What sixty years does to a west-end installation.
Hazlehead grew in layers, from the 1920s council-origin estate through the 1930s interwar granite villas along Queen's Road and King's Gate, to the 1950s and 1960s post-war bungalows and semis on the private streets, with later infill and Countesswells new-build to the west. The older the layer, the more the wiring has aged, and the first thing an inspector reads is the cable itself.
The colour is a clue to its age. Black rubber is the oldest, red and black is older PVC, and modern brown and blue is the newest. Rubber and lead-sheathed cable, common before about 1960, is the real concern: the rubber insulation perishes, cracks and crumbles with age and heat. Its presence is close to a rewire trigger on its own, and it will not survive a board swap, because the brittle cores fracture the moment they are disturbed. Even the earliest PVC from the fifties and sixties goes brittle at terminations where it has run warm for decades.


