I
Inteificio
Hi,
Just came across something earlier that made the have a think.
Distribution panel fed by 25mm cable.
This goes directly in to a D50 breaker.
The D50 feeds 4 6mm cables squeezed in top of the MCB that feeds small 3 phase bus bars, these in turn feed 1.5mm circuits.
I have fitted MCBs to cover the 1.5 cables, and was about to exchange the D50 for an RCD.
This made me think.
If I remove that D50 nothing is protecting the 6mm cables or the bus bar (10 mm) from overload.
If all of the circuits are in use then those 6mm wires will cook.
However no distribution board I have worked on has provision for this.
Discrimination lets us build the board, but what protects the board if it is overloaded?
It seems such a basic thing, but I asked all the sparkies on site. The response from all was similar, "good point, no idea what the regs for it are"
So do any of you guys know what the requirements are to protect bus bars/internal cables from overload?
Just came across something earlier that made the have a think.
Distribution panel fed by 25mm cable.
This goes directly in to a D50 breaker.
The D50 feeds 4 6mm cables squeezed in top of the MCB that feeds small 3 phase bus bars, these in turn feed 1.5mm circuits.
I have fitted MCBs to cover the 1.5 cables, and was about to exchange the D50 for an RCD.
This made me think.
If I remove that D50 nothing is protecting the 6mm cables or the bus bar (10 mm) from overload.
If all of the circuits are in use then those 6mm wires will cook.
However no distribution board I have worked on has provision for this.
Discrimination lets us build the board, but what protects the board if it is overloaded?
It seems such a basic thing, but I asked all the sparkies on site. The response from all was similar, "good point, no idea what the regs for it are"
So do any of you guys know what the requirements are to protect bus bars/internal cables from overload?