Section 278(3) in The West Bengal Motor Vehicles Rules, 1989
(3)The joints in any insulating materials as aforesaid shall be either-(a)overlapped by not less than 8 centimetres; or(b)butted with a covering butt-strap of the same material and thickness not less than 13 centimeters wide, and overlapping the butt-joint equally by not less than 6 centimetres.
