OVERHEAD CONSTRUCTION
TERMINATION AT CUSTOMERS PREMISES

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Prior to the 1960's the telephone line always had a protector fitted as it entered the premises.  Originally this was a lightning protector which was just three serrated plates, one connected to earth and the other two connected to the line.  The plates were in close proximity to each other and in the event of a lighting being inducted into the external line, the lightning was to short across the gap to earth.

This setup was later enhanced with the protection consisting of protector electrodes for lightning, fuses for over current situations and heat coils for sustained currents that would not blow a fuse.  There was a similar setup on the exchange Main Distribution Frame (MDF).

In the 1960's no customer protection was provided unless there were more than four overhead spans and the protection was for lightning only.  At existing installations the protectors were removed and the fuses replaced with dummies during maintenance visits.

Many protector boxes were left in situ as removal would probably mean a re-paint or re-paper of the wall surface left exposed.  In some instances the wiring, both in and out, were just joined on two screws only.

Typical installation
The Protector is above the window, on the right

Last revised: April 15, 2023