I opened up this subpanel for the first time because when I opened the walls for contractors to install floor drains, I found a circuit with four splices that were any/all of:
- not enclosed in junction boxes
- did not use wire nuts
- tapped into NM cable rather than cut and spliced
- no ground wire in sight; all 12/2 without ground cable
Fortunately, that particular work appears to be isolated to a single circuit so I decided to replace the cable from the subpanel breaker.
The subpanel, however, is ungrounded and all the neutral and ground wires are bonded to neutral. And other problems – I am particularly amused by the cable routed over the edge of the panel rather than through a knockout. It does not have a master cutoff although the panel is on its own breaker in the main panel.
Can this panel be brought up to code by adding a proper ground bar and ground conductor back to the main box, or am I looking at a subpanel replacement project here?
Best Answer
New subpanel time
The reason is, there are several structural issues with how this panel is mounted, so it has to come out anyway. So you might as well put a proper panel in here. And believe me, it'll be a relief!
The structural issues are:
Separately from that, the panel is way too darn small, and I know this has been impacting your project, in ways that you've just been working around up til now. Like the insanity with the bathroom outlet feeding a lot of other stuff, I'm sure there's a lot of that going on. I mean the subpanel got put in in the first place because the main panel was full; and it's full too. Not good. You should always have loads of extra space.
You need to make the call on size, but we beat the drum hard for Big Big Big. I for one like to see around 48 spaces between both panels. Absent better information I would call for a 30-space. Space not circuit; a 20-space/40-circuit panel only counts as a 20.
A main-lug panel will suffice, and you can mount it inverted if the existing wires will not reach. Bus amperage doesn't matter. You can stay with Square D "QO" if you want to reuse your breakers and pay 60% above market for any new breakers. One advantage of QO and Eaton CH is the breakers are only 3/4" tall, so panels are shorter for the same number of breakers. Either get a panel with included ground bars, or add them.
Retrofit a ground wire between the main panel and subpanel. The old cable is fine unless you want to up-size it; if you do, go aluminum.
If you keep it
First, keep in mind that work is not necessarily grandfathered merely because it is old. It's only grandfathered if it was correct at the time it was installed. Many a dryer and range circuit is run with /2 w/gnd NM cable, which was never legal.
If you look at the list at the top, that's pretty much your punchlist. First and foremost the panel must be de-installed to move it outward so it 1/16" proud of the wall so the cover can bottom out on the panel body. If you want to have little hatches above and below it for access to the wires, that is fine. Then it either needs to be repositioned so the sheath of each cable can enter the box by at least 1/4", or you need to terminate those cable runs in a junction box above or below, then bring it on into the panel with a jumper. I prefer to connect the junction box with an EMT conduit nipple (short pipe) of about 2" and bring the wires into the panel proper via the EMT. You might even be able to do it with existing wire length.
Further, the neutral bar must be addressed. You can't finish the job with 2 wires in any slot. Some panel makers allow 3 on ground wires, but nobody allows double-lugging neutrals. I can't see how you can need more than 12 neutrals in a 12-breaker panel, though. All the grounds need to go, for that and separation reasons. Quite likely a common Square D ground bar will bolt up to this panel into existing holes, but your Square D dealer will know for sure.
A Square D dealer means a real electrical supply house. The big box stores don't even own the correct catalogs, let alone have any experience interpreting them.