Replacement set screws for main breaker

[jjpp]

I need to find replacement set screws for my main breaker and no one seems to have them and was wondering if anyone knew of an online source.

I have looked at the big box stores and tried a couple of electrical supply houses with no luck. Tried several lugs and the set screws are either the wrong size or too short. The screws are 3/8" x 24pitch thread.
I have a Siemens 100amp panel and it requires 110 in lbs on the aluminum flat head screws and even with a new bit they spread. Not sure why they would use flat head screws on the main and allen heads on the neutral and ground lugs????

Can stainless ones be used in place of the aluminum ones? That is all that I can seem to find.

 

[ForceFed70]

Find a 3/8x24 bolt, cut off the head at the length you need and use a dremel to cut a slot in one end? Kinda ghetto but should work.

 

[rlitman]

You're SOL. Aluminum set screws in breakers and electrical lugs are a special alloy. I've never seen them sold separately, and it would be a violation of code to replace them, as the breaker itself was UL rated only when used with the supplied set screws.

Don't worry about using a new screwdriver bit. Get one that actually fits. And is parallel ground.

 

[rlitman]

Find a 3/8x24 bolt, cut off the head at the length you need and use a dremel to cut a slot in one end? Kinda ghetto but should work.

NO NO NO NO NO! You cannot use a steel screw in a circuit breaker. The thermal expansion and contraction will cause it to eventually back out, and it will start a fire.

 

[ForceFed70]

Aren't they normally steel or stainless steel? They certainly aren't copper and seem too hard to be aluminum.

Edit: Saw above - special aluminum alloy apparently. Had always thought they were steel.

 

[ishiboo]

Time to replace the main breaker.

 

[jjpp]

I used a bit that fit properly, it's just that 110 in lbs is quite a bit of torque for a flat blade. And I have already considered the thermal expansion that is why I am asking for a source for the proper aluminum replacement.

 

[ishiboo]

I used a bit that fit properly, it's just that 110 in lbs is quite a bit of torque for a flat blade. And I have already considered the thermal expansion that is why I am asking for a source for the proper aluminum replacement.

As mentioned, they won't be sold separately... to save some time you can pull them from a new identical main breaker, but I'd install the whole thing.

 

[DenisG]

I need to find replacement set screws for my main breaker and no one seems to have them and was wondering if anyone knew of an online source.

I have looked at the big box stores and tried a couple of electrical supply houses with no luck. Tried several lugs and the set screws are either the wrong size or too short. The screws are 3/8" x 24pitch thread.
I have a Siemens 100amp panel and it requires 110 in lbs on the aluminum flat head screws and even with a new bit they spread. Not sure why they would use flat head screws on the main and allen heads on the neutral and ground lugs????

Can stainless ones be used in place of the aluminum ones? That is all that I can seem to find.

My panel is a Square-D brand with QO style breakers. They use 5/16 -24 set screws and you can pick them up with a magnet (most likely plain steel ones).

 

[rburke65]

Have you stopped at a local electrical supply store or contractor and asked if they have an extra or an orphaned screw? All they can say is "no".

 

[jjpp]

Yes and they couldn't help much. One place had a lug with the proper screw but it wasn't long enough.

 

[G_P]

BEst bet is to ask some electricians if they have replaced a similar panel and have the old one still in the junk pile. But I doubt they would want to assume the liability and would just offer to come and change the whole breaker.

 

[MrMark]

Are you using a torque limiting screwdriver or some flat head bit socket in a regular torque wrench? As you figured out, the hardware in most residential electrical equipment is not very robust to say the least. I would replace the breaker as suggested but realize that as tight as you can get it in its current deformed state will be tighter than 90 percent of the ones out there in the field. Every one of this type I have ever seen is deformed to some extent. They are just junk screws and they obviously shouldn't be flat head but for some reason some manf do it this way..

 

[jjpp]

I used a flat head bit in my torque wrench but made sure that it fit well before even attempting to torque it because I was fearful of exactly what happened. I use a torque wrench everyday and am confident in my abilities but feared the worst.
I am just concerned with the torque because of the aluminum wire other wise I would feel confident with how tight they are.

 

[jjpp]

It is upsetting that they used allen head screws on the neutral and ground lugs but flat head screws for the most important ones on the breaker???

