I was looking through some old factory wiring schematics, where I have started a new job, and don't quite understand them (still an apprentice), and the guys here don't have an answer, so I'm hoping someone here might be able to?
There is an old ring main ran around most of the building in 50mm SWA with a 200A MCCB, which go to various tap off boxes. So SWA in, SWA out of the box, through 4 boxes, then back to the MCCB.
There is no fuse, or switch etc, just bus bar inside the tap off boxes.
From these boxes the cable changes to 25mm or 16mm SWA which then feeds distribution boards with various size switches/isolators on (125A, 100A and 160A etc).
My main query is, what is protecting the cable leaving the tap off boxes? As I know the 200A MCCB isn't?
From my limited knowledge, this surely isn't correct, although I am told they have been inspected and tested?
Thanks for any advice, as I don't really understand.
There is an old ring main ran around most of the building in 50mm SWA with a 200A MCCB, which go to various tap off boxes. So SWA in, SWA out of the box, through 4 boxes, then back to the MCCB.
There is no fuse, or switch etc, just bus bar inside the tap off boxes.
From these boxes the cable changes to 25mm or 16mm SWA which then feeds distribution boards with various size switches/isolators on (125A, 100A and 160A etc).
My main query is, what is protecting the cable leaving the tap off boxes? As I know the 200A MCCB isn't?
From my limited knowledge, this surely isn't correct, although I am told they have been inspected and tested?
Thanks for any advice, as I don't really understand.