"Woland" wrote in message
...
Now the problem: in 2000 [...] (there were no split units at the time).

Oh yes there were.

Was just a hypothesis

A 49Amp MAX armoured cable (should be 2.5mm^2, not certain but I'm
certain it's 49 Amp MAX) which is some 40 metres long goes from the
RCD-protected CU straight into the summer house to provide power.

With that length of run the effective current rating of your submain
will be limited by voltage drop and not by the current rating of the
cable.

You might
findhttp://wiki.diyfaq.org.uk/index.php?title=Taking_electricity_outside
useful.

I had read that and I was expecting a serious voltage drop (no load
reading doesn't count, obviously).
So I set up the usual easy measurement with a 2 KW load (circular saw
+ lights + other resistive loads) and... strange but true no drop!

Experiment repeated several time... same result. I am actually curious
to find out why I'm not withnessing any voltage drop... maybe the load
is too small?

You're obviously using special zero-ohm oxygen-free speaker cable.
Supplier/price?