Why would my lights be effected in my garage when my neighbour turns his power saw on in his garage?, Garages are Joined.
The power to my garage comes from my bungalow consumer unit [15amp fuse] to an MCB consumer unit in my garage feeding lights and sockets.[sockets ringed]

bob, March 2009

Alternatively it could be because your power supplies are connected at the transformer.
It could be that the startup power drawn from your neighbour's saw is reducing the voltage in your garage just enough to make your lights (I'm assuming they're flourescent) to flicker.

What size cable feeds your garage lights?

Adam, March 2009

It is possible that your neighbour's garage is powered by you. Try knocking out your power (completely) and then see if he can use his garage power.

T, March 2009