bond them directly together without busting up concrete. So if I added a second ground rod can I bond them together to main conduit that connects the weather head to my meter box?

In most electrical systems, the neutral is bonded to ground. So getting a circuit through what may or may not be a ground rod doesn't mean you have a good ground. It just means that some electrician did his/her job and bonded neutral to ground in the panel, like they are supposed to.

Ground rod may or may not be there. Could be that the rebar under the concrete is being used as part of the ground system. In homes with concrete foundations or built on concrete slabs, it's not uncommon to see a piece of rebar sticking up and the ground wire connected to that.

If you are unsure of your ground, contact and electrician. They may have a ground resistance meter and could confirm your ground is good or not. Usually for commercial communications use, you want your ground to be 5Ω or less. They'd need the right sort of tester, and they'd need to disconnect the ground in your panel, which creates a safety hazard, so usually the main breaker is opened when this is done.

Or, you could just drive in a new rod and bond that to the existing system. PRCGUY swapped out on of his ground rod, he mentioned in in one of his recent posts. He's probably a good resource for this sort of stuff.

 

[JoshuaHufford]

I'll just go ahead and drive a new ground rod since I don't know if I have one or not currently. Do you know if it would be OK to bond the new ground rod to my main conduit coming into the home? I'll probably double check with an electrician as well, just like getting input here as well.

 

[mmckenna]

I'll just go ahead and drive a new ground rod since I don't know if I have one or not currently. Do you know if it would be OK to bond the new ground rod to my main conduit coming into the home? I'll probably double check with an electrician as well, just like getting input here as well.

You -can- bond it to the conduit, but you also will need to connect it directly to the ground buss in the panel.