In Seattle in the US, I currently have a 24" tall split bus 200A electrical panel and I'd like to upgrade to a 36" panel for more capacity and to get main breaker. Unfortunately the laundry sink (you can see the lip of the sink in my photo) vent pipe runs below the panel and can't be lowered much since it's barely 6" above the flood line. What's my best option here?


Edit: removed the table

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Edit 2: here's the current panel

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Things I've considered:

  1. Let the electrician take off the existing panel and frame a one stud-wide wall in front of the panel. Not sure if I need to insulate or add a moisture barrier behind it.
  2. Let the electrician take off the existing panel and nail some 2x5s or 2x6s to the sill and a sheet of plywood on top of that to mount the panel, which just hangs in front of the vent pipe.
  3. Move the service to another location. This sounds expensive and requires exterior work too.
  4. Move the laundry sink/washer/dryer elsewhere. This also is expensive and requires exterior work to move the dryer duct.
  5. Some other creative solution.

Thanks for the advice!

  • 1
    That bench can't be there. There needs to be a dedicated space roughly 30x30 square x 78" tall for the electrician to stand to service the panel. All the time, or trivially rollable away in 5 seconds, not "oh my gosh let me find places to put all the stuff on this table and all the boxes under it and the table too". Jul 7, 2018 at 16:40
  • The bench was the first thing I noticed also +. The horizontal vent is tough to tell it may also be a current code violation so a sub panel to the side would probably be the route I would suggest if you only want more breaker spaces. You should have a main or disconnecting means outside.
    – Ed Beal
    Jul 7, 2018 at 16:46
  • Thanks! I will move the bench. It doesn't need to be there. Yeah based on my reading of the code the current vent pipe doesn't even conform since the cross sectional area underneath the panel needs to be clear to the ground (and 6'8" up). Just trying to figure out how to get a taller panel in. Thanks for the subpanel idea. I thought about this but didn't know how to weigh having two one main and one subpanel vs. just a single panel.
    – Steven
    Jul 7, 2018 at 16:53
  • What is the manufacturer of this split bus panel? @Ed Beal what would be involved in getting a main or disconnecting means outside? I would say that even without wheels the table is trivially movable if it has nothing stacked on it. This table looks functional for processing clothes. There is an open space for a 2-pole breaker in upper right and a sub-panel to the right would seem to be the cost effective solution if the existing panel is from a good manufacturer. Jul 7, 2018 at 17:20
  • @Jim Stewart anything in front of the code restricted area of 30" is a violation other than electrical gutter and it can only be 6" if memory serves. This has been code for many years (floor to ceiling 30" wide or the width of the equipment but most are not 30" wide).
    – Ed Beal
    Jul 7, 2018 at 17:30

2 Answers 2


I would go with a variation on option 2

I would notch two pieces of 2x6 pressure-treated dimensional lumber to accommodate the plumbing (vent and waste), then stand them on a 2x6 pressure-treated sill lagged to the floor with the "studs" 16" apart O.C. From there, you can then install 2x6 blocking (top blocking on edge, bottom blocking on the flat) between the bump-out "studs" and surface mount the new panel to the blocking members, thus placing the vent and waste lines outside of the 110.26(A) clear working space.

If this "mini-wall" proves impractical, there's also the option of using angle brackets and tie plates (Strong-Tie type ML angle and type TP tie plate, or equivalent) to mount notched 2x6 side blocking on edge to the existing studwork and boards for at least 48" from where the top blocking goes, and then mount the top and bottom blocking boards as specified below.

As to your new panel, I would set the bottom blocking member to accommodate a 43" to 48.5" high box -- this provides room for a 54 or 60 space loadcenter, depending on whose loadcenters you go with (Siemens has a 54 space option that is reasonably priced, while Eaton offers 60 spaces in both their BR and CH lines, and Square D offers both 54 and 60 spaces in QO and a 60 space option in Homeline as well).

