Preferred Medium voltage bolt material

Is this in a saline environment?

Yes, it is a production facility and will be installed 130 miles off the coast of Louisiana.

SS bolt with a silicon bronze nut. Good belville washer(ss). Tightens well and resists galling.

Only use once. Trying to reuse, does increase the galling chances.

One also has to be cognizant of thermal expansion when selecting fastener materials for electrical connections. In almost all cases, the best and most reliable connection is achieved by using properly installed fasteners of the same material as the components being joined.

The composition of the bolts is a moot point. What you need to concentrate on is using electrical joint compound or anti-seize and torquing to spec.

I'm a licensed Journeyman electrician (3rd state to be licensed in) and have bee for 16 years

The composition of the bolts is definitely not a moot point when the bolted joint is thermally cycled. Differences in thermal expansion can ultimately result in loosening if the bolt expansion exceeds that of the contact material. Relaxation of the bolt tension decreases contact pressure and increases contact resistance.

Tightening to the specified torque is certainly important (and I'm sure you always use a torque wrench).

However, use of an electrical joint compound (EJC) is only one aspect of a properly made low resistance electrical connection. First, the proper EJC (gritted or non-gritted) must be used on freshly cleaned conductor and connector contact areas. This is particularly true for aluminum because aluminum oxidizes rapidly upon exposure to air and the resulting oxide is non-conductive. That oxide is typically removed and prevented by applying the correct EJC to the contact surfaces then wire brushing through the EJC with a SST wire brush.

Correct the bolt composition is key in this application as we are discussing large 5kv motors starting and stopping under varied load along with turbine generators. I just do not think 316 stainless in the best material and have had trouble finding the data to support, in these applications there are no aluminum components all of the bus connections are copper.

Since you are dealing with copper or copper alloy bus connectors, the best fastener material for your application is silicon bronze. SST would be the next best.

Anderson Electric publishes a very good Reference on proper connector installation, etc. which you can view and download at www.hubbellpowersystems.com.

From that home page, select Literature then Hubbell Power Systems Catalogs, Anderson/Fargo Connectors, Distribution, and finally Section DJ Reference Data.

That reference is also included in the printed catalog, which you can request.