So I have a dude who has bare 10mm copper conductors strung across various parts of his shop in pairs, no more than 5 meters long, with 12 volt halogens connected to them fed from a various size safety isolating transformers contained in metal ventilated enclosures in the roof. The transformers range from 200 VA to 350 VA, depending on the number of halogens he has on each pair of conductors. From the the transformer, which either are fused with fast blow glass type, or are "short circuit proof" a 2.5mm cable or a 10mm (depending on the size of the transformer) cable, insulated, is crimped onto the bare 10mm cables, the longest run of this cable is about 2 meters. If I read the bible correctly, does it require that every secondary circuit, the low voltage side, need to have an overcurrent protective device as it say in 188.8.131.52.2? I don't really see a problem with it, if the transformers become overloaded they are covered the fast blow fuse in the transformer on the primary or a thermal cut out or are "short circuit proof". The transformers are designed for this kind of thing so why do i need to fuse every secondary circuit. I could understand if it was just a standard transformer but these are designed specifically for lighting and if the regs required you to have extra over current protection on the secondary side the surely they woudl be sold with that built in.
The circuits feeding the primary have been wired in 1.5 single and the max load on any circuit is 6 amps, cable protected by 10 amp breaker. The bible says about (184.108.40.206.2) that 200VA shall not be exceeded if a converter is used when supplying bare conductors, I presume is ok to exceed 200 if using safety isloating transformers.
I can't find any info on sans 60590-2-23 or 60998-2-1 or any of the other sans numbers mentioned in this section of the bible(7.9)
Originally before i got there there was 65 x 50 watt halogens on one circuit and its been sitting like that for the last 8 years with no problems, apart from and insane volt drop (170 Volts at the furthest point) and the fact it was covered by a 20 amp fuse.
Thoughts? Does it comply? I don't see a problem as the transformers are safety isolating, designed for low voltage lighting and have built in protection and the circuit are no where near overloaded now(volt drop is a consideration of course on the secondary but changing the 2.5 to a larger cable will solve that).
There are a lot of transformers(about 35 ish i think) and installing a circuit breaker in everyone will be a pain.