Don't forget that this is a view only a 'qualified electrician'
should have access to. Once the cover (with CB blanking plate) has
been refitted, it's all perfectly fine.
The 'qualified electrician' will know to use the 40A 2 pole isolator
switch to disconnect that three pronged busbar before attempting to
install a third CB (I'd expect the cover is designed to require the
isolator switch to be in the off position before it can be removed
anyway -BICBW in _this_ case).
The experienced 'qualified electrician' will also know to verify that
the isolator switch _has_ actually disconnected the live by using his
trusted meter or neon screwdriver (after verifying that his chosen
instrument of test is still capable of indicating the presence of
mains voltage before switching off).
It should really come as no surprise that removing the safety cover
off any consumer unit _will_ reveal exposed and accessable live
metalwork. Admittedly, in this case, that clipped on bit of plastic
seems a little pointless considering the approved handling practice by
the 'qualified electrician' when working on such kit is supposed to
prevent such 'accidental contact' as seems to be its purpose.
You can get the front cover off most CUs without turning off the main
switch. The real work of art is removing or adding MCBs without turning the
power off. Removing MCBs is usually harder than fitting them when the power
You've drawn two phase (live) conductors leaving the CU but
only one neutral conductor returning to the CU.
Your qualified electrician can't join the neutrals somewhere
in the garage and run one neutral back to the CU. The two
circuits leaving the CU have to be kept separate from each
other and must return to the CU on their own neutrals.
(Wiring reg 314-01-04.)
*If* there was another MCB then I guess the shroud would do a moderately
good job of shielding the live terminals but given that with just a smidgen
of determination you could electrocute yourself from multiple points within
that unit, I'm not sure why you're worried by that unshielded terminal
(that will be out of harm's way once you've closed the box up).
The shroud is a nicety - to reduce the contact area should you need to
work while some other circuits are powered.
However, for this example of 2 breakers, and I woudl say, for any
domestic case, there is not reason at all you should be working in a CU
with a live busbar.
I would not cut the spare off - you may need to add a new breaker one
day. It's quite safe when the enclosure is on.
Tape - no. if you use the way, your prong is now covered in sticky stuff.
Heatshrink - tricky unless you do it before you install the bar.
A bit of heavy sleeve that is a tightish fit would be OK if you really
On 12/04/2015 13:38, firstname.lastname@example.org wrote:
Problem is (and what's thrown me), is the spare pin in the bus-bar.
What makes you think the bus-bar can't be removed and hacksawed on a bench.
That way your conductive swarf could be kept away from the box.
It is also possible to file off sharp corners.
Your tinsnips are better than mine!
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