CYA Posted March 12, 2020 Report Share Posted March 12, 2020 I did an inspection this afternoon that I have questions about. The service line was a double #3 copper line. This seems to be a big issue to me but have not found anything in writing to hang my hat on. Thoughts are greatly appreciated. Quote Link to comment Share on other sites More sharing options...
Marc Posted March 12, 2020 Report Share Posted March 12, 2020 (edited) As far as I know, it's fine if all lugs are used within their listing. All conductors need to be in the same wireway so that the inductive forces cancel out, otherwise inductive heating could result. Conductor pairs need to be the same length so that currents are equally divided between them. Two #3s would work for a 200 amp service, not that I would do it. I never have and I'd try very hard not to ever do it that way. I would not write it just because the conductors are in pairs. Edited March 12, 2020 by Marc Quote Link to comment Share on other sites More sharing options...
Jim Katen Posted March 12, 2020 Report Share Posted March 12, 2020 3 hours ago, CYA said: I did an inspection this afternoon that I have questions about. The service line was a double #3 copper line. This seems to be a big issue to me but have not found anything in writing to hang my hat on. Thoughts are greatly appreciated. Parallel conductors are not a problem by themselves. But they're rarely, if ever, installed properly in a single-family home. If there's a problem with the installation, it will be with the details. For instance, I've never seen a 200-amp load center that features lugs listed for two conductors. Do you have pictures? Quote Link to comment Share on other sites More sharing options...
CYA Posted March 12, 2020 Author Report Share Posted March 12, 2020 Quote Link to comment Share on other sites More sharing options...
Jim Katen Posted March 12, 2020 Report Share Posted March 12, 2020 <strike>Those lugs are not listed for two conductors. The installation is wrong.</strike> Edit: I should probably say that the likelihood of those lugs being listed for two conductors is remote in the extreme. Check the panel schematic to be sure. The wiring mess on the neutral terminal bar makes me suspect that the installer was not entirely competent. 2 Quote Link to comment Share on other sites More sharing options...
mtwitty Posted May 14, 2020 Report Share Posted May 14, 2020 #3 size are not allowed to be used in parallel. 1/0 AWG in the minimum size allowed for parallel feeds, per 310.10(H). For that reason alone, it's wrong. 1 Quote Link to comment Share on other sites More sharing options...
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