3

At my house, there is a subpanel that serves a pool area, served by one 30 amp 240v circuit. The panel, which I think was installed about 30 years ago, has just one bus bar that the neutrals and grounds are both connected to. The service neutral and ground wires are connected to the bus bar at opposite ends. This gives the appearance that the neutral current is run through both the neutral and ground wires back to the main panel, which I know is the wrong way to install a subpanel. Now, I've had this house for more than ten years and never had any problems with this, but I'm wondering, should I change this, or am I just misunderstanding the layout of the panel? This is the only breaker box I ever recall seeing with just one bus bar, and I'm wondering if there is something to it that I am missing. If not, I'm assuming the thing to do would be to purchase a new bus bar, install it in the panel, and run all the grounds (or neutrals) to it, and use it to separate the ground and neutral currents, right?enter image description here enter image description here

EDIT: Here are photos of the box. Can anyone identify the make and model of the box? Note that some of the circuits have been disconnected from the breakers in the interior shot of the box due to the fact that I am doing some work. (There were some other things that were not installed properly that I am in the process of fixing). The main ground is the green wire on the far left.

  • 2
    What make/model is the breaker box in question? Can you post photos of its label? – ThreePhaseEel May 18 at 13:41
  • 3
    Yeah, probably the installer bought some random panel that was cheap, saw that there was only a neutral bar (because that one requires you spend for an extra ground bar) and either thought that's just how you wire stuff, or lazed out. Either way, in a pool area it's super hazardous. I mean it'll work until it doesn't, but when it doesn't, you have a much higher chance of fatality. – Harper May 18 at 13:53
  • 1
    I don't know the make and model (the box has been outdoors, and the label on the inside is completely gone). But I'll post a photo as soon as I can. However, I'll go ahead and describe it. The box contains eight slots positioned next to each other horizontally. The door to the box opens upward vertically. Inside the box, the neutral/ground bus bar is positioned horizontally above the breakers with the main ground connected to one of the regular screw-in holes, and the neutral connected to the terminal of the bus bar. The panel is located next to the pump, and we are about to enclose the area. – Sagierian May 19 at 5:56
  • 1
    @manassehkatz -- for an outdoor (NEMA 3R) box, the lid is supposed to hinge upward (at least, that's the norm for most cutout boxes and all N3R LC enclosures I've seen) – ThreePhaseEel May 19 at 22:49
  • @ThreePhaseEel You would know a lot better than me. There is one piece of logic to an upward hinge - better protection from weather. And a quick search on Home Depot shows that to be typical. Deleting my earlier erroneous comments. Though it still seems a bit of a poor design as I described... – manassehkatz May 19 at 22:52
4

You are correct in your assumption that your neutral and grounding conductor must be separated in subpanels per the NEC which only allows neutrals and grounds to be attached on the same bus in the Main Panel with a main circuit breaker. You or a contractor should go out and purchase a second bus and separate the conductors.

I can also say that your situation is not uncommon in the industry. This subpanel was probably installed by the pool company and whoever installed it had limited experience.

The question most people ask is, is it safe? The only answer I can give someone without a seminar, is that it is less safe the way it is and it does violate the NEC. So you have discovered it and it should be corrected.

  • Thanks. Looks like I will be getting a separate bus bar for the grounds, but I'd like for someone experienced here to take a look at the photos I posted and see if there is something I am missing. The person that installed this was definitely not a professional electrician, and did a bunch of other things wrong that I am in the process of correcting. – Sagierian May 20 at 1:49
4

Get a PK7GTA and clean this mess up

Your panel appears to be a Square-D QO612L100RB (of unknown series, though). The correct grounding bar for your panel is a Square-D PK7GTA; this should be pretty easy to find at any electrical supply house that carries the Square-D product line, and shouldn't cost more than $10.

With the feeder breaker off, you'll need to remove all the ground wires (bare and green) from the neutral bar, remove the green bonding screw from said neutral bar, install the new ground bar, fix the dodgy splices on the bare ground wires with some wirenuts, and attach the ground wires to the new ground bar.

2

Given that it serves a pool area, you really, really, really want GFCI protection: it's cheap liability insurance. That can be either as

  • a 2-pole GFCI feed breaker in the main panel
  • replacing this with a "hot tub" subpanel that includes a GFCI main (but finding a 6-8 space hot tub panel will be hard), or
  • GFCI breakers in each slot (which will preclude use of the double-stuff breaker in space 5, since GFCIs/AFCIs are not available in double-stuff).

I prefer the first solution, because it protects all the wires in this subpanel.

Make sure there is a deadfront for this panel (i.e. the plate that covers the wires but leaves the breakers exposed). If there isn't, see if your friendly neighborhood Square D dealer can sell you one, or just replace the subpanel altogether. (That doesn't look like it'd be a particularly hard job, given the small wire connections and mostly flexible conduit). If you get a "QO" family subpanel you can reuse the breakers. You could also think about getting one with more spaces; that one is stuffed and starting to be "double" stuffed :)

Also, plug the empty knockout holes with knockout covers. Deters weather and curious fingers.

On the conduit run in the lower right, it appears the red, white and ground wires are individual wires. Regardless, they are too short, and the run should be replaced unless you can liberate a lot of length from the far end.

If the lower right pipe has two cables, it is grossly overfilled. See if you can replace one or both cables with THHN wire for the segment which is in conduit.

Also I see Romex cable in there; it's not outdoor rated and needs to be replaced with individual wires (if all in conduit) or UF (which is outdoor rated).

Lastly, given the number of faults I see above (and others discuss), I would treat everything about this installation as suspect, and go over it all carefully. Notably, make sure the breaker on the feeder wire is appropriately sized for the feeder wire.

  • As I already mentioned, the person that installed this did a bunch of things wrong. One thing they did wrong is they ran two separate 120v circuits through a 10/3 wire intended for a single 240v circuit, and used the same neutral. The insulation was stripped off the wires in the conduit, which is why the wires appear separate where they come in the box. I'm not going to try to fix this, as it works ok (and would be nearly impossible), but if something were to go wrong, I would just run entirely new wires to the circuits. Also, I'm planning on running two new circuits through the empty holes. – Sagierian May 22 at 2:04

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.