"RichardS" noaccess@invalid wrote in message
.. .

"Christian McArdle" wrote in
message
. net...
In my flat I've discovered that each end of the two socket ring
mains
go back to separate MCBs.

Yes. The current wiring is extremely dangerous and could easily
lead to a
fire. You should fix the problem immediately. I think the whole
installation
should be thoroughly tested. With one absolute shocker like that,
there
could be many other disturbing irregularities.


does this mean that the circuits are effectively protected at (a
chilling)
64A at the moment, or is the effect not quite that simple and
liable to be
indeterminate?

I think that would only be correct if the load on the circuit was
balenced e.g. at the mid point of the ring. If you put the 32A load
within a few mm of one MCB I don't think you could draw much above
32A (at least not for long) before the 32A MCB trips but this is
still above what the cables rated at since most of the current would
be travelling down the shorter (lower resistance) leg. In summary
your protecting the cable at 32A but the circuit between 32&64 A
depending on where the load is.

HTH

Jim

Jim

--
Richard Sampson

email me at
richard at olifant d-ot co do-t uk