Northcliff, and places like Wilropark, are notorious lightning rods.
There is a Vodacom mast in Wilropark, that is frequently hit, hard!
When hit, it sends huge ground currents in approx 450m radius, and this induces around 2000V in any cable lying on the floor.
I live 200m away from that mast, so unfortunately now I have to have wireless, and every single wire sitting with a massive arrester behind it.
Due to the ground currents, the rule is that nobody is allowed outdoors when there's bad weather, not even the pets.
With the last strike, I found that the induced voltage in the phone line was a fraction of that induced in all my ethernet cables lying on the ground. Phone line runs on overhead. The three Ethernet cables that were on the ground, caused terminal damage to the equipment they were attached to, we're talking vaporised components, holes burnt into PC boards. If the ADSL had been plugged in, I reckon it would have survived because devices that had cables running through the roof, they didn't even reboot, nor were they disrupted. The blown HDMI port, its cable was on the floor.