I asked this question in a convoluted way and didn't get any answers, so I thought I'd ask again and make my question clearer with more images.
I have a 150 amp disconnect at the meter. The box only has the 150 amp disconnect with no additional room (see picture). The 150 amp sub panel inside the house is full.
I'd like to upgrade that box with 200 amp service and some room for additional breakers.
Can I install a 200 amp box like the image below, then add a 150 amp breaker (also pictured) for the 150 sub panel in the house, leaving me with additional space for more breakers?
@Tester101: to answer some of your questions and address your points: 1) The overhead conductors that run from the pole to the meter are adequately sized for 200 amp service 2) The meter and the disconnect are in the same box (as shown), so the issue of adequately sized conductors between the meter and disconnect is minor 3) The grounding/bonding conductors may have to be upgraded, but I'll consult an electrician for that (and all of the issues you've mentioned…I had not planned on proceeding without having a pro review my plans). I really just wanted to make sure I was on the right track re: replacing the meter/disconnect box with a larger disconnect (200 amps), then have a 150 amp breaker for the main subpanel already located in the house. I would then have additional room in the new meter/disconnect box to add circuits as needed
Best Answer
You can't just throw in a bigger breaker, and expect it to work the way you want.
First of all, you're going to have to have the utility install conductors sized appropriately for 200 ampere service. Depending on how the building is wired, you'll also have to upgrade the conductors that run from the service drop to the meter (this might be handled by the utility, depending on how the building is wired). Next, you're going to have to upgrade the conductors that run between the meter and the disconnect (likely handled by installing the new panel pictured). Finally, you may have to upgrade some of your grounding and bonding conductors, as they are typically sized based on the size of the service.
Once all that's done, then you can likely proceed as you've described. However, you're going to have to evaluate how the system is grounded. The service neutral will have to be bonded in the new panel, where the 200 amp disconnect lives. Then you'll have to feed the existing panel (now a secondary panel), with a 4 wire feeder (hot, hot, neutral, ground). You'll also have to isolate the grounded (neutral) bar in the existing panel, if it's not already.
Long story short, this is not a simple job. There are a lot of subtle details, that can easily be missed by a DIYer. I would recommend having an Electrician at least help you plan the project, and inspect the completed work.