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I've been searching online for a NEMA 3R enclosure to act as a combiner for two 40 Amp, 240v circuits coming out of two solar inverters. Total combined amperage is 80 Amps. The AHJ is going to be inspecting this box to make sure that there is no way to take any power off this box prior to the power meter socket, so I have been looking for an enclosure that can accept the two inputs (6 wires) with a single 80A, 240V ouput. I already have a 3 wire visual disconnect device (VDD) Square D DU323RB. While my AHJ appears to allow the VDD to act as a combiner, the VDD I bought doesn't have the capability to act as a combiner. In essence, I'm asking for help with my Google search to find this elusive box. I think this might work, but I'm not sure: https://www.zoro.com/square-d-load-center-lug-125a-120240vac-1ph-qo112l125g/i/G0578426/

In my plan, the AHJ and Utility made me specify: COMBINER BOX 80 AMP, 240V DG LOAD CENTER SIZED FOR DG BREAKERS ONLY OR RENDERED UNABLE TO ACCEPT ADDITIONAL LOADS

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    Do you actually need individual disconnects for the inverters, or can they share a single disconnecting means, and if it's the latter, have you considered simply splicing the wires together inside the safety switch enclosure with Polaris connectors? – ThreePhaseEel Apr 23 at 1:26
  • That sounds like a good solution if it's allowed. – LookingBack Apr 23 at 2:31
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  • I think if you read it again, you'll find it's not a shopping question. – LookingBack Apr 23 at 19:18
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Splice it together in the safety switch

While Square D does not make a double-lug kit for their general-duty safety switches, what you can do is use a 14-4AWG, 3-port, insulated mechanical connector per-phase to splice the two incoming wires together with a short pigtail of 4AWG insulated copper that runs off to the lug on the switch for that phase. That way, everything's tucked neatly inside the disconnect enclosure; this does have the downside that you can't independently disconnect individual inverters from the utility service, but for a purely grid-tied small-scale solar setup, this isn't a big deal.

  • That is a great solution. – LookingBack Apr 23 at 19:20
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    As a followup, my AHJ did OK my plan change to use the insulated mechanical splices inside the VDD and in fact, the inspector also found it to be acceptable. – LookingBack Jul 23 at 2:25

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