Consumer unit Œ

Not sure, but at a guess I would say, when they stopped using fuses and used MCB's!

Sparks...

I think when we moved away from separate main switches, switch-fuses and splitter fuseboxes (usually in wood with glazed fronts, or cast iron) to a single unit incorporating main switch and all fuses.

Such a unit (also incorporating a cooker control switch) was marketed as a "Kitchen Control Unit" for new post-war housing in 1947, but I don't see a reference to "consumer unit" as such.

Owain

Long before that. Circa 1947 would be my guess, when BS 1363 and the ring circuit first came along. A consumer unit is the combination of a main switch (or main switch-fuse, as they usually were, pre-war) and a fuse box. Double-pole fusing was also the norm before WW2, leading to all kinds of dangers.

DP fusing necessary because the supply at that time wasn't reliably tied to earth.

AIUI countries like France use DP MCBs for this reason even now.

Owain

It changed when fuse boxes were combined with the main switch.

There was an article in a recent /Wiring Matters/ [1] on the origins of the BS 1363 and ring circuits, etc. This focusses on a report [2] published in 1944 which established much of the basis for wiring practices which are still with us sixty years later. The article refers to the report "mak[ing] proposals for single-pole fusing, a novel compact design of consumer control unit, the cooker control unit [etc., etc.]"

That would put the first use of the term "consumer (control) unit" at somewhere between 1942 (when the work started) and 1944.

At least in a technical context. As far as the average user is concerned, it changed when MCBs and RCDs replaced the old "fuse box".

Christian.

Giving twice the chance of the wrong one blowing? ;-)

Could have dated from DC days, too.

Fuse Boxes did become Consumer Units but I have no idea when ....Possibly when an alternative to fuses was found ....Circuit Breakers .

Stuart

No, I think it was when one box with multiple fuses of different values replaced a collection of miscellaneous switch fuses - one for lighting, one for power, on for immersion etc. Part of the reason for the latter is that in the early days you paid different rates for lighting and power so had two meters.

I have never heard a non-electrician refer to any unit containing only fuses (rather than MCBs) as a consumer unit. It is invariably a fuse box, whether it contains one fuse or ten fuses, whether it has an isolator switch or not. IME, DIN rail = consumer unit, Wylex/MEM = fuse box.

Christian.