I'm going to erect a power pedestal on my lot that will initially allow me to power my RV (50 amp). I will locate this pedestal so that when the barn/shop is built it can be fastened directly to the side of the new structure. I'm trying to determine if I can use the 400 amp Siemens MC0816B1400RLTM Service panel to send 200 amps to my house and 200 amps to my barn/shop.

The configuration has one place for a future 200 amp breaker that I would use for the house sub panel - great. The lower portion shows a QN2200RH main breaker & accommodation for 8/16 circuits. At first I would install a 70 amp breaker on this buss to power a RV Hookup box with a 50 & 20 amp outlet.

Could I then remove the 70 amp breaker (and RV hookup box) and use the feed thru lugs at the bottom of the bus to route the entire 200 amps to the 200 amp sub panel in my barn/shop? If this is a legal wiring configuration it would result in the least amount of redundant hardware. On my last house I used a MILBANK U4835-X-2/200-BL service panel (400 amp to two 200 amp main breakers), which is a great product.

The difference here is the need for a RV hookup for up to two years before the house & barn/shop are built. And using the MILBANK is more expensive (2X) to start with and requires an additional subpanel enclosure to step down the amperage to the 70 amp RV hookup box.

1 Answer 1


Yeah, that's legitimate and normal use of that particular type of panel.

It has two sets of lugs meant to feed to a 200A panel each. One is on the bottom of the 8-space mini panel, and the other is on the output of the optional second breaker.

You can come off either one with 200A wire (250 kcmil aluminum, since 310.15(B)(7) doesn't apply to part of a service) and go to a 200A sub-panel elsewhere. In fact, you can split it and go to more than one. (however the wire must be 200A rated if you do).

Now, you seem to have a misconception that the sum of the breaker handles can't exceed the main trip. (70A to a 50+20A subpanel; removing 70A sub to use the 200A feed). That actually isn't true. Panel overloading is prevented two ways: #1 the breakers, obviously. #2 a Load Calculation must be done on the installation and each subpanel, which earnestly tries to peg a number on the power you actually intend to use. The Load Calculation dictates the minimum service or feeder size.

Load Calc's are a little complicated, but let's hit up a few highlights.

  • Kitchen and bathroom receptacle circuits are allocated 1500 VA each. (which coarsely means watts).
  • An allocation of 3 VA per square foot covers all other "general use" receptacle and lighting loads in a dwelling.
  • Ranges/ovens have a complicated little bit of math to reflect actual, realistic load while cooking Thanksgiving dinner.

You need to break out the sharp pencil for a Load Calculation, and you have to do that on a per-panel basis. But an RV stand has been done FOR you, any RV stand containing 50A, 30A and 20A receptacles can be allocated at 12 KVA (50A). "That was easy"

(and for multiple RV stands, they give favorable derates, for instance 2 RV stands calculate to 90A. That's handy because affordable #2 aluminum is 90A. Actually I would use that on your single RV stand because it's way cheaper than #6Cu. At these large sizes, aluminum is proven reliable.)

So yes, you can do that, and you can leave the 70A(?) breaker to the RV stand in place after you do. That's what this type of farm/ranch panel is all about.

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