American electrics

Do you mean ring circuits get scaled up?

No, because of the magnetic fields generated due to the ring configuration.

Only radial circuits get scaled up.

HTH

You trying to say people didn't ever use the wrong fuse wire in radial circuits?

Or saying that nobody would ever change an MCB that kept tripping in an overloaded radial to an unsuitable one in a workshop, etc?

I've got news for you...

machine?

spur

No, there is no need for one socket per radial, what *is required* are the MCB's (which is far more difficult to circumvent), in these days of low wattage appliances you could easily have two if not three sockets per radial without load problems - how many people use more than one Kew fire in a room anyway (any such load would have extra provision made even now in many homes, even with ring circuits) ?...

It's not just about fuses blowing, it people using the wrong fuse, for example protecting a table lamp with a 13A fuse, when the lamp should / could be on a lighting circuit. What I'm trying to get over is that there is (IMO) the need to remove the user from the direct supervision of the appliances final protection. Sealed MCB's / RCD's back at a distro' board allows that, this was not an option back in the 1940/50's.

You seem to be happy that someone can protect a single 40W light bulb stand and meters of such rated cable @ 13A (or more, if the *user* wishes and does something totally idiotic) with little or no thought - far enough...

average

room.

Or any part of the house were large electrical fires are, or might, be used - in one of our past houses we had 3 rings (one on each floor), the kitchen was on a separate supply, such was the size of each room if the CH failed and electric heating had to be used each room would have needed a 3Kw fire and with four or more rooms on each of the two lower floors...

Usually out to garages and back according to your design guide

Oh - I do. And given that your 'knowledge' of anything comes from adverts and websites, surely a little Googling will say so too?

You do know how to Google?

It certainly does. When will you stop?

radial

No, I'm not saying that, It would be crazy to (go back and) use wire fuses a the fix circuit protection on radial circuits - just as it's with ring circuits today, MCB'S are the way things are going.

But that requires some thought, anyone from a child to an OAP can, has and will replace a BS1363 type plug fuse with the wrong rating at some point - accidentally or intentionally.

Yes, and I can really see a 80 year old 'Granny Mabble' doing that, her replacing a 3A fuse with a 13A one is almost a certain bet at somewhere....

But that is exactly what happens with unfused plugs. And unless you are going to return to the days of 5A and 15A sockets (and a plethora of adapters, often unfused) *all* the socket circuit MBCs have to be adequate for the heaviest load eg 3kW heater so the circuit cannot be protected at a lower value. This is exactly what happens in countries with unfused plugs - table lamps on 16A or 20A circuits.

Owain

Please, don't tell him. He's bad enough with back issues of Practical Plumbing for Merchants' Messenger Boys.

Owain

The first ring mains date back to ca.1947, when the Wylex (?) plugs were introduced: a central round earth pin, with the phase & neutral pins being rectangular, in the horizontal plane slightly above the centre of the earth pin.

By the early 1950s, ring mains and our present-day familiar 13A plugs were standard (and mandated?) for all new construction.

incoherent babble always emerges.

In 1953, my parents moved into a Officers' Married Quarter at RAF Little Rissington; this was not brand new, but had only had one previous tenant since being built, under MPBW[1] direction, in 1951. This house had 13A "square pin" plugs throughout, which fascinated me as an eight-year-old, since I'd only hitherto seen two- or three- ROUND pin sockets, in two sizes (5A & 15A).

In 1956, we moved into a C16th cottage belonging to a family friend; this had been recently renovated after the death of the aged relative that had occupied it, and 13A sockets and ring mains were standard. So the old systems were definitely dying out by the mid-50s, if not earlier.

In 1949, Glasgow, Greenock, Motherwell, Merthyr, Redcar, and no doubt many other places had 250 Vac (and often Vdc)

Edinburgh had 230 / 460 Vdc and 115 / 230 / 400 Vac

Leeds coulnd't make its mind up between 200, 230, 346 or 400 Vac. Colchester and Stafford were still on 210 / 420 Vdc.

Very few places wree on 240/415 Vac.

(Practical Electrical Wiring and Contracting, E H Freeman MIEE, London: Odhams Press)

Owain

You're obscessed with a non-issue. Attempting to "fix" such non-issues can't bring any real benefits, but can introduce real problems. If you want to present a valid argument which can be taken seriously, you need to identify real problems that actually matter.

Murphy's Laws says "If can happen, it will happen". How do you protect from all eventualities?

You are going to say, you cannot. Then it is a matter of reducing the probabilities of Murphy's Law being invoked.