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So im in the middle of installing a mini split in my home and i was about to start the wiring but when i opened up my main panel i realized that i dont have any grounds anywhere.So i started doing my research online and i saw that maybe my grounds are bonded with my neutrals but i dont see a green bonding screw nor is there a stranded ground wire coming to it.I know the home is old so maybe they didnt add a ground to them back then.So do i just add a ground? or just leave the ground out and just put a cap on it

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  • Can you get us photos of the label on the inside of the panel's door (if present)? Also, where does the bare (greyish) wire from the lower large lug on the neutral bar lead to...? Apr 22, 2021 at 22:26

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You have an old "BX cable" installation. This was common 100 years ago they ran "flexible armored cable" in homes - quite often in conjunction with "knob and tube" wiring. There were NO separate "safety grounds" at the time. The panels DID NOT HAVE a separate "safety ground" bus panel. "Safety grounding" was SOMETIMES done at the meter panel, then a metal tube ran from the meter to the breaker box, supposedly providing a ground path, and then the supposedly grounded panel box itself provided a ground through the BX armor on the wires assuming the correct metal clamps were used on the jacket of the BX cable where it entered into the panel. Sometimes they would run a "ground" wire from the panel to a cold water pipe.

The CORRECT WAY to have electrical outlets in this setup was to have UNGROUNDED outlets WITHOUT a ground prong. Of course this would require using the "cheater" 3-into-2 with a dangling ground wire things everywhere. But at least the user plugging anything in would know the system was ungrounded and could either buy double-insulated appliances or take their chances.

"back in the day" people would sometimes drill holes in these panels and install a separate ground bus and ground wires assuming space existed in the breaker panel. Yours certainly does not have enough space for this IMHO. I personally would question if all those breakers in there would even trip at all they are so old. Plus you do NOT have a proper main disconnect breaker.

If this was mine I would demolish the main panel and buy a modern one with modern safety "smart" breakers in it. Your incoming cabling from the meter also looks like possibly a 100amp (or maybe lower) service and I would suspect the thing is already overloaded so demolish all that and replace with a proper modern feed from the meter. Those old 2 wire systems are safety hazards and at the least, doing it this way will give you some GFCI/AFCI protection and with an old wiring system like that, plus given the tampering it has likely suffered over the years, that would be the wise choice.

Look at it this way - you are already saving a ton of money installing your own mini-split, well I would rather be safe from electrocution in my own home than cool so take that savings and spend it on a main panel replacement. Yes I know you are looking for a quick answer here but there is none. There is NO safe way of "modifying" this installation to make it safer with ground wires and whatnot and the second you touch the panel like that you are required by law to follow code and there's no jurisdiction out there that would allow a panel like this to remain and meet code.

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    Retrofitting equipment grounding wires in NECland is possible to do safely, see NEC 250.130(C) for the details. Also, you've confused equipment grounding and system grounding here. You're right on the panel swap, at least, but that's needed not for grounding reasons, but because the querent has a Firey Piece of Equipment for a panel Apr 22, 2021 at 11:48
  • I knew the NEC allows it but I did not want to encourage some hack solution that would end up happening in THAT panel. As for confusing equipment grounding with system grounding, I tried in the answer to deliberately ignore the "maybe my grounds are bonded with my neutrals" statement since clearly that was leading into a ground discussion and I did not want to give the impression that it would be possible to modify THAT panel in any way to make it safe. That panel would have fallen under "Rule of 6" I believe for the lack of a main but that rule was deprecated ages ago. Apr 28, 2021 at 1:05
  • No, that panel is NOT a Rule of 6 panel either -- it uses a backfed main breaker in the top right two spaces. Apr 28, 2021 at 1:06
  • That doesn't appear to be a single unified main breaker it appears to be 2 individual breakers. That panel isn't likely what you would call a "split bus" panel but I don't see why it wouldn't fall under the 6 throw rule. I don't have a paid access to the NEC code book but all quotes I can find for NEC 230.71(A) speak only to the disconnects not the panel organization. Apr 28, 2021 at 1:21
  • FPE 2-pole breakers don't have a handle-tie, instead relying on the common trip mechanism for common shutoff Apr 28, 2021 at 1:49

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