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1st panel after meter: enter image description here

2nd panel fed by main panel on 100A breaker (Federal Pacific Stab Lok split bus panel): enter image description here

Meter: enter image description here

Service: enter image description here

(Armand annotation of what is what): enter image description here

The 2nd panel is original to the home and was at one point the first panel after the meter. More recently, the exterior panel was added for additional circuits. This work was done prior to my ownership so I’m not sure of the reasoning behind the approach.

There is no grounding conductor running from the 2nd panel to 1st panel. Additionally, the 2nd panel has neutrals and grounds bonded together.

My goal is to remove the dangerous Federal Pacific panel and replace it with a new panel.

My question are:

  1. Was this more recent, exterior service work a reasonable decision on the previous homeowner’s part, and is it code-compliant? I ask this because I would assume that simply replacing the original main panel with a more spacious new one would have made more sense. If this work was code compliant AND inspected then wouldn’t there have been a main disconnect required on the first panel? I’m under the impression that any kind of modification to the existing wiring of the 2nd panel would have not been acceptable by current code so it was left untouched (except for the feeder wires).

  2. What would you technically call this configuration? Two main panels?

  3. Which panel would be considered the first point of disconnect in this system?

  4. If I replaced the 2nd panel, would I wire it as a standard subpanel with grounds and neutrals separated (I would install an appropriately gauged grounding conductor back to the main panel?

Some things to note:

  • 2nd panel’s current position is a code violation (inside the kitchen with cabinets interrupting its clearance area). I’m guessing it was left alone because relocating it would have cost a lot more.

I plan to have this work permitted and performed by someone licensed, but I would like to know exactly what I’m dealing with before I take the next step.

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  • Can you post a picture of the meter box? There should be a breaker or a disconnect there, which would make both of those panels subs.
    – crip659
    Apr 15, 2023 at 19:47
  • I just edited them in, thanks
    – Ian C
    Apr 15, 2023 at 20:04
  • 1
    Looks like your Grounding Electrode Conductor is running up the wall to the meter box; is it connected to that box and/or any of the panel boxes?
    – Armand
    Apr 15, 2023 at 22:36
  • Is the first panel there in the photo of the meter? That is, in the first panel photo, are the wires coming down from the top coming from the meter? Or is the power from the meter coming in the botton left and landing on the 100A breaker? Also what is the size of the service, am I correct to guess 125A? Apr 15, 2023 at 22:38
  • @Armand that "rule of six, with sum of breakers exceeding service size" was banned a long time before NEC 2020. Apr 15, 2023 at 22:39

1 Answer 1

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That 50A Murray breaker doesn't belong there. Replace with an Eaton BR250.

  1. Was this more recent, exterior service work a reasonable decision on the previous homeowner’s part, and is it code-compliant? I ask this because I would assume that simply replacing the original main panel with a more spacious new one would have made more sense. If this work was code compliant AND inspected then wouldn’t there have been a main disconnect required on the first panel?

You're familiar with how a split bus panel works - up to 6 breakers that constitute the "main breaker" and they can add up to more than the service size; the only thing that makes this safe is the service Load Calculation. (and that safety is promptly voided the day you add another load without re-doing the Load Calc).

Well, this outside panel was installed using the same old "Rule of Six, and oversubscribe the service based on a Load Calculation we pinky-promise that we did". So yes. You're not "seeing things" :)

However that panel, the Eaton BR1224L125R, fell out of Eaton's catalog sometime prior to 2017. So it's not that recent. I don't recall the date oversubscribing the Rule of Six went out, but possibly it was leeeeeegal when done? Bad practice in any case, and serious penny-hoarding by the installer.

The outside panel is easily corrected.

From the wire size it looks like 125A service. Okey dokey: install a 125A breaker in the top left of that panel. Call the power company and say "we need a meter pull to replace the main breaker". They usually don't demand the formalities of permit and inspection for that. And they often do it remotely using the smart meter. Then break the seal, pull the meter and run #2 copper or 1/0 aluminum* from your side of the meter down to that 125A breaker. (the old wires won't reach). Torque everything to spec with a torque wrench.

Add a "tie down kit" to the breaker. Add panel labeling "Main Disconnect" right above that breaker. And you're done. Now you have a 125A main breaker for the whole house, and any worries of oversubscription are GONE. Good riddance.

If I'm incorrect and it's 100A service, things are easier. You remove the panel 2 feeder and set it aside, then you still replace the meter run except you go to that existing 100A breaker. Once that's done, the main lugs are free and you place the panel 2 feeder on the main lugs. So you're running the whole panel backwards but now you have 1 main breaker. Again the tie-down kit needs to be added.

Wait, if you have a 125A breaker could you do the same trick and feed the FPE sub from the main lugs? Yes, if the FPE sub is rated for 125A (probably) and the wires to it are rated for 105A (maybe). *


* This being service wire, it benefits from an 83% favorable derate from 310.15(B)(7) aka 310.12. So 125A service only needs 104A wire. If your service is 150A, then either make do with 125A or replace the outside panel with a 150A "main breaker" panel (ugh, that would be a pain because a main-breaker panel will be taller, and conduit would have to be reworked since it can only side-enter an outdoor-rated panel at the bottom.)

  1. What would you technically call this configuration? Two main panels?

You have a "Rule of Six" outdoor main panel which has been oversubscribed. Then you have a 3-wire feed (banned in 1999 or 2008) to an indoor subpanel which was a former "Rule of Six" main panel, which has a split bus.

A split bus makes literally zero sense on a subpanel, so most likely that panel is configured to be ONLY service equipment, with no ability to isolate neutral from ground. (plus, back when Federal Pacific was making their fire-starters, separating neutral and ground in subpanels wasn't yet a thing.) So they probably didn't separate neutral and ground owing to inability.

By the way, I notice a "Challenger" breaker in there; amusing, since Challenger is also notorious for faulty breakers. By the way, look straight above the Challenger breaker. See the burned up terminal? That's what makes FPE panels so dangerous - that was nearly a house fire. That's why there's no breaker there, and probably why they installed the outdoor panel.

  1. Which panel would be considered the first point of disconnect in this system?

The first thing past the meter. It's the Eaton panel and all the breakers in it are the main disconnet. There can be no more than 6 hand throws.

  1. If I replaced the 2nd panel, would I wire it as a standard subpanel with grounds and neutrals separated (I would install an appropriately gauged grounding conductor back to the main panel?

Yes, you are obliged to do that since it's new work.

Maybe not repeat the last guy's repeated mistake and don't get a panel that's barely big enough. Breaker spaces are CHEAP and I like to finish projects with half the spaces unused.

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  • Harper, I really appreciate your response. Thanks for explaining everything so well.
    – Ian C
    Apr 17, 2023 at 12:23

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