More likely IMHO to be rats chewing on cables and damaging the insulation.

Rat urine, like any other urine, is however slightly conductive, so rat urine over live parts such as terminals in junction boxes COULD start a fire.

Salts contained in urine attract moisture, which never completely dries and remains conductive forever.

Current passing through the remains of a dead rat could also start a fire.

rat urine conductivity depends on what the rat has been eating -actually you can use this experimentally, to measure how diuretic certain plants or medicines are.  However, like any salt water spill on its own it is not very likely to start a fire, but it may cause a lot of hissing and spitting.

I'm with broadgage  on this - rats are likely to have done other damage in addition to just peeing, that contributes to the fire risk - they chew insulation from cables, make nests that block ventilation ducts and may even die straddling live terminals.

Mike

Aren't the Belgians grateful for a small boy's pissing on a fire? ?

Being very experienced I would agree that it’s going to be chewed cables rather than because they are wet.

Removing salt from water the natural way………..

Rats.

I have seen scorched mice on consumer unit terminals