randynavarro Posted December 10, 2009 Report Share Posted December 10, 2009 I think this might be really simple, but something isn't sitting quite right in my head. The picture shows a pair of wires (240v) exiting the main panel via EMT. Click to Enlarge 25.18 KB Outside showing the EMT Click to Enlarge 37.26 KB Here's the wiring at the disconnect. Click to Enlarge 43.21 KB Is it all ok? Link to comment Share on other sites More sharing options...
Chad Fabry Posted December 10, 2009 Report Share Posted December 10, 2009 Is the unit chassis bonded to ground? Link to comment Share on other sites More sharing options...
randynavarro Posted December 10, 2009 Author Report Share Posted December 10, 2009 Is the unit chassis bonded to ground? I can't say 100%. I know the green grounding wire in that 3rd pic. runs out of the disconnect box, thru the flex conduit (plastic - I forget the name of it right now), and into the A/C housing. I'm assuming it's bonded inside the A/C housing. . . Click to Enlarge 78.04 KB Does anyone check wiring connections inside the A/C housing? Link to comment Share on other sites More sharing options...
Terence McCann Posted December 10, 2009 Report Share Posted December 10, 2009 thru the flex conduit (plastic - I forget the name of it right now), Are you thinking of Sealtight? Where did they pickup the ground from Randy? Link to comment Share on other sites More sharing options...
randynavarro Posted December 10, 2009 Author Report Share Posted December 10, 2009 Where did they pickup the ground from Randy? Not sure I follow the question. . . .I thought Chad asked sort of the same question. Maybe I'm confused. Grounding path from A/C unit back to main panel is via green grounding wire back to main panel via the EMT. Link to comment Share on other sites More sharing options...
Terence McCann Posted December 11, 2009 Report Share Posted December 11, 2009 Where did they pickup the ground from Randy? Not sure I follow the question. . . .I thought Chad asked sort of the same question. Maybe I'm confused. Grounding path from A/C unit back to main panel is via green grounding wire back to main panel via the EMT. I only see two wires leaving in your first picture. Link to comment Share on other sites More sharing options...
Jeff Remas Posted December 11, 2009 Report Share Posted December 11, 2009 The emt is the grounding conductor, the green wire is the ground for the equipment that the disco serves. Link to comment Share on other sites More sharing options...
randynavarro Posted December 11, 2009 Author Report Share Posted December 11, 2009 The emt is the grounding conductor, the green wire is the ground for the equipment that the disco serves. Yea, that's what I said . . . maybe sorta. So it's all ok? Link to comment Share on other sites More sharing options...
Carson2006 Posted December 11, 2009 Report Share Posted December 11, 2009 Yup! Seems like "someone" used the EMT as an equipment grounding conductor. Ok for the most part, however, notice the paint under the connector in the main panel. Too easy to make it a better, safer installation by running a EG conductor back to the main panel's grounding bus. Plus, not a good idea to use conduit as an EG when there are concentric/ecentric K.O.s. Believe it violates NEC; 90% sure. Link to comment Share on other sites More sharing options...
Jim Katen Posted December 11, 2009 Report Share Posted December 11, 2009 Yup! Seems like "someone" used the EMT as an equipment grounding conductor. Ok for the most part, however, notice the paint under the connector in the main panel. Too easy to make it a better, safer installation by running a EG conductor back to the main panel's grounding bus. Plus, not a good idea to use conduit as an EG when there are concentric/ecentric K.O.s. Believe it violates NEC; 90% sure. You can't rely on the knockout for grounding for circuits that are over 250v or for the bonding of the service. As far as I know, the knockouts aren't a problem on branch circuit equipment grounds. You make a good point about the paint. If you're using the EMT as the equipment ground, and if the box is painted, then you're supposed to remove the paint at the locknut to ensure a good connection. - Jim Katen, Oregon Link to comment Share on other sites More sharing options...
Tom Raymond Posted December 11, 2009 Report Share Posted December 11, 2009 "You make a good point about the paint. If you're using the EMT as the equipment ground, and if the box is painted, then you're supposed to remove the paint at the locknut to ensure a good connection." So how common is it to see the paint removed? And shouldn't the same prep be at the accessory ground bus in the disconnect (or any accessory bus for that matter)? Tom Link to comment Share on other sites More sharing options...
randynavarro Posted December 11, 2009 Author Report Share Posted December 11, 2009 And shouldn't the same prep be at the accessory ground bus in the disconnect (or any accessory bus for that matter)?Tom I would think because the equipment is assembled at the factory, that those bond and connection points are ok. It's when field modifications are made that the paint may become a problem. I could be wrong though. Link to comment Share on other sites More sharing options...
Jim Katen Posted December 11, 2009 Report Share Posted December 11, 2009 . . . So how common is it to see the paint removed? And shouldn't the same prep be at the accessory ground bus in the disconnect (or any accessory bus for that matter)? Uncommon. At the accessory grounding terminal, I believe that the electrica connection is made via the mounting screws. - Jim Katen, Oregon Link to comment Share on other sites More sharing options...
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