Overlapping Length for the Busbar Joint

May i know whether there are any reference guidelines for the overlapping length requirement for the respective current carrying copper busbar?

Noted the importance of following are directly affecting the effectivelness of its performance.

a. Type of joint

b. Joint Resistance

c. COndition of contacts (burr, TInned Plated Surface)

d. BOlting arrangement

e. Ambient Temperature

f. Clearance between Bars and Phases.

We are are very much interested to know whether there are any reference guidelines to determine the length of the overlapping joint for the main and distribution, incomer to vertical/main horizontal busbar to advoid any possible overheating at the joints.

Thank you in advance