On 23/04/2017 19:00, charles wrote:
In article ,
John Rumm wrote:
On 23/04/2017 07:59, Jeff Layman wrote:
On 23/04/17 03:18, John Rumm wrote:

Its not usually a problem with lighting circuits since the cable is
significantly over specified in the first place.

Do you know if this is a hangover from the 20s and 30s when "lighting"
circuits were often used for devices with a moderate power consumption?

Not so much that, more a case of 1mm^2 is the smallest T&E used and
anything smaller would start to get a bit fragile, not to mention the
resistance would creep up - hence more brightness variation and longer
disconnect times in the event of a fault.

Also there is a (not often used) standard lighting circuit protected
with a 10A MCB, and that is somewhat closer to the 1mm^2 11.5A "in
conduit" rating for the cable.

I can most certainly remember in the 50s when my mother used to iron by
plugging it (bayonet plug) into a two-way connector in the ceiling
light. As far as I remember, the only time the 15 amp wall socket was
used was for a 2 or 3-bar heater.

Indeed... A reflection of reality that in many properties, the only
electrical provision installed was for lighting. Sockets etc came later.

Our first house, wired in 1947, had 4 "power points"; one in each bedroom
and one in the kitchen. There was a 2A socket off the lighting circuit in
the living room.


That would have been a posh install:-)

--
Adam