A friend of mine needs to replace his current Siemens 125A panel with a 200A panel (in the same location), along with getting a service upgrade from the power company. The cost of hiring an electrician for this is quite steep so we're considering whether this can be a DIY job for the two of us, with the right preparation. All existing circuits would remain unchanged.

I'm relatively comfortable with doing a lot of electrical work (running new circuits, using conduit, working in panel, basics of grounding, working with #6 THHN, and familiar with common wiring code), but am not an electrician and have never attempted a panel replacement before. I've watched an electrician do the same job for me before but never did it myself.

If we do go ahead with this, my current line of thinking would be:

  1. Call city inspector to ask about special rules in this jurisdiction.
  2. Call power company to confirm they can run 200A service to his house.
  3. Shut off power at the meter, if easily accessible, or ask power company to shut off power otherwise.
  4. Replace the panel with a 200A capable panel, but leave a 125A breaker in there initially.
  5. Install all breakers.
  6. Restore power to the house.

Once this is done, he can call the power company to request the service upgrade, and then just replace the main breaker from 125A to 200A when that's done.

Does this plan seem reasonable? Anything particularly challenging or not DIY-able here? Also, are there any hidden gotchas to keep in mind if we go ahead with this work?

Some gotchas I'm already aware of:

  1. Might have to add a new ground rod, if the home was built to older standards.
  2. Might have to ground existing systems / pipes if not already grounded.
  3. Only bond ground with neutral in the main panel.
  4. Depending on how the meter is connected, the real "main panel" may actually be outside the house, with the indoor panel being technically a subpanel.
  5. The new panel might need a panel-wide surge protector.

The home was built in 2008, receives underground service, and is in WA state (currently on 2020 NEC).

Current panel

enter image description here

Will post a pic of the box outside shortly.

  • Code has changed, but I do not think just a panel upgrade will cause the need for code upgrades, but #1 is the best person to ask. I am assuming it is to same maker of panel, but check the new panel will take the older breakers( it should,but does not hurt to make sure).
    – crip659
    Apr 26, 2023 at 22:21
  • Tell us a little more about the meter base and the main panel. From the age (2008) I assume that outside the house there must be a box which holds both the meter and a main circuit breaker, and you want to change a "main panel" which is downstream of these? Photos of all the existing panels would be helpful.
    – Greg Hill
    Apr 26, 2023 at 22:29
  • AFAIK in Washington if you're doing just a panel and changing nothing else it doesn't trigger any sort of code update, so that might make your job a lot easier.
    – KMJ
    Apr 26, 2023 at 22:37
  • Whether it's a DIY job is subjective (and therefore off topic), and "any gotchas?" falls under open-ended questions (also off topic). You need to revise to ask something more specific.
    – isherwood
    Apr 26, 2023 at 23:26
  • 3
    Are you able to leave your house without power for days if you encounter difficulties that, without experience, could take you some time to resolve? Will there be any other people in the house, or food in the refrigerators, while you do the work? If so, I suggest this is not a DIY job. Not because you cannot do it, but because you will never gain the experience to become good at it. Leave the once-per-60-years jobs to professionals who do them every day. OTOH if the house can remain uninhabitable for a number of days while you do research and learn, go for it.
    – jay613
    Apr 26, 2023 at 23:44

3 Answers 3


If your pal is doing the service upgrade to accommodate EV charging, it's totally unnecessary. Home EV charging is designed to be "no service upgrade needed". Ask about that.

Now to start with, we are forced to presume the original builder who installed the 125A service used 125A wiring and meter pan. So there are 3 areas which probably need upgrade. The required wire for a 200A service entrance is 4/0 aluminum (which is fine at these large sizes) or 2/0 copper.

  • the service entrance wiring from weatherhead to meter pan
  • the meter pan itself
  • the serice entrance wiring from meter pan to main panel.

Call power company to confirm they can run 200A service to his house.
Shut off power at the meter, if easily accessible, or ask power company to shut off power otherwise.
Replace the panel with a 200A capable panel, but leave a 125A breaker in there initially.

There's a new thing you need to know about.

