EricS Posted March 21, 2011 Report Share Posted March 21, 2011 Saw a sub panel back fed by a 100amp breaker in the main. The common from the sub and common from the main where clamped togther in the main panel. Is this okay? I ask because we came across serveral outlets powerd by the sub that were not reading a ground. Could the two commons being together cause a false read? Thanks Eric Quote Link to comment Share on other sites More sharing options...
hausdok Posted March 21, 2011 Report Share Posted March 21, 2011 When you refer to "commons" are you referring to the equipment-grounding conductors ("grounds" - bare or green wires) or to the grounded conductors ("neutrals" - white wires)? ONE TEAM - ONE FIGHT!!! Mike Quote Link to comment Share on other sites More sharing options...
EricS Posted March 21, 2011 Author Report Share Posted March 21, 2011 The neutral white wires Quote Link to comment Share on other sites More sharing options...
hausdok Posted March 21, 2011 Report Share Posted March 21, 2011 OK, Now I think I'm forming a picture; the grounded (neutral) conductor from the sub-panel is secured under the same lug in the main panel as the grounded conductor from the service entrance. As far as I know, it's not OK to do that. First, a lug has to be rated for two conductors and second there is rule that grounded conductors will each have their own little seat on the bus. There should have been another lug somewhere on the neutral bus in that main panel to which the grounded conductor from the sub-panel feeder can be attached. ONE TEAM - ONE FIGHT!!! Mike Quote Link to comment Share on other sites More sharing options...
EricS Posted March 21, 2011 Author Report Share Posted March 21, 2011 Thanks Mike Quote Link to comment Share on other sites More sharing options...
John Kogel Posted March 22, 2011 Report Share Posted March 22, 2011 The grounding or lack of it should not be related to the doubled neutrals except for one thing - both are signs of amateur attempts at wiring. I'd call for a qualified electrician to inspect the whole setup. Quote Link to comment Share on other sites More sharing options...
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