So I install a 3 tier DB and attempt to install a fork busbar (much better because it frees up the terminals for additional wires) on the top of the circuit breaker ... which is standard practise (in the top (line) and out the bottom (load) ) in SA ...everywhere else in the world in the bottom out the top ... but it doesnt work because there is no facilty at the top to fit the fork busbar ... only at the bottom.

Check the diffrent manufacturers:

CBI has the facilty at the top and the bottom ... the question ... are CBI breakers bi-directional?

Onesto only has the busbar facilty at the bottom ... however they have a line (top) load (bottom) clearly labeled on the breaker ... it doesnt make sense.

Hager have the facilty at the bottom ... their circuit breakers are bi- directional.

ABB has the facilty at the top ... I know because it was the ABB breakers which got me started with the fork busbar.


I have decided to start a new trend in SA ... all my DB's from today will be wired line in the bottom and load out the top.

I am hop9ing that the main switch is also bidirectional and the earth leakage is in the top and out the bottom ... it will save the hassle of installing tails from the bottom of the main switch to the top of the earth lakage ... then from the bottom of the earth leakage to the top of the circuit breakers ( what a waste of time and wire)

Wiring the DB in this manner will eliminate another issue of thermal heat generated when you cable tiethe loom nice and neatly around the DB.

It just makes sense wiring the busbar at the bottom ... I think CBI are not bi directional and they dominated the market for too long ... it time to move forward and do it the right way ... in the bottom and out the top of the breakers.

Din rail breakers are forward and so should be the fork busbar ... people have moved on form CBI ... it time do it right.