What Type of Bolt Used in HT End Termination......????

How about a telephone call to the HT End termination's manufacturer if, indeed, it doesn't already say in the sales literature or instruction sheet supplied with it?

Stainless steel bolts can be used in pretty much any electrical connection no matter what the material of the terminal and what it's being bolted to.

If any of the components are aluminum, SS is preferable to prevent galvanic corrosion.

Brass (do you mean silicon bronze?) bolts might be used if the materials being bolted are copper or bronze, but SS will work fine for these also.

Cadmium plated should not be used for outdoor electrical connections, since you will not get the corrosion resistance needed. In a clean, dry, indoor environment they might be used, but are not preferred.

I was always taught to never use SS hardware with Al.

Has that changed?

As long as I've been in the electric contracting & utility business (20+ yrs now), we've been using SS hardware for electrical connections. I'm sure it depends on the grade & alloy of hardware - I think what we use is 316SS. I've not seen any sort of corrosive or galvanic reaction of SS with aluminum, but have seen other types of hardware corrode and deteriorate.

Thnks sir for ur valuable reply...... we are recomemded to use SS or cadmium bolts... i heared we cant get pure SS bolt it is only SS plated bolt... it tat true....

It is not possible to plate an alloy on top of a base metal. Electroplating doesn't work like that.

With the recommendation already to hand, why ask the originally-posted question?

i heared we cant get pure SS bolt

In the industry these are as common as dirt, just more expensive.

only SS plated bolt

This is completely untrue, perhaps you misheard.

SS hardware is very common in aluminium to aluminium HT connections, the trick is to ensure the use of large surface area load spreading washers and an anti loosening device that can maintain constant pressure (such as a spring washer, not a locking compound) to ensure that the two aluminium surfaces remain under tension throughout the life of the joint.

After all, the stainless steel fittings are not there to pass the current they are there to keep the joint together.

The termination it is not provided with any bolt. At the end of the cable termination it is a lug.

Copper, aluminum and bimetallic cable lugs and splices are designed for medium voltage cable crimping applications. HV cable lugs and splices are made from high purity copper, annealed and tin plated with extended barrels for reliable high voltage electrical connections.

The lug is connected with the bolt of a high-voltage apparatus as breaker or disconnector or direct to busbar, transformer or motor.

The bolt is designed to withstand high compression force required in order to decrease the contact resistance [mainly in a short-circuit case].

Cadmium covered carbon steel could be a solution. High carbon stainless steel could be better.

The best bolting material for an electrical connection is the same as the material being joined and that is particularly true if the connection will be subject to thermal cycling. On aluminum deadend jumper pads, for example, the optimal bolts are 2024 AL. Many mistakenly believe that SST bolts are superior. They are not but if SST bolts, nuts, washers are used, they should include a Belleville spring washer with appropriate spring characteristics to ensure they do not flatten and will maintain spring loading of the bolted assembly. It is equally important to use a contact aid/sealant of the appropriate thermal rating on the properly cleaned and prepared joint prior to bolting to ensure a sealed low resistance connection.