Splitting 320amp service to two 200amp panels with the meter base 200ft from the house

Question

I am installing a 320 amp service on my new house in Lewis County, Washington and am a little confused as far as how to split the service.

I have my meter base set on a rack 200ft from the house because that is as far as PUD would go without adding a transformer. I have 3" schedule 40 coming from the meter base to the house with 500kcmil/500kcmil/350kcmil in it right now.

My questions:

1. Am I required to have my 2/200amp disconnects installed at the meter base?
2. If so then do I need to run new conductors to the house or is there a way to split the service at the house instead?
3. If so then what do I use to do so and to downsize to something that the lugs on my disconnects and panels will accept?

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Edit... I need to clarify my situation so that I can ensure getting proper and complete answers which so far you have been excellent about giving. This is a house that I have been building for my family, 100% by myself (ok I sub contracted the gutters).

As far as the equipment purchased so far, it was on a recommendation from the engineer at the power company that was fairly vague (regarding the meter base and disconnects and the 400+ feet of 3" schedule 40 that I had to install from the nearest available transformer to where pud was willing to put the meter and then to my house from there)... And then some brief information from the inspector when I called him out to approve backfilling the trench regarding the choice of wire.

Obviously needed to be asking more and different questions when he was here but live and learn. So anyhow this is actually a 320amp service (residential 400 I am told) that is necessary due to an on demand water heater for my radiant heat that requires 100amps itself (3/40 amp breakers). So what I have is as follows:

a Eaton cooper b line meter base catalog no 324n and 2 eaton Eccvh200r disconnects as well as 2 standard 200amp house panels.

Answer 1

What you may not know is Washington is on NEC 2020, which changes the rules for meter pans and disconnects. The industry has responded with affordable products that largely comply.

Keep in mind that when I say "disconnect", I mean "main breaker". It is simply not affordable to have a separate disconnect from a main breaker, so the main breaker is used as the disconnect.

Even if they were separate, the main breaker would have to be immediately after the disconnect, because you can't have a long run of non-breaker-protected cable waiting for a nail hit.

Prepare for the possibility that you bought the wrong meter base. It may be more expensive to "double down" on the wrong meter base than to junk it and get the right one.

You need disconnect switch(es) at the meter.

The most affordable way to do that is a unit called a "Meter-Main", which places both the meter and the main breaker(s) in a single unit.

Depending on how you read it, Code says you need either 2 disconnects or even 1 master disconnect at the meter. You need to talk to your AHJ (permit issuing authority), as 400A disconnects are not affordable, so most AHJs are authorizing dual 200A disconnects.

Really, the bottom-line is what the local amendments are and what AHJs are allowing, given that following the letter of NEC 2020 NEC 2020 on 400A services means very pricey equipment right now. As such, this is a conversation that you need to have with your AHJ, because only they can tell you which affordable options (if any) are available to you.

As for the equipment already installed, somebody specced that. The person who did either knows something we do not... or they don't and should be liable for any mistakes. I would stop taking their advice unless it aligns with what your AHJ tells you.

Answer 2

Your problem #1: a ranch panel can't feed 400A to the house

Your primary problem is that a 2x200A "ranch panel" configuration can't feed 400A to your house without violating either NEC 225.30 on the number of feeders to a building or NEC 240.8 regarding circuit breakers in parallel. Instead, you'll need to pony up for a 400A, single-disconnect meter-main device; fortunately, since you're in Washington State, we can make a fairly reasonable assumption that your PUD permits EUSERC-compliant meter-mains, which means we don't have to worry about them being particularly picky.

Surveying the field of single-disconnect, 400A meter-mains/meter-panel combinations leads one to Siemens equipment as the least-cost option here, and with that, the MM0202B1400SCS (with a TA2J6500 lug kit) is what fits best into your application. Once you reach the house, you'll still need some form of disconnect there, though, and this can be handled most cleanly by using a non-fused safety switch as the disconnecting means. Once again, Siemens comes through as the least-cost option with the HNF365RA switch when combined with a HN656A neutral kit and HG656A grounding kit. The switch can then feed two 200A main breaker subpanels using 250kcmil conductors in conduit and the 10' feeder tap rules.

Of course, if you have loads outside the house to feed, this gives you more options: limiting the house to 200A lets you use any old "ranch panel" that complies with NEC 2020, such as the Siemens MK0402L1400SCS, while if you need to provide 400A to the house while feeding other loads, a MC2442B1400SDS can do the job, but you'd need to use some 4/0 wire, a pair of ECLK2225 sub-feed lug kits, and a MPDB67423 power distribution block to connect your 500kcmil feeder to the panel in this case.

Your problem #2: that 500kcmil feeder is a size too small for 400A

Your second problem is that the wires you put in are a size too small. Fortunately, that's fixable since you ran it all in conduit. Simply pull the 500kcmil out and replace it with 3x600kcmil Al XHHW-2 with a 1/0 Al XHHW-2 ground. (The local can-pak or scrapyard should be able to accept the old wire if you don't have a use for it, by the way.) If you want to keep the wire in place, the Siemens single-breaker 400A disconnects use industrial-style molded-case breakers that can be "dialed down" to 350A, so that's an option as well.

Your problem #3: putting the disconnects at the house won't work either

Your third and final problem is that your PUD's metering requirements specify that there needs to be a disconnect no more than 15' from the meter. This means that if you don't want to put a meter-main at the pole, you need to install a 400A disconnect (safety switch, most likely) at the pole to serve as that utility required disconnecting means. While it doesn't have to be fused, and Code will let you treat it as a meter disconnect, effectively, instead of as service equipment, it still makes the trough option you're proposing not nearly as attractive as it would be otherwise.

Answer 3

Another example of Harpers double 200A meter-base. Since the 400A disconnects are SUPER expensive and difficult to find (and they may not be on PUDs list of approved equipment for residential installs!) Biggest advantage of this is that your house panel can be fed from this with its existing panel which becomes a sub panel (you will need to separate grounds from common and possibly run a ground rod at the house)

If both feeds are traveling to the house, possibly in the same 3" conduit, be aware of derating requirements for each conductor for running multiple together in a single conduit. Harper can help with discussion about properly grounding these two house panels and separating the neutrals from ground at those panels.