Adding panel in out building,

Old 06-24-16, 10:35 PM
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Adding panel in out building,

I'm in the midst of a new project (constantly) adding a lot of lights to our garden and wanted to change the electrical set up to get everything off the same circuit

The current set up is that a circuit from one of the main panels runs out through a conduit in one of the perimeter walls to an out building at the back of the property. Along the way it feeds some lights and an outlet at the building (small pool house type structure) it feeds some more lights and then is spliced to a direct burial cable which feeds a single circuit breaker in the pool pump housing.

The whole shebang is protected by a 16a breaker

What I'd like to do is run the circuit from the panel to the outbuilding through the existing conduit. Add a subpanel there with 3 breakers or so (lights, pool, building).

What I'm not sure about is if I need to take current circuit breaker out from "behind" the GFCI breaker when I add the new panel. I'm going to be installing a GFCI in the sub panel. Is there any problem with having one behind the other?

If I do have the two chained will a ground fault at the end of the circuit trip both? Because that's what I'd like to avoid.

Also there is currently no ground wire in any of the back yard wiring although a multimeter confirms a consistent 220v between hot and the junction boxes, I'm planning on pulling a ground wire through the conduit unless there's any reason why I would need to have a new grounding rod installed by the back building (its less than 150ft from the house).

And finally joining that new ground cable to the ground. Unlike most american panels my panels have no ground bus, they just have a piece of naked twisted copper which runs through the house and the panels. In the lower panel this twisted copper is clamped in two places to a piece of rebar that looks to have been pried from the surrounding wall before heading down through a flexible plastic conduit to a grounding electrode in a closet in the laundry room about 5 feet away.

To join the new ground wire, could I just strip the insulation pretty far back, wrap it around the existing ground, twist to tighten and secure with a cable clamp?

Here's a drawing of the current set up for reference. The question marks are I'm not sure if the ground being clamped to the rebar means that the rebar is an ufer ground. Also while I can see that there is a grounding electrode just below the electric meter I don't know if the neutral is bonded there or somewhere else.

Old 06-25-16, 07:49 AM
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