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Supply to A/C disconnect


randynavarro
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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. . .

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Does anyone check wiring connections inside the A/C housing?

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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.

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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

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"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

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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.

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. . . 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

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