I have a 200 amp main service at a property I recently bought. It’s feeding a 175 amp breaker panel at a small home and garage. I was wondering if it was okay to run another 175-200 amp panel from the main panel to power a manufactured home by possibly getting a subfeed lug kit or would I have to get a 400 amp service upgrade?

  • Another option is to get a second 200 Amp service separate to the first service, leaving each home separate. This may help with billing.
    – Criggie
    Mar 18 at 20:45
  • 2
    @Criggie It can help with the billing if the idea is that the new home may later get rented or sold (depending on zoning) as opposed to just being used by extended family. On the other hand, each separate service normally comes with a bunch of monthly fees that end up being doubled if you have 2 x 200A instead of 1 x 400A. Mar 19 at 1:32

1 Answer 1


You need to do an NEC Load Calculation. This takes into account:

  • Size of each building
  • HVAC (larger of H or AC)
  • Required dedicated circuits (kitchen, bathrooms)
  • Cooking equipment (gets complicated)
  • Water heater (if electric)
  • Washer/dryer

and a bunch of other things. It results in a number that determines the service required for your building(s) or for a specific subpanel.

Run the numbers for your existing property. Then run the numbers for your manufactured home. If the total of the two is less than 200A, you're all set. If it is substantially more then you will probably have to upgrade, but there are often things that can be done to either make one (or both) of the buildings have a much lower load calculation or to adjust usage on demand to keep the totals under a set limit.

Note that a Load Calculation is NOT:

  • Add up all the breakers - that will be way too high
  • Look at your electric bill - that will often be much lower and you don't know when you will have peak usage. And it doesn't help at all for the new home.
  • Guessing. Sorry, can't do that.

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