GE Powermark Electrical Panel - What Did the Last Guy Do?

Question

Basically, I want to do two things - add two dedicated circuits for the garage shop and add a 50 amp 240 breaker for my welder. I've been reading for days about what is going on inside my panel (GE TLM2020). I have, from everything I can tell, have the main panel in the garage. The meter is on the street, but it's all locked up and part of the every-house street light/meter.

The neutral bar is grounded to the box and a ground bar is in place. The ground bar (GE TGL2) has only 14 taps, most of which have two ground wires in each. The neutral bus has two grounds going into it - an aluminum ground from a 50 amp (The range, according to the list) and another ground which appears to go, well, to the ground. I have the 6ga TGL20 tap I need to hook up the welder. I know it goes into the ground bar.

Here is my confusion - the neutral bar is grounded to the box and a ground bar is in place, which tells me it's a main panel, as I've read you can have a ground bar in a main panel as long as the grounding screw (in GE's world, a bar) is in place. But if the neutral bar is grounded, what is the point of the ground bar? Could I, in an effort to get my welder hooked up, move some of the ground wires from the ground bar to the neutral, then use the TGL20 in the existing ground bar? I'm also okay with adding a second ground bar, however, the instructions for the TLM2020 show the ground bar only goes in one spot - the one it's in. But then, they only make a 14 tap ground bar for a 40 circuit, 200 Amp box... Why did the last homeowner decide to use a ground bar in a main panel? Could the Sentry Energy Demand box next to the panel have something to do with it?

I've included a picture (I also have like 10 more as it's too cold to read about the box and stand in the garage). Please feel free to ask me follow up questions or ask for more pictures.

Answer 1

Ground bar fun and games

The original installer's decision to fit a separate ground bar for the ground wires was a good one from a neatness standpoint, even though Code does not take issue with having all the grounds and neutrals on one bar at the main panel, as that's the only place where neutral and ground connect (via that bonding strap you see bottom left).

However, the choice of ground bars and ground bar locations available for your panel leaves us in a pickle. None of the ground bars your panel accepts provide more than 14 connection points, and your panel is not labeled for multiple ground wires in a single ground bar hole as per NEC 110.14(A):

Terminals for more than one conductor and terminals used to connect aluminum shall be so identified.

The only way I can explain this is that your panel predates that marking requirement in Code, leaving us with three not-great options if a subpanel is off the table given that your panel also does not have a factory provision for a second ground bar:

1. Stuff the new ground wires into unused holes in the neutral bar (one large, two small) in an annoyingly sloppy fashion. This is the simplest option, and also the easiest to make Code-compliant right now, but has the downside that it'd make life harder for anyone who wants to convert this panel to a subpanel.

2. Rearrange the wires in the existing ground bar to free up one large and one small hole. This requires a bit of care to get the torquing right, since you are operating outside the loadcenter's labeling at this point, and also is technically a violation of the loadcenter's listing, although not any more so than the current situation.

3. Fit another ground bar to the panel (in-line with the existing bar is fine) and land your wires there, despite the fact your panel doesn't have provisions for this and isn't labeled for multiple ground bars. A GE TGL2 kit can be used for this, although you will have to switch the machine screws used to mount it out for a pair of 10-32 (i.e. fine thread) self-tapping/self-drilling screws, such as Garvin GSSTs. Note that ordinary (coarse thread) sheet metal screws are not suitable for this, as they will not engage two threads into the sheet metal of the cabinet as required by NEC 250.8(A) point 6:

(6) Thread-forming machine screws that engage not less than two threads in the enclosure

Given these alternatives, I would choose the third if possible and the second if not, but this is a case where your local Code inspectors probably can provide more guidance than I can.

Other option: run a feeder to the garage

The other thing I would consider at this point is running a feeder from this panel to a subpanel in the garage. This has the advantage that you will only need one grounding hole free in the main panel instead of a minimum of two, at least, and it also keeps the space usage in this already fairly tightly packed main panel to a minimum.

