Electricity & Water Nice

cliffed · Feb 10, 2024

Lights still on … even though everything else is under water

[ElectriciansForums.net] Electricity & Water Nice

littlespark · Feb 10, 2024

I’m sure the bottom of the post where access is, is IP rated for rain, wind etc…. Not sure about submerged.

nicebutdim · Feb 10, 2024

I'm quite amazed by this. That pole has to be filled with water and there's no way the cut out isn't also filled.

Chances of someone having replaced the cutout with a waterproof junction is basically nil, so the only possible explanation is magic.

westward10 · Feb 10, 2024

Why wouldn't it work? If that is a column on the highway what is it's circuit protection?

nicebutdim · Feb 10, 2024

westward10 said:
Why wouldn't it work? If that is a column on the highway what is it's circuit protection?

Isn't there a fuse in the cut out?

Scratch that. I'm thinking a cut out filled with dirty water is going to create a dead short.

littlespark · Feb 11, 2024

I wonder if it’s solar…. No cutout. All the gear is in the head

nicebutdim · Feb 11, 2024

littlespark said:
I wonder if it’s solar…. No cutout. All the gear is in the head

Solar streetlights generally have their battery where cut out would otherwise be located.

They also tend to have an obvious panel mounted at high level to avoid contact with vehicles or the heads of pedestrians.

I'm curious about the comment from @westfield not expecting water to have any effect. Clearly I'm missing something obvious.

davesparks · Feb 11, 2024

nicebutdim said:
I'm curious about the comment from @westfield not expecting water to have any effect. Clearly I'm missing something obvious.

Yes, the resistivity of water is relatively high so unless the live, neutral, earth are very close together you won't get enough current flowing to cause the fuse in the cutout to operate.

Pure water has incredibly high resistivity which reduces with amount and type of impurities in it.

davesparks · Feb 11, 2024

nicebutdim said:
Scratch that. I'm thinking a cut out filled with dirty water is going to create a dead short.

I doubt it would be anywhere near a dead short, probably upwards of a hundred ohms considering the distances between terminals in most cutouts.

The fact the water looks dirty doesn't necessarily mean there are a lot of impurities in it, the dirtiness will be solids suspended in the water rather than impurities dissolved in it.

freddo · Feb 11, 2024

I took a load of 28W 2D bulkhead lights down recently that were full to the brim with water from a burst pipe. The fittings were running happily under water, though the water was very hot from being heated electrode boiler style.

R-fur · Feb 12, 2024

When I worked for a DNO I attended many jobs were houses, substations etc. were flooded and still live, As westward says it just keeps working. Loads of times I have meggered pilc cables that were hard down, stick the fuses in and they work fine.