Loctite(R) in Electrical Connections

[mc5w]

Does anybody have any experience with using Loctite(R) or any other thread locking compound on the threads of box lug setscrews, split bolts, and so forth? The application would be a machine that has a lot of vibration such as a punch press or vibratory finisher.

I know that thread locking compoounds are not UL Listed but neither is Ilsco Deox which is an excellent oxide inhibitor. If you are following the recommendations of the Consumer Product Safety Commission and cleaning the strands of copper or aluminum wire with #220 or #240 silicon carbide abrasive paper and gooping them up with joint compound then there should not be a problem. The old Signal Corps method was that wire strands had to be cleaned using diagonal cutters or sandpaper so that all the wire strands will be conducting regardless of whether or not the connection is soldered. The reason for the continuation of the myth that solder is the best way to connect a wire is that you have to clean all the strands and there are fluxes that will do that for you.

If all of the wire strands are bridged by virtue of cleaning away all metal oxide I do not see where it is a problem that a setscrew or nut is insulated by applying a thread locking compound.

Oh, I have found that #220 or #240 garnet abrasive paper also works if semiconductive grit from silicon carbide paper would contaminate insulating surfaces. Garnet paper is not as efficient as silicon carbide which means that you would need to use more elbow grease.


Mike Cole, mc5w@earthlink.net

 

[TMD]

For what it's worth, we've used a Loctite 271 on terminal set screws. It's a good thread locker but also a good insulator. To much led to poor electrical contact. We still use it, but with due diligence.