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Couldn't find anything in the NEC 2017 that forbids it, but wanted to double check: Can multiple grounding electrode conductors (thick multi strand is the outside-ground-rod wire, thin single 6GA is the water pipe bond wire) be placed on the same lug (green) on the Square D QO main svc panel (QO142M200PCAFVP)?

I could put the waterpipe bond wire on one of the side ground bars, but if I don't have to, I want to leave it where it is.

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That lug can’t be double-tapped.

Large wires can generally never be double tapped.

Check the labeling on your panel for the list of sizes allowed for double or triple tapping on which lugs. Don’t expect wires larger than #10 to be permitted.

You must obey panel labeling and instructions NEC 110.3B.

If your wire can’t reach, feel free to use the vacant screw hole just to the right of the main lugs to mount a lug e.g. a double lug. Electrical supply houses stock those. It is probably a #10-32 screw.

You can also drill your own holes, but must be -32 thread pitch or finer. Nobody ever got fired for using 10-32.

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  • The part of the comment that states that this lug is for neutral and not for ground directly contradicts the commentary that was made here about this lug: diy.stackexchange.com/questions/200135 Does it really make sense to land grounds on the groundbar and not the N-G strap? Could you please provide where it says this lug is for neutrals and not grounds, if it's a bonded (green screw top right) panel? – sil80 Aug 3 '20 at 18:39
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    The difference grounding vs grounded. Grounded or neutral can never be double tapped unless MFG instructions provide instructions to do it. Grounding or green/bare ground can be up to 3 is the most I have seen the panel cart usually lists 2-3 for 14 & 12 awg conductors if it’s not listed the limit is 1. – Ed Beal Aug 3 '20 at 19:18
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    @sil80 -- grounding electrode conductors (the "system ground conductors" you're talking about) are closer in nature to equipment grounding conductors than to neutral conductors, but large lugs aren't rated for double-tapping to begin with, making this moot. (They're also too large to permit double-tapping even on bars that permit it.) – ThreePhaseEel Aug 3 '20 at 22:28
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    @sil80 -- what I was saying there, BTW, is that the lug in question can be used for neutrals, not that it is for neutrals only. – ThreePhaseEel Aug 3 '20 at 22:32
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    @Harper-ReinstateMonica -- I would probably rather see an Ilsco GTA series or equivalent tap lug used to join the water pipe bond conductor to the ground rod conductor than an extra foot lug wedged onto the panel. (The continuous-length requirements of 250.64(C) don't apply to water pipe/structural steel bonding jumpers.) – ThreePhaseEel Aug 3 '20 at 22:35

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