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I have a 100A old-style circuit breaker main (~1970, 2 conductor & ground) in the basement.

I want to upgrade the circuits in the garage to allow for solar panels and PEV cars, so my thought was to install a new 200A service main outside the basement, turning the old main into a subpanel, and running a new 100-150A subpanel to the garage.

So the garage components, being new would need to conform to NEC 2017 code.

The question is about the old 100 main that would then become a subpanel. Since it wouldn't conform to newer codes, would I need to replace / upgrade it as well to separate neutral and ground. See attached picture below. Neutral and grounds are together on the same bar, and a braided bare copper wire bonds the box to the neutral bar at the inbound conduit. Also there is no copper grounding rod electrode outside at my house.

My gut tells me I have to upgrade this box to new code, but I thought I'd ask.

Old Entrance Panel

Thanks, Brian

Edit. Adding second picture of upper left focus. enter image description here

All responses very helpful, hard to select just one.

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  • Forgot to add, I live in Eagan Minnesota (suburb of MSP/STP)
    – bfoddy
    Oct 1, 2018 at 5:03
  • You seem to be connecting "old equipment" to "not compliant with current codes". False connection. Code compliance has nothing to do with age and there's nothing wrong with a BR panel.
    – Harper - Reinstate Monica
    Oct 1, 2018 at 5:37
  • Is the feed to this panel in some sort of metal conduit, nonmetallic conduit, or a cable?
    – ThreePhaseEel
    Oct 1, 2018 at 11:48
  • This box is connected by metal conduit to the meter and from there arial lines to the transformer.
    – bfoddy
    Oct 1, 2018 at 16:28
  • @bfoddy -- where does the white wire exiting the photo at the bottom left lead?
    – ThreePhaseEel
    Oct 1, 2018 at 22:41

3 Answers 3

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You'll need to do a few things while you're in here

There are a couple of points that need to be addressed to bring this panel up to where it needs to be for the upgrade.

First off, you'll need to convert this panel to a proper subpanel -- the box bonding jumper will need to be removed, and the grounds moved to a new ground bar (an Eaton GBK21 should suffice given the size of the enclosure).

Second, you'll need to fix the alien breaker problem in your panel -- the two bottom-right breakers don't belong in your panel at all as they're the wrong make/model for it (they're Gould QP breakers in a Bryant/Westinghouse BR panel). The proper replacements are a BR250 and a BR120, and should be available just about anywhere that has Eaton breakers available.

Third, you'll want to use some white electrical tape to mark the fat neutral wire going up into the top right conduit knockout as a neutral. Simply wrapping the wire in the correct color tape for say, 6" or so will do the trick.

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  • Your comment about the black neutral takes a very keen eye, I didn't even notice it until I zoomed in the original picture about 10 times on my phone. There is another strange #2 white ground wire looping down and up the left side. It isn't paired with anything else I can see. I've noted there isn't a grounding electrode outside I can find, I bet that is grounding somewhere to a pipe or something.
    – bfoddy
    Oct 2, 2018 at 4:02
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    @bfoddy I was wondering about that wire. Make sure it isn't being used as neutral for a 240V circuit sourced from somewhere else. Noting the white wire leaves the panel not in conduit, which suggests it may be the work of honey badgers. Code is Code for good reasons, but honey badgers don't care.
    – Harper - Reinstate Monica
    Oct 2, 2018 at 17:30
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First your existing panel falls under the NEC it was built under, whatever it was, in 1970 in your area. This is known as the grandfather clause. So it is fine since you are not trying to add to it, just upgrade your service. Now everything you are installing new has to fall under the code in enforcement in your area today.

So your intent as you have stated is fine. The only thing that I would change in the existing panel would be the grounding. Since you are installing a new 200A main the grounding process must start there. So ground the new panel per the current NEC and remove the bonding screw or jumper from your sub-panel. Install an grounding bus in the sub-panel and move your ground (bare wires) to the new grounding bus. I can't give you the exact details of how because of lack of information.

Other than that I would say you are good to go. Good luck and stay safe.

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    I agree isolation of ground and neutral wood be needed it looks like your conduit is bonded to the box so that should be your ground. The panel itself is fine. I'm my area since your panel is not being changed (other than the grounding) the local AHJ here would only require the neutral isolation.
    – Ed Beal
    Oct 1, 2018 at 13:16
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The panel is fine for new work. It's a BR panel, sold today at Home Depot branded as Eaton. You will need to buy an accessory ground bar (note screw holes on left side of panel awaiting a ground bar) and remove the neutral-ground jumper from the neutral bar. Also those bogus breakers in the lower right need to be replaced by proper BR breakers. Those will cost you, are you sitting down? $14.

Most panels use 1" breakers and a relatively similar way of hooking on the tail. However the jaw and busbar are different and not physically compatible, they will snap in but with a weird insertion force, and will later burn up under load.

However the ground bar won't get a lot of business. From the mirthful wire colors in use, it is clear that much of your wiring is THHN inside metallic conduit. In those cases, the good metal conduit literally is the ground wire, and no ground wire is present or needed. This can really freak you out if you're seeing it for the first time!

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  • Yes, much of the original wiring uses metallic conduit and frequently functions as the ground. No I don't like it, but not much I can do.
    – bfoddy
    Oct 2, 2018 at 3:55
  • @bfoddy embrace it. Do like it. Conduit is a vastly superior system. As long as the fittings are tight and not horribly corroded, conduit grounding can carry vastly more fault current than those thin little #12 ground wires in Romex, which makes the grounding system more responsive i.e. You are more certain to get instant breaker trips when needed. And less wire, cleaner panel, easier to work with... there is basically no downside except the grunt work of fitting conduit in the first place. Make the most of it. It's a Good Thing.
    – Harper - Reinstate Monica
    Oct 2, 2018 at 17:26

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