Questionable shop wiring

10 years ago

Hi folks. Just bought a house and passed inspection without questions. However, I neglected to pay to have the shop inspected. After trying to troubleshoot a few lights and switches that aren't working, I think I found the culprit. Looks like the previous owner was running two 120v circuits off of a 240v breaker. Half of the lights in the shop are working, half are not. The half that are working are tied to the red wire in the attached photo. The half that aren't are tied to the green wire. When I plug a 3-wire receptical tester into the outlets that work, it shows normal. What is going on here.. It appears he used both legs of the 240v breaker as current carrying conductors, and pig-tailed all of the neutrals together. I see the white wire coming out of that port in the bottom right corner, and back to my neutral bus in the panel... Probably. I would appreciate any clarity. I don't intend on doing any work myself, but I am very curious and would love to learn WTH the previous owner was doing here. Also, if the current setup is considered safe, and what it would take to get the other bank of lights running. Thanks in advance!

Featured Answer

rwiegand

10 years ago

There's some odd stuff going on in your pictures -- a green wire going to the breaker (green is typically reserved for the ground)? and some very different size wires connected together -- almost certainly not rated for the 30A of the breaker. So you have problems that need to be fixed.

But the concept is called a multi-wire branch circuit, and is a completely legit and normal way to provide 240 and 120V circuits in a shop. You typically run 3 conductor plus ground wire from a 240V breaker. To get 240V you connect your 240V outlet to the two hot leads, +120 and -120 giving 240 V; for 120 V you connect one of the hot leads (typically the red or black) and the neutral (typically white). It is a very convenient, safe, useful, and completely code compliant method. Running what looks like 14 ga wire on a 30 A breaker is not.

If you want to keep the 15 A circuits you're going to have to drop the breaker size to 15A, or run a new 15A feed to them. If you need a 30A circuit then all the wire and devices on the circuit need to be sized for 30A. Most shops would be wired with 12 ga wire for all of the normal outlets using 20 A breakers, with dedicated breakers and runs of 10 ga or larger as appropriate to machines needing more than 20 A. (except perhaps for a large air compressor that would be unusual in most home shops; a 240V 20A circuit is sufficient to power most motors up to ~ 5 HP).

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Comments (11)

randy427
10 years ago
With the green wire being used as a hot lead, where is the ground connection to the breaker panel? It must be green or bare. I know of no exception to allow for the green wire to be used for other than ground in a residential 120/240 volt circuit.

I also have doubts about those GE breakers being the correct ones for that panel.
seamale thanked randy427
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Ron Natalie
10 years ago
I agree with the other posters.

1. It's illegal to use green wires (even if remarked) for anything other than ground.

2. There appears to be no ground connection from the panel to the smaller circuits.

3. The breaker is oversized for the smaller cables after the junction.

4. Something is wrong with the breakers in the panel. There's no way that GE and Type BR (look like old ones at that) breakers go in the same panel.

Someone took a single 30A 120V circuit and tried to make a MWBC out if it but did so in an ILLEGAL an complete UNSAFE manner.
seamale thanked Ron Natalie
rwiegand
10 years ago
Looks like you've also got neutral and grounds connected to the same bus bar. Call thee an electrician!
seamale thanked rwiegand
greg_2015
10 years ago
If it's the main panel, there's no problem having the neutral and grounds on the same bar.
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mike_kaiser_gw
10 years ago
I can't tell for sure but the connector at the bottom right of the service panel. The large wires appear to be red/green/white but there also appears to be a separate, smaller NM cable. I'm assuming the individual red/green/white wires are run in conduit or flex. How did the NM get in there because it doesn't seem to show up in the junction box.

Maybe I can't see it but shouldn't the ground wires in the junction box be connected to the metal box as well as each other?
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Ron Natalie
10 years ago
Yeah, it does look like (at both ends) the wires emerge from a busing indicating some sort of conduit (not that it makes any difference).

The junction box grounds (other than the bootlegged green wire being used as hot) are connected together. They are joined by the red wirenut in the lower left side of the junction box. The box itself probably isn't grounded (yes it should be) and nothing apparently connects the grounds of these "split off" circuits back to a real ground (the conduit fitting on the box side appears to be plastic, so I doubt that the conduit is an effective ground).
seamale thanked Ron Natalie
D G
10 years ago
Is the junction box in a location where a welder or other larger piece of equipment could go? To me it looks like person A wanted an outlet for a welder or compressor, person B decided he didn't need it and wanted lights, and person C which is you now has to clean up a mess. If it is easy to just gut it if not abandoned it and run conduit from your breaker to your lights and do it properly.

Out of curiosity where is the junction box located? I noticed the 2 x 4 is cut just below the box and it looks like the box is resting on a shelf created by the cut.

I just noticed that the colors he used are the same as the Italian flag. He wasn't Italian was he? :)
seamale
Original Author
10 years ago
Thank you all for taking the time to look at these. I should clarify there is no 240 outlet in the shop. Also, the only wires available in the shop are red, white, green. I'm unsure of the gauge, but I will measure. It is likely 12, but as rweigand mentioned, some of those pig-tailed are smaller wire. So, my safest and cheapest bet here is to have someone replace the 30amp breakers with 15/20amp based on gauge and run-length and run this as a single 120v circuit? Seems like that would be up to code regarding the wires I already have in place? Also the wiring in the junction box would need to be adjusted so none of those wires were trying to use green as hot (....).
seamale
Original Author
10 years ago
last modified: 10 years ago
@D G, He might have been! Haha, I'm not 100% though. The junction box is on the far wall of the shop, fed by a flexible non-metallic outdoor conduit (looks like a sturdy rubber hose) run below-ground from the main breaker. There used to be a 240 outlet in the shop (the plug is still there, currently not wired to anything) so I bet you're right.
Ron Natalie
10 years ago
This appears to have been a 30A 120V line that was bogusly split. Just as GREEN isn't legitimately anything other than ground, WHITE should not be anything but the grounded conductor (i.e., neutral). Of course, it would only be slightly less bogus that they hooked a 240 outlet up to BLACK-WHITE (and groudned the GREEN). Electricity doesn't care much about the wire colors. What you have however is completely unsafe: too big overcurrent and no ground.
seamale thanked Ron Natalie