Dedicated Combiner Panels: AC-Coupled & Output

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tomahawk44

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Chicago, IL
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Installer
Is there any reason particular reason why a breaker type panel (instead of a main lug type) wouldn't be allowed for dedicated combiner panels such as for AC-Coupling or Inverter output? (Other than the local building inspector whim?)

I just noticed it, but for EG4 diagrams sometimes don't explicitly state.


Some of the diagrams I come across for Sol-Ark I think specifically state Main Lug.
 
tomahawk44 said:
Is there any reason particular reason why a breaker type panel (instead of a main lug type) wouldn't be allowed for dedicated combiner panels such as for AC-Coupling or Inverter output? (Other than the local building inspector whim?)

I just noticed it, but for EG4 diagrams sometimes don't explicitly state.


Some of the diagrams I come across for Sol-Ark I think specifically state Main Lug.
Click to expand...
No reason at all, although the panel MCB would be redundant with the OCPD that is required at the other end of the conductors from the combiner to the point of interconnection.
 
In those diagrams EG4 seems to be thinking that where they have a combiner that combines off-grid outputs, a main breaker in the combiner protects the downstream conductors closest to the point of supply. Which is fine, but I think they could show a fused disconnect downstream of a main lug panel instead. Then again, I don't see why they have an unfused disconnect downstream of the combiner at all, that isn't required by the NEC, or even usually by utilities AFAIK.
 
Ok now I'm noting that in some of their diagrams they have three 40A off-grid inverter breakers feeding a 100A feeder. So options are either:
1) main breaker in panel to protect downstream feeder
2)size feeder at 120A as far as the next OCPD
3) follow the tap rules to the next OCPD, e.g. fused disco

In general, you can and should follow NEC rules on this, and worry a bit less about what manufacturers show.
 
But in answer to the OP's question, there is no reason why a main breaker would be disallowed in an AC combiner panel.
 
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