FCSP - Stripped Lug Set Screw

[MJDore]

Finally got around to re-installing my FCSP. We moved last year so this is the second time it’s been installed and the heads of the T25 set screws already weren’t great. I was hardwiring #6 and pretty easily stripped out the Siemens lugs on both the lines in. Ugh. They’re so damn brittle that it didn’t take much. I’ve been on the hunt to see if they can be replaced but I’m guessing “no.” The grooves are a unique shape to fit the Zettler relays.

Anyone been down this path or have any ideas or lifelines? Many thanks.

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[Scorpio3d]

I assume the box part is stripped not the screw part?

 

[MJDore]

The screw threads look awful. Almost like they melded together. If I can get them out I can try another one to test the lug. But I’m thinking I can’t just put any screw in there, correct? Would need to be aluminum?

 

[Scorpio3d]

I would try calling Ford or maybe Siemens I believe is who made the FCSP for Ford?

 

[tls]

It had never occurred to me to consider what electrical lug set screws might be made of.

After checking a lot of sources, I'm skeptical that they're aluminum. Nobody seems to sell aluminum set screws in sizes smaller than 1/2". Maybe they're plated steel?

 

[Grumpy2]

Time for magnet test

 

[Jaime]

What is written on the side of the terminal? That would help track down the part.

 

[MJDore]

Siemens R817325 - Part number search hasn’t returned anything useful.
8-2/0
CU9AL 110A
CU7AL 125A

 

[Maquis]

If all else fails, I would 100% MacGyver it. Find the next larger size set screw, drill and tap. Put it all back together without the cover, charge at full power and measure the lug temperature.
Since we’re not sure about the material, use of electrical antioxidant paste would be a good idea.

 

[TaxmanHog]

https://lugsdirect.com/BuyRecognizedCollarConnectors.htm

 

[tls]

Looks like you could buy a few different CU9AL or CU7AL rated lugs and steal a set screw from one of them, whichever one is the right size. I agree that if the threads don't clean up nicely with a tap (use a roll-forming tap, they are better for thread repair than cutting taps) retapping to the next size up makes sense.

Interesting that even though the lugs are rated for Al wire, the overall unit is not.

 

[Itaintfastenough]

The screw threads look awful. Almost like they melded together. If I can get them out I can try another one to test the lug. But I’m thinking I can’t just put any screw in there, correct? Would need to be aluminum?

 

[Itaintfastenough]

These lugs on this Murray 100 amp breaker look like the ones you have

 

[MJDore]

These lugs on this Murray 100 amp breaker look like the ones you have

Great find!!! Will take a look. Many thanks.

 

[EVpower]

I am also looking for a replacement for this lug. The internal hex socket on the set screw is stripped on my FCSP. Fortunately, the screw was at the correct torque at the point it failed during a follow-up check.

The marking at the bottom of the lug indicates it is a UL Recognized component. That means it can be used as part of another UL listed system like the FCSP. However, it may be difficult to source the part in small quantities.

In my case, the internal socket was a 4 mm hex. A ball head bit has not been used on the failed lug.

Steve

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