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I am installing a sub panel for a kitchen remodel. I have an existing sub panel directly below where I plan to install the new sub panel. The existing sub panel is fed off the main breaker box with an aluminum 2-2-2-4 sheathed cable, with a 70 amp breaker.

I have an existing 6/3 cable feeding an electric range that does not have a separate ground wire, which comes from the main breaker box. Since I am going to replace the electric range with a propane range, I no longer need the 6/3 range feed.

Does it meet code if I run a ground to the existing sub panel, and use the 6/3 range feed to energize the kitchen sub panel? I have read that it meets code to run a separate ground to the main panel via a new path to bring the range feed to code, but I can find no such provision while connecting to the ground bar on the existing sub panel.

Thanks

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  • Is your 6-3 is really #6 with 3 insulated conductors? You might get away with it but I believe the code states on “existing” circuits.
    – Ed Beal
    Commented Apr 26, 2021 at 19:01
  • It is 3 # 6 copper insulated stranded wire in a plastic sheath. The neutral is not a #8.
    – JerryC2021
    Commented Apr 26, 2021 at 20:52

2 Answers 2

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No, when you retrofit a ground, you must source the retrofit ground from the same panel as the conductors come out of.

Further, such a groundless feed can be retrofitted for ground but it cannot be used in new work.

It sounds like the house was built with electric, and you went to a lot of trouble to convert to gas. This is often done "with a vengeance" because traditional electric ranges are so awful compared to gas. So your logic is "Why NOT burn the bridge and make it impossible to go back, since any sane person will stay gas since electric is so awful". One technology change is inductive ranges, which by all reports are turning out to be quite good.

Another tech trend is toward electrification. Given these sea changes, I would expect in 5-10 years a new homeowner may want to dispense with the propane altogether in favor of inductive range, extended range heat pump, etc. This may be helped along by incentives either from gov't or power company.

Therefore, given that the 6/3 "no ground" feeder is utterly useless as a subpanel feeder, and still useful to the next homebuyer for fitting an induction range (and thus, adds value to the home), my advice would be to leave it alone.

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I note your your existing subpanel has a 2-2-2-4 feeder going to it. That feeder is good for 90A (if the existing subpanel is). So I would simply "tee" off that existing feeder with additional 2-2-2-4 to the new kitchen subpanel. Now both old and new subpanel are sharing a 90A feeder. That's more than plenty for a gas kitchen.

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  • You are some what correct in that this house began with electricity. A Delco battery and generator. Then some time later a knob and tube system was installed. Other that the 220 v circuits, all of the 110 v circuits were still working off of the knob and tube when my familyand I saved in 20 years ago. As far as the propane, it was installed in the late 60's by my grandfather. About a year after moving in, I had a propane central furnace and central air installed. To give you better perspective, the house was built in 1917 by my great grandparents. Thanks for your reply.
    – JerryC2021
    Commented Apr 28, 2021 at 18:56
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If you have an existing sub that is not grounded and want to ground it.

The NEC article 250.130.C.4. Applies, The sub(s) each of them are a branch circuit from the main. Both branch circuits originate from the same panel board.

So yes if both subs are existing one has a grounding conductor and one is not a grounding conductor could be run from one to the other.

Your issue would be that it was for the oven not a sub, in my state an existing 3 wire connection can be moved up to 6’ without a permit required or a new 4 wire feeder required (redecorating). Is the 3 wire in good condition? Local code amendments to the NEC may allow it but I would do some checking to make sure.

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  • Thank you Ed for the follow-up answer.
    – JerryC2021
    Commented Apr 26, 2021 at 22:38
  • The new panel will not require me to move the Range feed wire. If I run a 6/3 with ground from the existing sub panel, I have to make room for the main breaker for the second panel. The breaker box I purchased is an Eaton 125 amp 8/16 circuit with no main breaker. I bought 5 of the Arc Fault/Ground Fault 20 amp breakers. My supplier suggested that I use a regular breaker for the refrigerator, due o the possibility it could cause a false trip and I would have spoiled food if it tripped when I was not at home.
    – JerryC2021
    Commented Apr 26, 2021 at 22:48
  • I agree with the standard breakers for refrigerators and freezers and my state allows that even where the NEC has no exemptions.
    – Ed Beal
    Commented Apr 26, 2021 at 23:25

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