Typical Hardware for Bolting Listed Lugs to Bus Bars

Recommended reading: UL test assembly procedures UL486A/B
Hexagonal Bolt Grade minimum SAE grade 2 UNC Coarse thread
Washers: Plated SAE or Stainless Steel Flat washers to be used on BOTH sides
Diameter of SAE Flat washers and Bellevilles to be compatible to size of bolt
Where Bellevilles washers are used, both of the flat washers must still be used to protect tin plated aluminun faces from indentation and loss of clamping force. Only one Belleville washer per bolt is used when needed.
Belleville specification for minimum flattening force is to meet above chart based on size of bolt.
Diameter of bolt used should be compatible with hole in tang.
Typically the tang bolt hole is about 3% to 10% larger than the bolt depending on manufacturer and process used.
No lubrication is used on screws or nuts to avoid distorting the lug tang or the bus from overclamping.
A minimum of two threads of the bolt thread should show through the nut when tightened.
Consider use of Bellevilles for applications where vibration or other factors that could reduce clamping force over time (like differential thermal expansion of dissimilar metals including ferrous fasteners and non-ferrous bus/tang bolting).
Consider use of commercial anti-oxident grease for joints with aluminum tangs, bus bars or wire, mixed metals, damp condtions or any other conditions leading to some loss of clamping pressure on the bus or connecting wire.
Fretting wear or other contact wear can remove tin coatings on aluminum lugs causing aluminum to oxidize which gives high contact resistance. This must be avoided by proper installation practices.
Bus bars made of copper should not exceed 1000 Amps per inch squared of cross section.
Aluminum bus bars should not exceed 800 Amps per inch. squared of cross section
Lug manufacturers do not control the end use conditions consequently users must evaluate properly all the applicable engineering criteria and standards involved for themselves.
The information above is suggested for favorable conditions only.
Favorable conditions are typically enclosed, static, and free of moisture , vibration and excessive heat and cold.