UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - A question about overhead phone-lines.

G6Tanuki · 3rd Jul 2019, 10:54 am

All the photos of pre-WWII street-scenes have the 'classic' telegraph-poles with multiple cross-bars and a separate insulator for each wire.

Same goes for railway-lines of a similar age - poles, cross-bars, and multiple separate wires.

When exactly did the change to insulated-pairs take place? My parents' house was built in 1958 and that had a single insulated-pair incomer but this was still attached to one of the old black tar-and-asbestos type insulators. The incoming cable - after being looped round the insulator - disappeared up inside the base of the insulator and a thinner cable then came out the same way - from memory the top of the insulator unscrewed and there was a junction-box inside to transition from the overhead-wire to the wire which led to the phones in the house.

When did this change from paired bare-wires to insulated-pair take place?

Also, in the 1970s I remember seeing multi-pair cable strung between telegraph-poles and every 7 or 8 poles there was a thin yellow-greyish wire/tube running down the pole to some sort of fitting - to me it looked more like a tube-connector than a socket. What was this for? Did they pressurise the multi-pair cables somehow to keep moisture out?

3rd Jul 2019, 10:54 am	#1
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 14,007	A question about overhead phone-lines. All the photos of pre-WWII street-scenes have the 'classic' telegraph-poles with multiple cross-bars and a separate insulator for each wire. Same goes for railway-lines of a similar age - poles, cross-bars, and multiple separate wires. When exactly did the change to insulated-pairs take place? My parents' house was built in 1958 and that had a single insulated-pair incomer but this was still attached to one of the old black tar-and-asbestos type insulators. The incoming cable - after being looped round the insulator - disappeared up inside the base of the insulator and a thinner cable then came out the same way - from memory the top of the insulator unscrewed and there was a junction-box inside to transition from the overhead-wire to the wire which led to the phones in the house. When did this change from paired bare-wires to insulated-pair take place? Also, in the 1970s I remember seeing multi-pair cable strung between telegraph-poles and every 7 or 8 poles there was a thin yellow-greyish wire/tube running down the pole to some sort of fitting - to me it looked more like a tube-connector than a socket. What was this for? Did they pressurise the multi-pair cables somehow to keep moisture out?