Some sun-belt cities have had a rule requiring an outside disconnect near the meter, for fire department safety. De-energize the house in 1 place. Meanwhile there's been an explosion of emerging technologies - solar Rapid Disconnect, grid-forming inverters, V2H, V2G, LED enabling DC systems... - and firemen need "1 switch to rule them all". (well, 6 switches, but all in 1 place). As a result, NEC 2020 imposes the sun-belt rule all over North America: Each house must have an outside disconnect.

Why do we care about some dumb rule? Because the effect was to create a market, and commodify a product that would be really helpful here: the meter-main. A meter pan + main breaker in 1 enclosure. You need a new meter pan anyway or at least reworking of the service wires in/out of the meter pan to be 200A instead of 125A... so using a meter-main lets you self-disconnect and do the rest of the work anytime you want, any way you want.

You'll need to run a grounding electrode (ground rods) to the meter-main, and run a separate ground wire to the old main panel and separate neutrals from grounds there, assuming that work isn't rendered moot by the panel upgrade.

And a further evolution of the "meter-main" is the "ranch panel", which adds a mini-panel with 8 breaker spaces to the meter-main. It still has lugs to carry the full amperage onward. It's a great place for generator interlock, solar, surge, EV charging in some cases, etc.

Replace the panel with a 200A capable panel, but leave a 125A breaker in there initially.

Yeah, I'm really "weirded out" by that panel. Look how tall it is.

Panels consist of an "interior" (giant bus assembly/neutral bar) that bolts with 2-3 bolts to the "box", and then a "cover" that matches the "interior". Those are the 3 parts of a panel. There only a limited number of "box" sizes, so it looks like they put a small 24-space interior in a really big box. All that to say... Siemens only started branding as Siemens recently, so it might be possible to find a 30- or 40-space main lug panel that uses that exact same "box". If so, you could buy that panel and swap "interiors" (everything but the box) and panel covers, and not have to mess with the cables going in and out of the box.

  • Thanks! Do you know if meter-mains were in circulation around 2008? What are the steps required to replace / install a meter main?
    – peter
    Apr 26, 2023 at 23:34
  • 1
    @Peter can't speak to 2008. Meter-mains weren't required in 2008 except in some sunbelt municipalities. Replacing a meter-main is the same as replacing a meter pan, which you probably have to do anyway. I edited. Apr 26, 2023 at 23:53
  • In the last paragraph you mentioned we could just replace the panel interior without having to mess with cables going in/out. Does that imply we don't need to get a new meter in the case?
    – peter
    Apr 27, 2023 at 5:20
  • @peter No, it does not. You know if the service was installed 125A, then certainly the builder used 125A kit for a) wiring weatherhead to meter pan. b) meter pan itself. c) wiring meter pan to main panel. I'm adding a mention of that to the answer. Apr 27, 2023 at 21:15

Installation of a new meter-main panel definitely could be intimidating. I've done it twice (my current home and the prior one). I'm not an electrician but have enough background that I might talk the talk well enough that the average person would believe if I bluffed that I were.

First house.. easy!

The weather was mild and the home was vacant. I spread the work over a couple of afternoons. I had just purchased the place and it had no main at all. I don't think it was even a rule-of-6 arrangement! My home owner insurance required that a proper main be installed; I elected to use a meter-main style panel. This was in 2008 and as I recall meter-mains were fairly common here at that time. Utility supply was overhead and the process went like this:

  1. Get electrical building permit from city
  2. Set an appointment with electric utility to have power disconnected. They removed their meter, cut the overhead drop wires at the splice just outside the old weather head, and left the drop wires in place with the messenger/neutral wire anchored to the fascia on the edge of the roof.
  3. Remove old mast and meter base
  4. Install new meter main positioned so that new mast went up in the same place as the old one
  5. Install circuit breakers and feeder cable to supply power into the original/old breaker panels, which were able to remain in their original places on the wall
  6. Drive new ground rods
  7. City inspection
  8. Call the utility and ask for re-connect. The lineman spliced my new mast conductors to the old overhead drop conductors, popped in the meter, and went on his way.

Second house.. major stress!

