I recently bought a house which has a detached garage. The previous owners wired the garage themselves, but neglected to bring the ground wire from the service panel, so the garage was ungrounded. Not wanting to be the ground, I installed a ground rod. Before I attached the ground wire to the rod, I wanted to test if there was any voltage coming off the ground wire. I used a meter and touched one probe to the ground wire the other to the rod, and sure enough, I'm reading thirty volts. I wanted to see what kind of current it is producing, but when I set to test for that, I'm not even drawing one milliamp! I think I have some "phantom voltage" - my ground wire has 30 volts of pressure but no current running through it. I can even hold the ground amp, while I, too, am grounded, and nothing happens. Is this normal?

Thanks,

Sean Conaway

The voltage you have will be from a incorrect or poor grounding done at the one or both of the panels.

First we need to insure the panel is grounded properly, Where does the ground wire from the rod connect? To the metal can and equipment ground bar in the panel?

Only if the feeder conduit is plastic, and there is no other metal path between buildings such as a water line or telephone lines:
The neutral must be bonded to the metal can using a screw that is driven through the neutral into the can, Or use a jumper from the neutral bar to the metal can.

The grounding at the main panel must be the same. And be sure the connection to the ground rods and or city water at the main panel is in good condition.

Check these conditions, rewire as necessary and the issue should be solved. If the grounding is not done or cannot be done as I explained get back with the exact details.