 

[MrMark]

I will say that torquing the lugs on a service entrance or panel with a torque wrench is a scary proposition. The torque spec is way tighter than you would ever go by hand. When I did mine on a Siemens I was very apprehensive that they would shear off. The guys at Edison just rattle them on with an impact and they are no where near torque spec as I put about another turn on mine with the wrench with the linesman after they used their impact. They quote from the linesman was the impact was "Edison spec" and they wouldn't go any tighter because all these panels are "$hit." They didn't want to break it, and I don't blame them, but I was willing to give it the proper torque.

My attitude is always that if something is going to get broken then I am the one that is going to break it.

FWIW, I've never seen an electrician with a torque wrench. I'm sure some have them but they are very rare in residential. My Edison guys didn't even know that a torque wrench existed.

 

[MrMark]

Put a little no-lox in the lug before tightening with the AL wire.

 

[jayrush13]

http://www.oregonbreakers.com/

Try these guys they recycle breakers and refurbish them they would probably have the screws

 

[jjpp]

I did, and will still check a couple more places to see if I can get replacements but thanks for setting my mind at ease MrMark.
I will still recheck them a couple of times after some use.
I think next time I will buy some stainless screws and use them to set the wire and then reinstall the aluminum ones and torque them properly when done.

 

[jjpp]

http://www.oregonbreakers.com/

Try these guys they recycle breakers and refurbish them they would probably have the screws

Thanks will check them out.

 

[MrMark]

I did, and will still check a couple more places to see if I can get replacements but thanks for setting my mind at ease MrMark.
I will still recheck them a couple of times after some use.
I think next time I will buy some stainless screws and use them to set the wire and then reinstall the aluminum ones and torque them properly when done.

You want to just torque these and leave them alone. If you read the info on the panel usually if you retorque you have to go higher spec. The wire crushes as it is torqued and you want that crush to just the right amount. When you retighten you risk crushing the wire too far and it could be weakened or even break.

 

[jjpp]

Understand, thank you.

 

[Ross/Kzoo]

http://www.aflglobal.com/Products/C...-Purpose/Alnox-Electrical-Joint-Compound.aspx

This is what our linemen use on the electrical connections at the house. I occasionally use it when I want good electrical contact such as battery connections.

 

[Norcal]

If you replace the factory set screw, you just voided the UL listing. Replace the breaker.

 

[jjpp]

Thanks for the replies.
This just ***** because the panel is new as in never seen electricity and a new main is as much as the panel cost. Stupid 12 cent screw is going cost me at least $50 and unless I buy a different panel I fear the same thing will happen again if the proper torque is applied to the stupid flat head screws.

 

[Dustball]

Thanks for the replies.
This just ***** because the panel is new as in never seen electricity and a new main is as much as the panel cost. Stupid 12 cent screw is going cost me at least $50 and unless I buy a different panel I fear the same thing will happen again if the proper torque is applied to the stupid flat head screws.

Since it's new, can you warranty it?

 

[wyliesdiesels]

If you replace the factory set screw, you just voided the UL listing. Replace the breaker.

^^+1

Amazing how people dont realize that they can violate a U/L listing until an insurance policy wont pay out on a fire damage claim!

 

[KANSASBOY]

Try looking under lug not set screw also look at something like this you can take the lug out ofhttp://www.lowes.com/Electrical/_/N-1z0yt4x/pl?Ntt=lug#!

 

[sweetcretin]

Have you contacted Siemens?

I had a bus bar that cracked in my Siemens panel. I called and complained; they replaced the whole thing at their cost. The only catch was I had to wait for their electrician from out-of-state (They also brought in a local guy.). Their electrician did a teardown similar to what we do at work. He recorded the entire thing, measured torque on every fastener, and had me fill out pages of documentation. In the end, their electrician took the broken panel with him.

Just saying it can't hurt. I've been surprised by numerous companies lately.

 

[Mr_fixit]

YOU sure you used an INCH pound wrench?

 

[ishiboo]

^^+1

Amazing how people dont realize that they can violate a U/L listing until an insurance policy wont pay out on a fire damage claim!

Find any example of an insurance policy denying a fire claim because a screw was replaced in a breaker/main breaker/etc. This is urban legend. The only way it MIGHT happen is if it was negligent (obviously wrong size, rigged in, etc.) AND the cause of the fire.

 

[jjpp]

NO, WOW I almost got to 110 FOOT lbs on a 3/8x24 aluminum flat head screw.


Yes with the INCH lb torque wrench that I use every day at work and has recently had the calibration verified.

 

[Mr_fixit]

Sarcasm. I get plenty of that at home! That's useful.

 

[jjpp]

I can see why.