I would go with a 125A feeder here (using 1/0-1/0-1/0-1 aluminum SER cable and a TGL20 lug in the spare ground hole you free up for this, as well as a 286A8894G1 add-on neutral lug attached to the bar for the top row of neutrals) to a 125A, 30 space panel, in order to provide adequate room for expansion. (Going beyond 125A is rather difficult here due to GE TQDL breakers being hard-to-find, and your panel cannot accept a 150 or 200A subfeed lug block it appears, for that matter, nor will it accept a 200A TQDL breaker.)

Answer 2

That ground bar

The proper way is neutrals on the neutral bar, and grounds on the ground bar, and a neutral-ground bond. I'm a big fan of using a wire for that, because a) it makes burnout much more obvious (a screw head can hide a vaporized screw shaft), and b) you can put a clamp ammeter on it, which will reveal any ground leakage (ground faults). Very useful for troubleshooting.

Builders (i.e. people who build housing units by the thousands) growsed about needing 2 bars since they're connected to each other, so they got NFPA to "bless" an ugly hack where they use one bar for both. This has been the source of staggering misconception, and is the reason my catchphrase on this forum is "Neutral Is Not Ground". Because so many people believe neutral is ground, based on what they see with their own eyes.

Obviously your first exposure was to "ugly hack" type panels, and you've normalized that. No big; just de-normalize it, and know that logically, it is important they are separate.

Given that you have the opportunity, I would separate them completely, fit a hefty ground wire or two between them, and remove the ground bonding screw because as said, I don't trust them.

Imperfect, but not so bad

Since you are searching for bad technique in that box, I see only a few minor issues, mostly style matters.

• Ground screws double-tapped - this is not allowed per GE labeling.
• "Mr. Snippy" cut all your wires short, so you won't be able to move breakers around in the future. Best practice: Leave enough wire so both hot and neutral of every circuit can reach any breaker space in the panel. Neutral for GFCIs.
• way too small a ground bar. This panel is made to be double-stuffed, and can support 40 half-breakers. Best practice: ground holes > possible breakers.
• way too small a panel - this panel counts on using GE's unique "double-stuff" breakers. *Best practice: 40 spaces, since now-required AFCI or GFCI breakers take full spaces.*

The homeowner probably added the ground bar because he knew he'd run out of space lickety split in the neutral bar, or because he's a class act and likes to do things right. He added a small ground bar because that's what GE sold at the time. The Sentry/Sense meter had nothing to do with it; that came along much later as it didn't exist when that ground bar was fitted.

Better ground bars

They really shorted folks on those neutral screws. I wonder if this panel dates back to when grounds were rare (1960s). Nothing wrong with that (except the shortage of grounds obviously).

On the ground bars, I would not hesitate to fit multiple, larger ground bars. Most panel parts must be UL-classified for this panel or it will cause a real problem; however alien ground bars should be safe (if not quite code). See if you're lucky and a 3rd party ground bar will line up with the holes on the lower left (make a tracing). Otherwise just drill and use #10-32 self-tapping screws (10-32 mandatory as ThreePhaseEel discusses). I'd put the ground bar 1.5" from the edge of the panel.

I'm no fan of "screws as grounding path" so I would wire the N-G bond with nice hefty ground wire. I would not run 2 ground wires N-G1 and G1-G2 - if you want to do that, run 1 wire from N through G1 to G2 (hence setting it back from the edge). That way G2's path only involves 2 lugs instead of 4. Given my penchant for running ground wires, why not just use sheet-metal screws? Because some future installer might decide my wire is stupid, and remove it.

Notes on that panel style

GE is the last manufacturer still making a system with discrete half-breakers. (nothing wrong with the concept, it is coincidental that the other makers cheated their UL tests or otherwise made dangerous panels).

Each "stab"/blade has the usual horizontal blade normal breakers clip onto. This type also have a vertical "cruciform" made for GE's half-width breakers to clip onto. Note the "50" in top right is a 2-pole breaker grabbing the cruciform off the stab above it, and the cruciform off the stab below it. It is actually "riding between spaces".

This is a slick system, but it's very important you pay attention to "stab limits" since each stab can have 4 breakers on them. That 50 shares its lower stab with a 20. The leftside breakers are unfilled but imagine there were two 50's there -- 170A on a single stab - whoops! The panel labeling should discuss stab limits.