Cable identification question

[ColJack]

If the units are 3 phase & it is possible to simultaneously access 2 different phases, then the unit should be labelled with "WARNING 400V" at least.

that's what we do.. if it's a 3 phase terminal box ( such as the connections on the compressors ) then any single phase connections in there ( such as the protection modules or crank case heaters to stop the oil from solidifying ) then it's wired in the relevant colour for whatever phase it's on..

Can I ask a silly question? Why aren't all units wired to the same spec??

about 85% of the units we make are bespoke.. we make standard units for BT, but everything else is designed and built to suit the clients spec..

this involves the use of at least 4 different panel makers..

only very occasionally does this crop up as most of the time the sockets and lights are on the brown phase.

 

[TicklyT]

........ The output of the MCB was chained to the input of the fusefolders using blue wire. .....

That sounds like the colours usually used by BT... Blue is -50V or -24V DC, and black is the ground (+ve earth)

Strowger 'clockwork' exhanges used to use red and black... Black was -ve so 'live' and red was +ve and usually grounded