Electrical Bus Bar Torque Specs

Typical hardware for bolting listed lugs to bus bars.

Electrical bus bar torque specs.

I am a firm believer in using manufacture torque requirements i have been in the mining industry as electrical troubleshooter for 30 years and over 90 of failures caused by tightening methods i also will move the wire around and torque again this has proven to help in maintaining torque specs when wires are moved into position to close cabinet. Reduce torque by 20 when cadmium plated bolts are used. Bus bar and terminal connections. Diameter of bolt used should be compatible with hole in tang.

Hexagonal bolt grade minimum sae grade 2 unc coarse thread. Zinc plated to retard corrosion and installed with the proper torque this hardware has a long history of satisfactory performance with both copper and aluminum bus bars. Use the torque specifications in. All of the major companies who manufacture electrical components have torque specifications for their equipment ask for it.

Ensure you know the torque specification. Importance of torque in bussing a critical concept in understanding bus lug torque specifications is the fact that the pressure of the lug connection has more to do with lowering the resistance of the electrical connection than the size of the lug itself. Have the bus bars cleaned annually with clean dry. For 60 hz current table gives bus bar cross sections which will probably be large enough for ampacities within each range.

Tm 5 683 nawac mo 116 afjman 32 1083. Ul test assembly procedures ul486a b. Then check table 1 to verify that size selected has the necessary ampacity. Typical busway installation.

Connections can create electrical noise power quality issues by vibrating and creating arc at the connection. Plated sae or stainless steel flat washers to be used on both sides. Knowing required ampacity determine possible bus bar dimensions from the table. Ensure your electricians own and know how to use a torque wrench.

Assume that required ampacity is 185 amp at 30 c rise. The most common size used is 1 2 13 but 5 8 11 hardware is used for some very large joints and sizes.