Grounding for an old garage

[RedTiger678]

Scenario is as follows:

Old house built in the 40's. Addition was added and the panel was moved to the addition, but the contractor (rocket scientists) that moved the panel did NOT upgrade the wiring leading to the old structure, hence there are no grounded circuits. I'm in the process of upgrading the circuits to 14/2 and 12/2 with ground, but there is no access to the panel via attic etc to the new panel location INSIDE the structure.

1. Can I clamp the new grounds to the copper water pipe (Runs about 20 feet underground) and call it good?

2. Should I instead run some conduit outside the structure along a wall to the new panel location and patch the ground back into the grounding bus bar?

My guess is the conduit with ground is the appropriate answer, but wanted to see what other's thoughts are...

 

[7th Kahuna]

I am not an electrician but I think you need both and then of course make sure the panel is properly grounded to a ground rod.
Another possibility would be to provide a grounding rod for the old house alone rather than running it all the way back to the panel. Not sure if it would fly in terms of the code but it would be functional. It'll be interesting to see what others think.

 

[RedTiger678]

The new panel is of course grounded, just don't have grounding wires going to the new structure, simply hot and neutral...

 

[matt151617]

Is the garage attached or detached? Either way, there's simply no way around running wire back to the main panel. You might as well upgrade the feeder line also so you'll have more power if needed. Remember, 4 wires total, and the ground and neutral need to be isolated in the subpanel.

If it's detached, then you'll need to drive ground rods. Ground rods are for lightening protection.

 

[wyliesdiesels]

First off, ground rods, ufer grounds and underground water pipes are NOT to be confused for equipment grounds despite popular misconception! Those are for grounding out lightening strikes.

Having said that, u can use a a PROPERLY grounded metal water line(pipe is connected to ground bar in panel). We do this all the time as a contractor for PGE and their customers here in California who have ungrounded 2 prong outlets that appliances are connected to. Which brings me to my third point- most devices do NOT have a 3 prong grounding plug and therefore dont need a connection to ground in the outlet. The only things that SHOULD be plugged into a properly grounded receptacle are appliances such as fridges, disposals, diswashers, clothes washers and dryers, surge protectors, etc. because for one reason, many of them have metal frames and chasis which could become energized. But its really not worth it to ground EVERY outlet in a house if that's what you're thinking of doing!

EDIT: MY BAD! I skipped over the title and now realize this is a garage youre talking about. The correct answer depends on if the garage is attached or detached. If it is detached, u CANNOT have multiple feeds to a detached building and therefore your only option is to run a main feeder to the garage and install a subpanel. If its attached, then u have a few more choices!

The new panel is of course grounded, just don't have grounding wires going to the new structure, simply hot and neutral...

In your first post u said theres no grounds going to the old structure. Above, u said no grounds going to the new structure. Which one is it?

 

[scot69wilcox]

http://www.diychatroom.com/f18/sub-panel-grounding-13219/

sorry for the link,(united states NEC explanation) but this is the best way I can think of explaining it to you. I am an electrician in Canada, but obviously electrical codes are different in the united states.

call your local inspector, and ask them if any doubts.