First mention here of a Circuit Breaker was the old Voltage Controlled ELCB's, under the 1935 regulations.
And these were installed (as most thing's were back then) by your Friendly Power Supplier.
The 1955 EWR's were enough to make an Electrician cringe!.
They called for nasty things like seperate switches on motors and control circuits.
If the '55 Regs weren't enough the 69 Reg's really broke the donkies back,calling for silly things like D Curve breakers on Motor circuits and C curve breakers on everything else.
Some people that were working in the field,at the time are still seeing stars from this dramatic leap in thinking.
And then came the '76 Regs, this was a better way of thinking, we still had porcelain fuses but thier days were numbered, as far as Domestic switchboards were concerned.
But enter the NZI Flush-board, sure it had all the MCB's, but it would only take the NZI branded MCB's.
And the board had a live busbar that ran the whole length of the panel, no shrouding, many an Electrician here welded thier screwdriver to the back plate with that type board.
Meanwhile we still had the old Phenolic surface board, under the '76 Regs, Electricians could basically put what they liked on them, provided ther were no live parts.
The Overhaul of the Electricity Regulations stopped all of this in 1992, however and MCB's have been used ever since, for fear of retribution from the EWRB here (and others)
The regulations were changed to a Australian/New Zealand Standard in 2003, now we do the same job but it costs us so much more to be "safe".
