To answer rad74ss’s question – I’m not sure. The cable appeared to be held down with aluminium strap-like clamps every metre or so – you can see these also in the photos. To be honest, I only noticed the strip when processing the pictures for posting here. Without the flash, it was somewhat gloomy and I was not aware of it. It looks like it could be double-side tape (?) but then I’d expect flies to be stuck to it! Could it be marking tape – i.e. the layout guy was not the installer or something to stop the varnish rotting the cheap plastic insulation?
