Grounding Detached Building


Old 05-22-08, 08:18 PM
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Join Date: Dec 2001
Location: Volusia County, Florida (Central)
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Grounding Detached Building

Have a small building with a 120amp panel fed from the panel from the house about 100' away.

I hired an electrician before I started to make sure I did it right and he told me to install 2-2-2-4 for the panel in a conduit buried at least 24" deep.

Did that, and called the inspector out to verify the depth so I could cover the trench. He told me that Florida has changed without grandfathering earlier permits (mine) required two grounds (I think he said at least 6 feet apart).

Now am really confused.....I guess running 4 wires wasn't necessary.

Exactly what parts, size of rods, depth of rods, how do the rods connect with what to get it into the new panel.

Did a search on this forum, and googled it, and sorry to say couldn't make sense of anything....

Some specific step-by-step would be most appreciated for this dummy who till now thought he was smart......
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Old 05-22-08, 08:31 PM
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Drive 2 8 foot ground rods at least 6 foot apart. These will need to driven so that top top of the rod is flush or below grade.

The subpanels will need an auxillary ground bar kit added. Run a #6 from this bar to the first rod and attach to the rod with an acorn clamp. You may add another acorn and a jumper to the second rod or you can run 1 length and connect to both rods. Only the bare ground from your branch circuits will land on this buss.

The neutrals will land on the neutral buss that comes with the panel. Do NOT install the box bonding screw.

The 08 NEC removed the option of running 3 wire feeds to outbuildings.
Old 05-23-08, 08:27 AM
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Just to follow up on pc's advice, use 8' x 5/8" copper-clad ground rods. Don't use the cheaper steel or zinc rods as those will not meet code for permanent installation.

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