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Long story short: Bought an old house and LADWP asked me to put in a new meter panel at the back of the house and convert the existing old (front) and very small panel to a sub. Both panels will be 200amp. LADWP will pull the underground wire to the new meter panel and it will have no other breakers except just the on/off switch.

Question: Is there a sub-feed lug kit suitable for me tee off dual 2/0 (main underground powerline and another line to the sub) in each of the two main lugs? Any advise would be appreciated!

Both panels are Siemens: Meter panel (Model# MC2442B1200ESV) and sub panel (Model# PN3048B1200C)

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  • Note that this is a perfect opportunity to replace the existing panel with one that has more space for breakers/circuits, giving yourself space for easy expansion in the future. You'll already have the electrician on site, they'll already be working with the supply side of the box; that's the majority of the labor cost already covered. Box is not expensive. New breakers may add up, but that's arguably preventative maintenance.
    – keshlam
    Sep 20, 2023 at 15:09

2 Answers 2

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Unless you have something going on you have not described, (such as adding a new sub-panel as well as the old main one as sub-panel) there's nothing to Tee here.

The new powerline comes into the meter and then line side of the main breaker. The output lugs of the main breaker connect to the bus bars in the new meter-main panel, and the feed-though lugs on its bus bars are (at this point in the description) unoccupied.

You describe running a set of wires to the old main panel turned sub-panel, which is one set of wires to go into those feed-though lugs. Not two. Your service wires are on the other end of the equipment, not joined to your feed-through lugs.

You can get a variety of connectors suitable to Tee 2/0 wires, but I'm seeing no need for what you have described.

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LAWDP and your inspector can tell you to use a meter-main, because that's a code requirement.

LADWP cannot tell you to use an "all-in-one" (meter + main + all your breakers)... that's just you being cheap, or the utility being cheap on your behalf e.g. "most builders prefer..." well of course they do.

That particular one is a dumb choice for you, because it provides what you don't need: 24 breaker spaces, yet ignores what you do need: "Thru Lugs" to carry the full 200A onward to your other panel.

In fact, no one should use an "all-in-one"

And the reason is the changes happening in California with V2X - Vehicle To Home/Grid/etc. Also, PowerWalls and other 21st century approaches to grid-down living. All of these things require inserting an isolation switch between your meter pan and the breakers that you want protected - including your solar if you want that to charge batteries during grid-down. (the main breaker can be on either side of this disconnect, but "utility side" is easier).

The problem with all-in-ones is they provide nowhere to insert that isolation switch. California, where all-in-ones are beloved by builders, is going to pay dearly for that.

Of course, V2X and home batteries are not great news for utilities, which is why we can expect them to "mislead and impede" to the greatest extent possible, e.g. recommending all-in-ones. That's why "a meter collar" doesn't work as a silver bullet for all-in-ones: the utility must approve meter collars, and why would they?

The ranch panel may help, though

This has (optional) meter, main breaker, 4-12 breaker spaces, and most importantly, "thru lugs" to carry 200A onward to another panel somewhere else.

In a PowerWall/V2X environment, everything in the Ranch panel will be on the wrong side of the isolation switch, so make sure everything out there is stuff that's unimportant during an outage, e.g. 2nd EV charge station, air conditioner, hot tub, etc.

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  • unimportant during an outage...air conditioner Really? If that outage is in the summer, or if the A/C is a heat pump then even in the winter that is really important. I know it is a huge load, but still. 2nd EV, clothes dryer, dishwasher, hot tub - plenty of things you can leave out. But HVAC is pretty important, particularly if that outage is due to rolling blackouts from summer overloads. Sep 20, 2023 at 4:56
  • Please. I grew up in a hot muggy state (90s in the summer), as a member of the upper middle class. We had a very charming 1950 home that was built without forced-air, so A/C retrofit was not practicable. (We could've done window units, but we never bothered, today with climate change we might've had one 10k BTU window unit just to take the edge off). We learned to live without it so it was no inconvenience, first rule being if a room's too hot, don't be there. When people have "always-A/C" they never learn to live without it. There's also this thing called "obesity" that seems related. Sep 20, 2023 at 19:25
  • When we had a several day outage from a derecho several years ago (after which the govt pushed the electric utility to do major upgrades, haven't had more than a few hours at a time out since then) survived cooking on gas, phones charged in cars, etc. But even sleeping in the basement was tough without air conditioning in Washington DC area in July. When I was a kid we didn't have ac in the car, we had 455 - 4 windows at 55mph. Times change. Sep 20, 2023 at 19:34

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