buzz bar rating

[shay.sparky]

I have a old library to test and today I found an opening to look at the buzz bar it's solid copper 25mm what would the rating of this be as 250a bs88 fuses are the power source for these power to 5 3 phase distribution units

 

[i=p/u]

well i think in the big green book somewhere it says 1mm of copper can withstand 100A without insulation, so its insulation that restricts the current in most cases

 

[shay.sparky]

I'm happy enough with that mate I will have a search to prove to the lads

 

[i=p/u]

i know ive seen it somewhere only books ive read in last few years was regs, osg and other electrical material.. someone will come along and point you straight to it as they get their wives to read to them at night

 

[Darkwood]

well i think in the big green book somewhere it says 1mm of copper can withstand 100A without insulation, so its insulation that restricts the current in most cases

Think you maybe mistaken for fusewire ratings .... busbar systems have to be structurally sound to clamp to and carry fault currents way in excess of their rating ... i would be inclined to think the correct busbar has been fitted if the front end isolator is 200A rated, the rating can often be found on the rear side of the front panel but without that id be checking the feed tails show no heat damage as they would if the busbars were getting hot assuming current demand was their to do so..... its a pretty dumb mistake to fit an undersized busbar to the incoming fused isolator and ive yet to see an installation like this... the most common issue is busbar clamps been doubled up and because they come in different clamp ratings (100A, 200A as examples) its easy for a clamp to be overated by future installation works adding supplies on to existing clamps and if found should be rectified unless you can ensure the multiple loads attached cant overload the clamps.