My Garden workshop is wired , 2 x 20a rings, 1 x 6a light, protected by
48amp rated rcd. the rings supply a 2kw rad and a computer desk with
periferals. The power is fed from a 32a mcb on my main house
distribution board .
Recently i lost power in the workshop, however there was no tripping of
any protective devices. I subsequently tripped and reset the mcb and
the rcd in the workshop and the power was restored . Intriqued with
this i isolated all the conductors from the mcb(house) and carried out
some insulation resistance checks and open/closed mcb operation checks
which were all fine .
However when i connect the main connector back to the mcb but leave it
switched off and carry out the same checks the open circuit
characteristic no longer exists when the 20 ring mcb are switched off.
Closed the resistance is .2 ohms but when opened the resistance is 56
ohms where i had previously had open circuit , ?????????????????? The
earth for the workshop is taken from the main house distrubution earth
..
I have reconnected everything in the workshop and have power available
with heavy load with no problems.
Whats going on.