Neutral and ground connected to one bus bar in subpanel; should I change?

Question

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?

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.

Answer 1

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.

Answer 2

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.

Answer 3

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.