My family and I lived in this house at the time and I got the hare-brained idea to do the upgrade in early December. The house had what I'll call a main disconnect panel: a meter socket on the right, one big 200 amp breaker on the left, and a fat cable going through the wall to a subpanel in the middle of the house. Utility supply was underground.

I chose to install a "ranch panel" as Harper calls them: a panel with the meter socket on the left, and on the right a big 200 amp breaker at the top, a handful of branch breaker spaces in the middle, and feed-through lugs at the bottom to which I could attach that fat cable feeding my subpanel.

The exterior wall was finished with stucco around the original panel, not behind it. The new panel covered a larger area than the old one and I wanted to ensure it overlapped/concealed the unfinished wall surface. The old panel had the meter on the right but the new panel had its meter socket on the left. I excavated about 10 feet of the underground service conduit so that I could re-position the riser. December is winter here, so of course it was cold and windy. And it snowed lightly all day. So the dirt was muddy, my fingers could hardly move, and I stood on a plank laid over the trench so I could work at grade height while wrangling the new panel. It was awful. I had a goal to get power restored same-day and it went something like this:

  1. Get permit from city
  2. Expose underground supply conduit (done a few days in advance)
  3. Schedule appointment with electric utility for service disconnect. They arrived on the appointed day but not until like 10:30 am. They removed the meter and disconnected the underground conductors in the splice box by the road.
  4. I set up a portable generator to keep the essentials powered through the day (fridge, freezer, furnace, some lights, etc).
  5. Remove the old panel
  6. The underground conduit needed to be shortened so that the riser could move about a foot to the left of its original position. I carefully cut the PVC without damaging the conductors inside. It was only 2" conduit, so getting it pulled off the 4/0 conductors was a significant struggle. I removed a section of the conduit, slid on a new adapter, and wrestled even more trying to get the conductors back into the riser...
  7. Have you searched for the phrase "swear words" on DIY? Practically all of the results are in questions related to electrical conduit! (Incidentally, the first 8 I found were all authored by Harper, cautioning people that "if you don't know enough swear words, you may have to call in an electrician who knows more of them than you do.")
  8. Hang the new panel, wrestle the service riser into place.
  9. Cut a hole in the drywall on the other side; re-position the fat 4/0 feeder cable so that enters the correct side of the new panel
  10. Call for the city inspector somewhere around 2-3 in the afternoon
  11. Fail the inspection, but the inspector gave the "approved to connect service" sticker anyway with my promise to correct the deficiencies and call him back in a few days
  12. Call utility and request re-connect
  13. Somebody arrived in the early evening to connect
  14. Continue work to correct the problems, but at least the service was connected and I could now turn my new main off, do some work, turn it back on, etc.
  • This is really useful, thanks! Weather aside, would you say the underground feeder job should have been easier?
    – peter
    Apr 28, 2023 at 18:50
  • @peter The reality is that, despite all the stress and the moaning about the weather, it was only about 8 hours that the PoCo service was disconnected. I had rehearsed the project in advance to identify parts and tools I might need. It would have been significantly easier had I not decided to move the underground riser, but other than that, it really did go well and couldn't have been much easier.
    – Greg Hill
    Apr 28, 2023 at 20:07

I won't repeat answers given but will definitely reiterate that 200 amp service will require a new meter pan and mast (if overhead wires). The overhead wires will most likely remain (very often the service entrance cables are rated for 200 amp service). But a new mast will require power to be cut off at the street. You are then responsible for the splice from the mast to the SE cables and it has to be to utility company standards. This is not a DIY project.

  • The house gets underground service so I don't think there's a mast. It sounds like that's not necessarily easier, but perhaps the "responsibility for the street level splice" means less that can go wrong?
    – peter
    Apr 27, 2023 at 5:28
  • Underground service doesn't have a mast, but 200 amp service from 100 amp service still requires a new meter pan and feed to the panel. The utility company will disconnect power and you are responsible from the meter pan to your panel. Your project would be much easier and within an advanced DIYer abilities if you weren't going to 200 amp service. Be well. Apr 30, 2023 at 23:47

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