I'm converting my garage to a small woodworking
workshop. I need to install a CU in the workshop
and run a cable from the house CU. As it happens
the house CU will be replaced at the same time.
I know how to do the cable calc, but I'm struggling
with two aspects. One is understanding what I use
for Ib (Design Current), the other is to do with
Type B / Type C MCBs.

Design current first.
-----------------------
This is design current of the workshop. I'm not
using diversity because I am very clear about
what the max current will be and that it will occur.
What I don't know, is what to do about motor
startup currents. Do I have to take them into
account for Ib? Some of the machines
(Eg.. 3Kw Hammer Sawtable) have soft start
so I imagine the startup currents are handled by
the electronics in the machine. Others, like the
2.2Kw Axminster ADE4000 Dust Extractor
don't have soft start. Axminster have told me
that I should double the running current and add
another 15% in cold weather.

MCBs
-------
My thinking is that I may need Type C MCBs in
the workshop CU. I am really gozzy on the
differences/benefits/requirements re Type B and
Type C. My only understanding (apart from the
various graphs/charts in the Regs) is that the Type C
is less sensitive to startup currents. How do I
determine if Type C MCBs are needed? Also, if I
have Type Cs in the workshop, does that mean that
I must have a Type C for this circuit in the house CU.
If so I think I might have to run a separate (larger)
CPC to satisfy the Shock Protection requirements.

Thoughts?

Oh - and BTW - I know about Part P - before we go
down that route!!! :-)

Many thanks,
Roy