106. Height of trolley-wire and length of span .-A trolley-wire or a traction-feeder on the same supports as a trolley-wire shall nowhere be at a height from the surface of the street of less than 5.2 metres except, where it passes under a bridge or other fixed structure, or through or along a tunnel or mine-shaft or the like in which case it shall be suspended to the satisfaction of an Inspector [* * *].
