Thread: Screw through Main

Today I was looking at a Cutler Hammer panel and there was a screw through the main throw. What would be the reasoning??

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Because it's "back fed", most likely. The screw is to keep the main from being sproinged loose, to use a technical term, by the service conductors. Did you take off the front? The service conductors are probably connected directly to the main, instead of to panel lugs.

The "Danger" sign above the main should read:

"Take this screw out before removing the panel cover and you'll quickly find out why it was there."

Aaron

A back fed breaker is required to be secured in place so the breaker cannot be removed by just pulling it out. A back fed breaker will have its exposed parts "hot", thus, the meter should be pulled before removing a back fed breaker.

All of the back fed breakers I have seen have a means of securing them which is not accessible from in front of the dead front cover - you have to remove the dead front cover to access it.

I would not count that screw and washer as securing the main for because it was back fed. I doubt that is even supposed to be there. Looks like someone drilled a hole between the two breakers and ran the screw into the back of the enclosure ... probably for the reasons stated John, but that just is not right ... at least not like anything I've ever seen a manufacturer do, and Mr. Professional Electrician is not allow to do anything like that.

I've seen panels like that, factory issue. I doubt it is an add-on. Did you take the panel cover off and check inside?

I have also seen these on the rare occassion in the past.

I see 'em like that all the time. I just assumed (I know, I know) it was ok. Guess I better find out. Mainly I'm happy to see ANY kind of fastener on a back-fed main.

The hold down is an Eaton-Cutler-Hammer part: kit BRHDK125. This model of CH breakers have a hole molded into the case block to accept a #5–20 screw, the idea is that you can verify that the breaker is secure with the deadfront in place.

Thank you Michael.

The hold down is an Eaton-Cutler-Hammer part: kit BRHDK125.

ECJ:

Must be Photoshopped.

Aaron

From todays inspection. Challenger panel. I have also seen it in Cutler-Hammer (like Reis). I believe both are manufactured by Eaton.

I learned something again today (like every day) ... Cutler-Hammer puts screws for back fed breaker hold down where those screws can be removed from the front (outside the dead front cover), which will allow the back fed breaker to verify the use of the name "dead front" cover ... remove that screw, remove the dead front cover, you are dead.

Gosh, I shoulda thought that one out myself.

Thanks guys, I now know that Cutler-Hammer does indeed make that "from the factory".

That warning sticker should state "DO NOT REMOVE THAT SCREW WITH THE DEAD FRONT COVER IN PLACE - ONLY REMOVE THAT SCREW AFTER THE DEAD FRONT COVER HAS BEEN REMOVED AND THE POWER *TO THIS PANEL* HAS BEEN SHUT OFF", but they didn't.