Originally posted by: alancapon
Originally posted by: ArthurHall
. . . Radials are safer as the interlocks tend to work with you, where on rings it is possable to close an earth switch onto a live cable. . .
I would suggest that the the earth switch should have a fault-making rating to allow you to do so. Closing an earth onto a live cable is one of those things that can happen.
...and possibly get the earth switch interlocked with a capacitative voltage presence indicator like on the Siemens units i've seen. No substitute for proper procedures and training though.
I assume the RMUs will be ring-main switches and a SF6 or vacuum CB for the tee-off, and the ring will be operated in open mode? The main disadvantage of the RMU is that maintenance is more difficult; you must isolate the whole unit.
Everyone loves a fireman - but hates the fire inspector.