unsafe wiring to shed?

lawsklsux

I have 12-2 with ground running from my service panel underground to a shed. I am rewiring the shed to better suit my needs. At the shed, there is a junction box bringing the underground run into the shed but the wiring there is confusing me. The neutral from the underground run is capped off with no connections. Then the neutral and ground from the shed wiring connects to the ground from the underground run, which in turn is connected to both the metal junction box and a grounding wire running outside the shed to a stake in the ground. My questions: Is there any reason why the wiring would have been done this way? Isn't it unsafe to connect the neutral and ground in that way and should the neutral of the shed wiring be connected ONLY to the neutral on the underground run, then the grounds all be connected the way they are? Thank you for any help you can give.

Scuba_Dave

Neutral should be connected at the shed
Neutrals & grounds must be kept separate under today's code

a7ecorsair

You might want to verify that the white wire is connected in your main panel. Is the ground stake an actual grounding electrode or just some piece of metal hammered into the ground?
You should disconnect this ground and just wire your shed using the underground cable. Is this shed served by its own 20 amp circuit breaker?
You should also verify that the 12-2 is UF and you will need a disconnect switch at the shed.

lawsklsux

Good point - I will check the white wire. The ground stake looks like a piece of rebar pounded into the ground. The shed has its own 20amp breaker and the 12-2 is UF. It does not have a switch at the shed. I don't really want to put in a subpanel - is there a different type of shut off switch I can use?

McSteve

Sounds like whoever originally wired it didn't know what the heck they were doing. Or, the neutral in the UF cable got broke somewhere, and whoever fixed it didn't know what the heck they were doing.

Get the neutral and ground separated like they should be, and see if it works. If not, probably the neutral is broken in the cable and it'll have to be replaced.

As far as a disconnect goes, you can just wire in a 20A light switch where the power comes in to the shed, and write "Main Disconnect" on the switch plate.

lawsklsux

Thank you. Since the ground is insulated in the UF cable, if the white is broken, can I use the ground as replacement for the white, then ground out the shed wiring to the rebar ground. I would have no ground running back to the panel but I would have a ground. Re-running from the panel out to the shed would not be a fun project.

McSteve

In a word; no.

You would basically have the same situation you do now, except with no equipment ground at all. This is a really common misconception regarding grounding.

The ground rod at the shed does nothing as far as an equipment ground goes. The equipment ground's purpose is to allow fault current, for example from a broken hot wire touching the frame of a power tool, to return to the main panel and trip the breaker. Without it, the power tool will simply have an energized frame, and happily electrocute you.

The ground rod is primarily for lightning protection, to give a lightning strike a relatively safe path to the earth.

Hopefully, the neutral isn't actually broken in your cable, and it was just a horrible mistake on the part of whoever originally wired it. If it is, though, I'm afraid you're going to have to dig.

If it does come to that, I'd suggest burying a 1" PVC conduit instead of UF. That gives you some more options down the road, and will probably last much longer than UF cable.

lawsklsux

I checked the neutral and it appears to be fine - don't know why someone did it that way but I will use the 3 wires correctly. Thanks!