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I am installing a 10 circuit reliance manual transfer switch. I need to install the ground to the ground bar and the neutral to the neutral bar. However, both grounds and neutrals are mixed in my panel (main panel). On top on this, there are no available spots on any bus in my panel.

Can I double up a few grounds in this panel so I don't have to add another bus? As I understand it, the neutrals cannot be doubled but the grounds can.

My Electrical Main Panel craftsman 030791 8000 watt generator

Reliance Pro/Tran 2 transfer panel

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  • What make and model is your generator, and can you post photos of the labels on the inside left and right of the panel enclosure? Also, is taking your transfer switch back and getting a different one in the cards? Commented Aug 29, 2021 at 1:00
  • The generator is a craftsman 030791 8000 watt generator. It is a brand new gift from my father in law. The transfer switch is a Reliance Pro/Tran 2. The MWBC is on H and the 15 amp circuit below, which I shut off and cannot find any plugs or lights or anything that it controls. Commented Aug 29, 2021 at 14:19
  • H when tripped will shut off a basement fridge but tripping the other half of the MWBC will not do anything to any outlets or lights that I can tell. Commented Aug 29, 2021 at 14:28
  • Yes, I could take the transfer switch back if that is what needs to happen. I am wondering if that absolutely needs to happen though. Could I set the MWBC into the transfer switch on the 240 volt AB slot with a handle tie? Commented Aug 29, 2021 at 14:47
  • @CameronMorissette In that case, I would find the other half of the MWBC by tracing the wires coming out of that same cable... and since the MWBC isn't even used, just get rid of it by placing both hot wires on the same screw of a 15A breaker. Now it's a simple circuit, and it is transfer switch friendly, and no need for a handle tie in the main panel OR the xfer switch. Commented Aug 29, 2021 at 20:46

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You need a different transfer switch

Not only does your current transfer switch require a degree of finagling to work with multi-wire branch circuits, it can't be used with your generator even when MWBCs aren't an issue! This is because "select circuit" transfer switches only have a single neutral connection lead and no neutral switching, but your generator has a bonded neutral (says so right on page 2 of the manual), so whenever you plug the generator in to your current switch, neutral currents will start flowing via the grounding system, creating a shock hazard.

As a result, you need to return your transfer switch and get one with a switched neutral. This keeps currents on the neutral from taking that hazardous detour via your generator's neutral-ground bond and grounding wires. The good news, though, is that Reliance does make a switching neutral transfer panel that's suitable for what you want to do, namely the XRK0303 from their Panel/Link X series.

Once you have the correct switch, you will have to make a bit of a design change in how you do things, as switched-neutral manual transfer panels are essentially subpanels with extra switching gizmos in them, and thus are wired up as you would for a subpanel. I'd enlarge the knockout hole you already popped out to 1¼" then run a nipple of that size to the matching KO on the new transfer panel; as long as it's less than 24" long, you don't have to worry about derates, and can use up to 60% of the total area for conductors. You can then run the feeder hots and neutral and the branch-circuit hots and neutrals together in that conduit, using individual THHN wires of the appropriate color and size.

As to your main breaker panel, you'll need a 30A, 2-pole QO breaker to feed the transfer switch and a PK18GTA or PK23GTA accessory ground bar so that you can free up some neutral bar space by moving grounding wires to the ground bar.

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  • Thanks for your expertise! I am wondering if an interlock system would work best for me? Do you see any issues with that approach? Commented Nov 1, 2021 at 13:38
  • @CameronMorissette -- interlock kits don't play nicely with switched-neutral generators (switching neutral circuit breakers are notoriously spotty in their availability, and breaker retention in non-standard positions also becomes an issue as many retention kits only work in certain spaces on the panels they're used with) Commented Nov 1, 2021 at 23:23
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Transfer switch: can't do it.

See the red wire at "H"? *It is half of a multi-wire branch circuit (MWBC) - 2 hots sharing a neutral. You cannot use this type of transfer switch with MWBCs, unless the transfer switch has both of them on a tied breaker (one intended for 240V).

I can't even see where the MWBC partner black wire even is. It might be G, except that's a 15A breaker - why would they be different?

Even worse, "H" is a circuit you want to hook up. You have to solve this puzzle, or not use a transfer switch, at least, not on "H".

Buddying grounds

Yes, read the panel labeling. It will tell you if you can double or triple ground wires onto screws. Expect "up to 3" but read it yourself.

The below advice obsoleted by learning your generator bonds neutral and ground. That requires kit that throws neutral between utility and generator. However generally speaking, if you had a generator that did isolate ground/neutral, and it's possible to get an interlock for your panel, that's a far more robust choice than these very hokey and overpriced transfer switches.

This may be a better fit for a generator interlock

Given the MWBC complications, the simplest solution is a generator interlock. It is more robust anyway - it plays well with MWBC, AFCI and GFCI, and lets you power any circuit in the panel and you get to choose "in real time".

The generator backfeeds a breaker ($16) in the upper right (you move a few breakers around, easy). The sliding plate interlock ($70-ish) makes sure the utility-main breaker and generator backfeed breaker can't both be on at the same time. Add appropriate wires to an inlet ($60) in a location of your choosing, and you're all set.

Only 4 wires to hook up instead of that octopus. The hard part is it takes some "leg work" to identify the correct interlock for your panel. I would call real electrical supply houses until you find a Square D dealer, they will know for sure given your panel model number. If they don't have one for you, aftermarket companies do.

Transfer switches sell quite well on Craigslist.

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  • Thank you for your expertise. You are saying that it is impossible to use this transfer switch at all? What if I don't want to power this MWBC with the generator? From what I can tell this circuit is only powering a basement fridge, but I could literally unplug the fridge and plug it into another outlet nearby that is not on a MWBC Commented Aug 29, 2021 at 14:24
  • I also added a photo of the transfer switch kit I purchased. It did come with handle ties for 240 volt circuits or MWBC. Commented Aug 29, 2021 at 14:28
  • @CameronMorissette What ThreePhaseEel says moots my advice about an interlock. Portable generators are intended for use in campsites, and require special kit to wire them into houses. That (expensive) Reliance xfer switch is NOT the right kit. They are intended for use with slab-mount Generacs and panels too obsolete to get generator interlocks. Commented Aug 29, 2021 at 20:37
  • But other than that, Mrs. Lincoln, yes, the handle ties/240V breaker you pictured could be used on the MWBC. Or you could just not put half the MWBC on generator. Or (code allowing) you could merge the MWBC halves onto a single 15A breaker, and switch that with the xfer switch. Commented Aug 29, 2021 at 20:43
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To answer your question YES you can double up grounds on a square D QO panel.

I would double up enough to provide the spaces you need this code compliant.

As you mentioned, Never double neutrals that would be a code violation.

I prefer the manual interlock kit from square D a back fed breaker in the top right hand position then you select the loads you want to run by manually turning off loads not wanted.

I have installed a couple dozen of the type of transfer switches you have they are expensive and work fine.

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