I want to replace my current service entrance panel with a newer 200A unit.

My question is about how to route the wires from the meter and from the house into the new box. All the boxes that meet my requirements seem to have knock-outs on the bottom and bottom side only. I can certainly use a side knockout for the wires from the meter but can I create a hole in the back of the box for the house wires?

I am aware of the height limit to the main breaker and should be good there. Also, does the number of wires coming through the wall look up to code? About half the wires come from below so I thought I could add a junction box inside then run THWN wires up through conduits to reduce the number of wires going through the one bushing but if I don't have to do that I guess I'd rather not.

In short, if you were going to replace this box how would you proceed? Thanks!

existing panel

  • Have you considered keeping the current panel as a sub-panel, and wiring a new main panel next to it? That would save much time, effort, and money.
    – Nate S.
    Commented May 1, 2019 at 21:53
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    What's on the inside of the house, opposite the panel? Is there a pull box there, or do the NMs just come in through the conduit opening/bushing? Commented May 1, 2019 at 23:36
  • Other side of the house is the kitchen. I could potentially put a smaller junction box there but it wouldn't be ideal. As mentioned, about half the wires come from below. That is an unfinished basement so a sub-panel or junction box could easily be put there.
    – goldbrick
    Commented May 2, 2019 at 17:22
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    I don't know where the NM's originate but they just come through the conduit bushing. I assume they are stapled or secured somewhere nearby.
    – goldbrick
    Commented May 2, 2019 at 17:23
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    Nate, don't want to keep the old box, it's really old and I'd rather just replace it all. My latest thought is to put a meter box with service disconnect in place of the current equipment, splice all the wires that are too short to make it to the basement inside this box, then run SER down into the basement and put an indoor sub-panel that would hold all the new breakers.
    – goldbrick
    Commented May 2, 2019 at 17:23

3 Answers 3


You can cut a hole through the back, with a nipple less than 24" long you can fill it to 60%, it's hard to tell from the photo what the fill is, in the past with exterior boxes I have punched 2-3 holes installed bushings and run my wiring from a gutter where I spliced it to some thhn/ thwn and ran that outside. In my last county the inspector felt it was safer not to splice in the gutter and to run the romex into the outside service panel, I would check with your local inspector as they may allow the romex into the service panel (2 out of 3 counties allow this to a nema 3R service panel in my area). The panel must be mounted on the dwelling so the wires directly enter the home.


Right off the bat, you're going to want a BIG panel. You already need 30 spaces just for the circuits you have right now, so a 30 will result in being full on day one. I want to see you have more of a "reserve" than a measly 12, but prices get exponential beyond 42 spaces, so I would stop there and use a subpanel later if you need still more.

Double-stuff breakers (like you have now) won't work anymore. Modern codes require AFCI and/or GFCI on virtually all circuits, and those are not available in double-stuff (as you can see from the one GFCI or AFCI in your panel). So if you get a "20-space/40-circuit" panel, you will have painted yourself into a corner (again). Only spaces will suffice. Also, this panel is a fluke, in that it makes efficient use of space with 2-pole double-stuffs. That's not possible anymore, not even on a GE panel.

If a big panel is too tall, consider regrading the earth around the panel, so you're standing higher on the wall.

Your new panel absolutely needs a main breaker; it's no longer allowed to hot-feed six large breakers as is found in this old "Rule of Six" panel. The size is decided by the power company, not you. Do not let this deter you from getting a large panel. This can be an annoyance if the Power Company wants a smaller breaker (say 125A) than anyone sells in a 42-space panel; however main breakers can be changed, and many "main lug" panels have space to upgrade a main breaker.

Now, I don't know what's on the other side of that wall. But I would put the panel indoors if I could help it. Why? Keeps it out of the weather. Weatherproof panels aren't, although yours has done far better than I usually see.

The cable run between meter and main breaker will be totally unfused. If it has a meltdown or short, unlimited amps will flow, unlimited heat will be made. It can make sense to fit an external main breaker even if you mount the panel indoors. At the least, make sure you are using all metal conduit - PVC fed by an electrical arc will just burn.

I would buy accessory ground bars for the new panel (or buy a panel that comes with), and separate neutrals and grounds (even though this is not strictly required in a new panel). I am a huge fan of wiring the neutral-ground equipotential bond - first a screw thread is wholly insufficient for 500A flow, it will just vaporize; and second, I like being able to clamp an ammeter around the N-G bond.

Looking at this panel I'm concerned with the lack of visible grounds. Now, the metal conduit is a viable ground path, so maybe the ground wires are attached to the junction box on the other side of the wall, that'd be fine. But I also see an awful lot of neutral wires as compared with the hots. I wonder if all the Romex cables are terminated in the box on the other side of the wall, and each wire was extended with black and white (THWN I hope). And then they used white for ground, "since they go to the same bar" being their logic. That is improper, they should've used green (or stripped the wires bare).

  • Thanks Harper. Yep on the AFCI breakers and space requirements. 2 or 3 of the current breakers are unused but I will need more in the future so I'm looking for as big a box as I can find. I think 40 spaces will do but I'll double check before purchase. I also like the idea of an indoor panel and as mentioned above, I'm thinking of moving the panel down below the current stuff and inside. It's an unfinished basement and half the wires are already down there so I'd only need to splice about half of the wires to reach the new panel.
    – goldbrick
    Commented May 2, 2019 at 17:28
  • I called the poco and they told me my service was 200A so I should be good there. If I install a sub-panel downstairs, I'll be sure to use the proper SER. As for the neutrals, they are all twisted together and you can see them just above what I think would be called the neutral bar. Good eye for detail though and thanks again for your thoughts.
    – goldbrick
    Commented May 2, 2019 at 17:30
  • ^I meant the ground wires are twisted together, not the neutrals....
    – goldbrick
    Commented May 2, 2019 at 17:41

Just an update.... I decided to replace this box with a 200A, 8 space, breaker box with feed-thru lugs. I'm going to put 1 or 2 240V circuit breakers in this box but mostly it will be used only for the service disconnect and there will be a separate sub-panel inside the house that houses the majority of the breakers.

I'm hoping to use this enclosure to house the wire splices for the circuits that will not reach the new sub-panel location. I'll update again with pics if/when it actually passes inspection. Thanks for all the help everyone.

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