As to why a subpanel is probably unwise

The NEC prohibits the classical "split bus" panel configuration with a rule-of-six main disconnecting means forming the top bus structure and a subfeed from that main disconnect powering the bottom bus structure in 408.36 Exception 1:

Exception No.1: Individual protection shall not be required for a panelboard used as service equipment with multiple disconnecting means in accordance with 230.71. In panelboards protected by three or more main circuit breakers or sets of fuses, the circuit breakers or sets of fuses shall not supply a second bus structure within the same panelboard assembly.

As a result of this, you'd need to fit a main breaker somewhere in line with the existing panel to make it conform with current NEC standards. However, since your panel does not have a place to mount a main breaker in place of the main lugs, and there is no space above the panel to mount a main breaker in a separate enclosure, you would have to use a backfed main breaker configuration, and that poses two problems for you:

  1. GE split-bus interiors likely do not support hold-downs (I checked with GE tech support, and they weren't able to provide a definitive answer, but were skeptical of it working) for backfed mains, and said hold-down kit (a TQDLRK in your case) is required by NEC 408.36(D):

(D) Back-Fed Devices. Plug-in-type overcurrent protection devices or plug-in type main lug assemblies that are backfed and used to terminate field-installed ungrounded supply conductors shall be secured in place by an additional fastener that requires other than a pull to release the device from the mounting means on the panel.

  1. The correct main breaker for your panel would be a TQDL21200 (or equivalently, a Midwest Electric CB2200B), but that breaker is a bit difficult and costly to obtain. It also would take up all 4 spaces at the top of the panel; this means that you'd have to use a 200A feeder connected to the panel's main lugs in what's effectively a feed-through lug configuration, instead of a more normal setup with a feeder breaker.

Double the loadcenters, double the fun

Adding an extra "stud" or side-blocking member to the support configuration would provide space adjacent to the replacement load center for an additional loadcenter. This could be connected in a "daisy chain" fashion, using a subfeed lug block in the first loadcenter, jumpered using fat wires to the main lugs on a second loadcenter, or as a traditional subpanel.

  • The way I read your quote is the split bus panel is no longer approved for installation, but if it is there isn't it grandfathered in? And it is not prohibited to add a sub-panel to a grandfathered split bus panel, is it? For very little cost a DIYer could add a sub panel, but a new panel will cost probably > $2k. Of course, if the house were being offered for sale, prospective buyers might be put off by a grandfathered panel or a home inspector flag it as a deficiency. Jul 7, 2018 at 21:26
  • @JimStewart -- since I'll be contacting GE tech support on Monday, I'll ask them directly if their split-bus interiors can take a backfeed hold-down kit. Of course, the rather poor availability of GE branch breakers > 125A is also a consideration here. Jul 7, 2018 at 21:54
  • @ThreePhaseEel thank you for the detailed answer and background on subpanels! There are some minor challenges with lagging basically a mini-wall to the foundation, but I hope all solvable. (1) The bottom drain flares out in front of the basement floor vent so may be quite a bit out from being directly underneath the horizontal vent; I can probably revise this section under the panel to run in line with the vent. (2) The footings protrude above the foundation so my wall will need to be ~1" out. (3) The foundation is sloped towards the drain, so I might have to have two different length studs.
    – Steven
    Jul 8, 2018 at 6:34
  • What is the difference between the Eaton BR and CH lines? Do these have a space for the Eaton whole house surge protector? Jul 8, 2018 at 17:26
  • @JimStewart -- poke me in DIY.SE chat about that one, it'll take more explaining than will fit in a comment Jul 8, 2018 at 17:32

I would go with option 5 and maybe combined with option 2. First I would get rid of the split bus panel (They are no longer legal for a reason). Second I would install a two or even three section panel. This are not sub-panels the first panel has an MCB and then the other panels are lugged from bus to bus with a full size conductor.

You will be able to find these from a wholesaler as they are not a stock item.

Good Luck.

  • A have seen an arrangement by a good quality builder where the master breaker and all the 2-pole breakers were outside on a wall of the garage in a box with the meter. A cable through to the garage connected to a panel with all the 1-pole branch breakers. The inside panel had a knockout for a master breaker but there was none. Seems odd because many homeowners would go into the garage, see the panel, and expect to handle any situation there. I would think that at the least there should be a master breaker for the branch circuits in the box with all the branch breakers. Jul 9, 2018 at 11:21

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