One for the electric's crew;)..
We have a need to implement a contractor based mains generator
changeover system. Of course this will need to be mechanically and
electrically interlocked so as not to send gennie power back up the
line;!. The gennie of some 7 KVA output will be controlled by an
automatic starter system.
Its a very simple system fed off a long "ish" 230 volt overhead and the
system is a simple mains incomer, RCD, thence to a Four way dist board
lights, and a small ring main, all of three sockets, and Two spurs
terminating in 16 Amp commando sockets which in turn feed Two 19 inch
These are on MCB's at 5, 32, 16 and 16 amps respectively. All single
Question is if we decide to put the changeover contactor system say
after the mains incomer i.e. on the tails from the meter what would the
recommend contactor amperage rating?.
Or would it be better of if we say had a small sub main after the "dist"
board, the only thing thats essential to supply are the 19 inch racks
the lights and ring main aren't that essential would it perhaps be
better and maybe safer to put them on a MCB of say 32 amps rating off
the main dist board.
Then take that the to the contactor changeover system and then the
output of that thence to Two off, separate 16 amp MCB's.
This would give the system a degree of protection in that the whole has
apart from the suppliers fuse (100 amp), a 32 amp MCB in line preceding
it. If this is done this way I presume that a 32 amp rated contactor
would be in order?..
Anyone any opinions good or bad on these contactors certainly cheaper
than most others?.