GEC bond

[76nemo]

Had to put in an outdoor SquareD service panel today for an empty lot, (pole mounted). The grounding bar is isolated from the box itself. It was freezing cold and the bonding screw had ******* threads. At 10 degrees on the river bank, I wasn't cranking anything to try to make the threading. I am curious. Does it say anywhere I can't bond the box to the GEC, and NOT use the bonding screw on the neutral bar???? That's where I was going, but I didn't know if it was allowed. I was frickin' freezing, so I just went on and will return over the weekend, not a rush job.

So,..... question stands. Does it state anywhere in code I MUST use the bonding screw if the box is bonded otherwise?????

 

[LarryFine]

So,..... question stands. Does it state anywhere in code I MUST use the bonding screw if the box is bonded otherwise?????

Yes, the neutral bus and the enclosure and GEC must all be bonded together.

You should still land everything on the neutral bus, and connect a conductor from the neutral bus to the enclosure.

 

[76nemo]

I lost you there Larry. This panel supplied by the GC only has one grounding bar. The bar is isolated from the box. The GEC and neutral are tied together in the wiring, but the box would remain isolated if the bar is not bonded. I thought of bonding the GEC at it's entrance. I wasn't about to cut corners, but it crossed my mind. The threads on the bonding screw were messed up from the package, and I wasn't about to force it. It was 10 degrees and -6 with the wind chill. My boots and denim somewhat told me the wind chill degree wasn't factored on a river bank with 10 mph wind. I wasn't there long, but brother, I got cold quick!!!!

 

[e57]

Drill a hole - install a lug, and a proper sized jumper. Or re-tap the hole. Are you sure the threads were messed up. Not many of the panel backs are tapped - the screw should have a set of notches cut in it for "self-threading"...

Anyway. Back in the day - which was not long ago - you would need to do your own bonding work before thay came up with the silly screw - and they have not outlawed it....

 

[76nemo]

Drill a hole - install a lug, and a proper sized jumper. Or re-tap the hole. Are you sure the threads were messed up. Not many of the panel backs are tapped - the screw should have a set of notches cut in it for "self-threading"...

Anyway. Back in the day - which was not long ago - you would need to do your own bonding work before thay came up with the silly screw - and they have not outlawed it....

Trust me e57, the threads were are a mess, looked like the last 5 threads were semi-punched on one side, and no, the bonding screw wasn't a self-tapping screw. I thought of using a lug, but the more I thought about it, removing the powder coat and using an NM connector with No-Alox to bond the stranded #4 to the panel sounded like a much more secure bond. I wasn't about to cheat, but that's what I was thinking.

 

[76nemo]

So my question still stands. By NEC, is the bonding screw from the isolated bar required, or are other means allowed????

 

[LarryFine]

Trust me e57, the threads were are a mess, looked like the last 5 threads were semi-punched on one side, and no, the bonding screw wasn't a self-tapping screw. I thought of using a lug, but the more I thought about it, removing the powder coat and using an NM connector with No-Alox to bond the stranded #4 to the panel sounded like a much more secure bond. I wasn't about to cheat, but that's what I was thinking.

Trust me, an NM connector is not a good terminal for bonding an enclosure. I would try another bolt first, and tap the hole to suit your bolt if it helps.

You could also steal one of those screw-and-bendable-tab bonding jumpers that some panels come with (CH?), and make a hole next to the bus for the screw.

 

[76nemo]

Trust me, an NM connector is not a good terminal for bonding an enclosure. I would try another bolt first, and tap the hole to suit your bolt if it helps.

You could also steal one of those screw-and-bendable-tab bonding jumpers that some panels come with (CH?), and make a hole next to the bus for the screw.

Larry, I am going back with another screw. I am not cutting corners. I was just wondering if it said anywhere in code I was obligated to use a bonding screw from the bar to box, and not allowed to use another method, that's all.

 

[LarryFine]

Read 250.24 and 250.28.

 

[TOOL_5150]

I came across a resi service that had a floating netural bus, the bonding screw was missing [never installed] so I installed a lug on the box and ran #6 from it to the bus, inspector passed it with no questions.

~Matt

 

[glene77is]

76,

"It was 10 degrees and -6 with the wind chill."
This might mean that your tap would snap, being hard steel and you are twisting it.

Drill a hole, bolt a ground lug.

...

 

[Pierre C Belarge]

As Larry pointed out, the location for terminating the GEC is found in 250.24(A)(1) & (A)(4). Referencing 250.8 for the MBJ.

 

[Pierre C Belarge]

Brad

I thought you "upstate NYers" were a tough breed, what are you going to do when it really gets cold???

 

[iaov]

Brad

I thought you "upstate NYers" were a tough breed, what are you going to do when it really gets cold???

Brad is probably like me. A delicate ,tropical animal who just happens to be stuck in a frozen, God forsaken winter wonderland. What realy sucks is that in another month we will look back on the days of 6 degrees and fondly remember them as the "balmy days of late autum."