Do I need a new loadcenter?


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Old 05-18-20, 04:38 PM
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Do I need a new loadcenter?

I am installing a grid-tied solar system and this is the crap Challenger (named for the space shuttle) load center that came with my house. It's 125 amps single phase, so with the 120% rule I might make it work. Trouble is, it's loaded with tandem breakers that are even handle-tied. So the "General Lighting" "circuit" is 60 amps, and probably covers a god-awful assortment of 120 and 240 appliances.

Also, it's half width (7") in its form factor, and you cannot get larger taller versions of half-width load centers, if you can even get them at all.

I haven't worked with massive tied network circuit maps, but I assume it would impossible to untangle all of this. I'm assuming there isn't a safeway to un-handle-tie any of the circuits. And no, there's no wiring diagram for the house.

Should I bite the bullet and replace it with a new box? The only change I want to make is to add a dedicated circuit for my stereo (20 amps) which would always run off the battery/inverter.

As ever, thanks for your kind assistance!

 
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Old 05-18-20, 05:32 PM
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Should you replace the panel..... yes.
Question...... how do you plan do that if it's in recessed area like you have there ?
Your solar installer will also need access into that panel which he can't get now.
Are you changing the panel DIY or having it done ?

It looks every circuit in your panel is either a 240v circuit or a MWBC (multiwire branch circuit).
I've never seen a home completely wired in MWBC's.
You will always needs to use either tied handle breakers or two pole breakers.
The breaker(s) controlling a MWBC must disconnect both circuits.

You mentioned a grid tied system in an older post...... solar critical loads.
I replied to the stereo question back then. You'd need a separate solar system with charge controller and batteries. A grid tied system is dead when there is no utility power.
 
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Old 05-19-20, 05:46 PM
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So the "General Lighting" "circuit" is 60 amps
That is not 60 amps. You do not add up the handles. You have 4 - 15 amp circuits.
 
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Old 05-19-20, 05:56 PM
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Thanks so much, PJ! You're invaluable to people.

So here's what I have: a 12-slot box 125 amp box, single phase, flush mount exterior, filled to the top with skinnies, all of them handle-tied multi-circuit wired.

I want three circuits on the critical load board:

1. Refrigerator
2. Stereo
3. Lights in the bedroom

Given the MCW crap, I assume I am going to have to go into the attic and:

1. As I'm on a cement pad, drop wires down to each of the above three locations from the attic and install new receptacles, sealing off the old ones
2. Run these circuits back to a new subpanel located near the already-full CSED
3. Remove one tied breaker from the existing CSED (trash compactor) and make that the breaker for the subpanel)

Does that sound like (the best/a feasible) way to go?

I would swap out the 20 amp Trash Compactor dedicated circuit (and plate off the receptacle in the kitchen) and use that space in the loadcenter to accommodate the subpanel breaker. Trash current part of a 20+20 tandem, that is handle-tied to another 20+20, as in the photo. Is that doable?


I checked with Square D, for example, and they don't make CSED loadcenters with more than 8 spaces, nor will they accommodate smartmeters, of which I have one. I assume the other mfrs. are the same. So that would mean a subpanel.

If I want to run the stereo off the battery, do I have to shut off power to the rest of the house? I suspect so. the alternative would be to add a second dedicated circuit to the stereo, run that to the stereo, so it would have its own dedicated POCO circuit, and take it out of the MCW mess.

Sound right?



 
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Old 05-19-20, 06:00 PM
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Got it. I am calling an electrician in anyway, but wanted to know my options. That did not make sense to me at all. So they are using 12 gauge wire all the way to the back of the loadcenter, along with the "ground/neutral", and just braiding them together back there?


. didn't see how that would be possible, but Multi circuit wiring is a bit over my head.

Thank you!
 
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Old 05-21-20, 09:16 PM
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Understand MWBCs now, and solution

I have learned a ton about my 100% MWBC wired house since my original ignorant post.

Solution is to use a line side connection "tap" and new subpanel. If the dinky main box has space! :>}
 
 

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