S
sparks1653
I got an emergency callout today from a theatre i do a lot of work for. they had lost power to their stage lighting systems. after a visual inspection the neutral bar of the isolator has melted a lot and the cable discolored and brittle. obviously there is the fault!
i was thinking about just installing another 125a isolator, however there is no reason this fault wouldnt happen again, as nothing will be different. The cable supplying the isolator is bolted straight to an incoming bus bar setup. then through the isolator to a 125a 3p-n-e socket. it is then broken down into 3 x 63a single phase sockets each one supplying a dimmer rack for their lighting systems. each one on a separate phase.
the reason this is unpredictable is for every show the load balancing on each phase is different, so i need the most versatile safest way of resolving this.
i came up with a few different ideas and wanted advice on which sounded the best. or if anyone has a better idea.
1) come off the bus bar supply into a 3-p-n-e distribution board then have 3 x 63a single phase breakers suppling SWA supplies to each 63a socket
if i do this would it still be a good idea to have an isolator near each socket even though they are close to the distribution board, or would that suffice?
2) same as existing, come off the bus bar supply into a 3p-n-e 125a isolator, then to a 125a 3p-n-e socket and then split down to 63a single phase sockets (doesnt seem logical to me)
3) come off the bus bars with 3 separate cables - 1 off each phase, into 3 separate 63a single phase fused rotary isolators each one supplying a 63a socket
4) some combination of all of the above!
i was thinking about just installing another 125a isolator, however there is no reason this fault wouldnt happen again, as nothing will be different. The cable supplying the isolator is bolted straight to an incoming bus bar setup. then through the isolator to a 125a 3p-n-e socket. it is then broken down into 3 x 63a single phase sockets each one supplying a dimmer rack for their lighting systems. each one on a separate phase.
the reason this is unpredictable is for every show the load balancing on each phase is different, so i need the most versatile safest way of resolving this.
i came up with a few different ideas and wanted advice on which sounded the best. or if anyone has a better idea.
1) come off the bus bar supply into a 3-p-n-e distribution board then have 3 x 63a single phase breakers suppling SWA supplies to each 63a socket
if i do this would it still be a good idea to have an isolator near each socket even though they are close to the distribution board, or would that suffice?
2) same as existing, come off the bus bar supply into a 3p-n-e 125a isolator, then to a 125a 3p-n-e socket and then split down to 63a single phase sockets (doesnt seem logical to me)
3) come off the bus bars with 3 separate cables - 1 off each phase, into 3 separate 63a single phase fused rotary isolators each one supplying a 63a socket
4) some combination of all of the above!
