disc. grounding

[gotmud]

Hey went to wire a roof top a/c...inside the disconnect there was no ground bar/lug there...It used to be grounded by the previous person running sealtight from inside the building to the a/c disc....NOW the inspector says NO WAY can I use sealtight to ground an a/c on a roof as long as the disconnect is mounted to the a/c unit...SOOOO i'm running a ground through the sealtight to the disc...What do I hook it to.....

 

[augie47]

Depending on the size of the ground, I normally see a lug or a sta-kon bolted to the swich. 90% of the folks located one of the unused tapped holes on the switch of backplate.

 

[qcroanoke]

Hey went to wire a roof top a/c...inside the disconnect there was no ground bar/lug there...It used to be grounded by the previous person running sealtight from inside the building to the a/c disc....NOW the inspector says NO WAY can I use sealtight to ground an a/c on a roof as long as the disconnect is mounted to the a/c unit...SOOOO i'm running a ground through the sealtight to the disc...What do I hook it to.....

The ground bar that is listed for use in that disconnect. If not available ask the inspector
what he will accept.
But I don't see what having the disconnect mounted on the unit has to do with it.......

 

[Dennis Alwon]

I have never seen a disconnect without provisions for a ground lug or bar, neutral bar -- no but ground bar -- yes, but I use mostly residential discos. You can bolt a lug as Gus suggested and go that route.

 

[gotmud]

it's just a #10 ground....BUT my inspector all of a sudden says I can not use an L-70 lug bolted to the side anymore...Is this true? He said it has to be an approved UL listed grounding bar for that disc....WHAT???? I thought you could always bolt a L-70 in there and roll with that....

 

[gotmud]

The ground bar that is listed for use in that disconnect. If not available ask the inspector
what he will accept.
But I don't see what having the disconnect mounted on the unit has to do with it.......

Oh the inspectors here came up wih that a while back that if the disc. is mounted on the unit then a ground wire will be pulled because the unit vibrates and using the race way as a ground will eventually come lose due to the vibration.....:roll:

 

[qcroanoke]

it's just a #10 ground....BUT my inspector all of a sudden says I can not use an L-70 lug bolted to the side anymore...Is this true? He said it has to be an approved UL listed grounding bar for that disc....WHAT???? I thought you could always bolt a L-70 in there and roll with that....

Sounds like the inspector has been to a class or read the riot act about using only accesories that are listed for the disconnects not just any lugs that happen to be on the truck.......

 

[Dennis Alwon]

You should be able to use a green ground screw. Just drill and tape a 10/32 or 10/24 thread and use the screw. How could that not be legal. Or tape a ground bar in the disco.

Here is what the NEC states.

250.8 Connection of Grounding and Bonding Equipment.
(A) Permitted Methods. Grounding conductors and bonding jumpers shall be connected by one of the following means:
(1) Listed pressure connectors
(2) Terminal bars
(3) Pressure connectors listed as grounding and bonding equipment
(4) Exothermic welding process
(5) Machine screw-type fasteners that engage not less than two threads or are secured with a nut
(6) Thread-forming machine screws that engage not less than two threads in the enclosure
(7) Connections that are part of a listed assembly
(8) Other listed means

 

[cowboyjwc]

Remember to scratch the paint off if you use a lug.