Why do circuit breakers go up for on and down for off?

Not here.

The neutral is grounded (to rods inserted in the mud) at the substation, and at the homes we have to insert a different rod for earth, in our mud, and is never joined to neutral.

When I first read the comment in this thread, I was thinking service disconnects.

I can't think of any wall mount service disconnects that don't have up as on and down as off.

The only thing I've seen is not wall mounted and is instead on tap boxes for bus ways. Most of those are the up / on & down / off, but some are side to side, usually on the bottom of such tap boxes.

Disassemble a house fan, and you will see one such reverse bolt, and understand why they exist :-)

Stay away from vintage Chrysler Corporation vehicles. The lug nuts on the right were left handed thread. Some other manufacturers also did the same.

The theory was the wheel rotation would loosen a right handed fastener. It was valid for the Rudge-Whitworth style center-lock hubs popular on old British sports cars with wire wheels but overkill for modern wheels.

You're going back a long way there, they were Penny and Giles quadrant faders, and they worked backwards because they were quarter-circles on edge, and someone seated at the desk couldn't see the furthest markings very well. So maximum volume was closest to the operator, where individual dB markings were easy to read.

I worked in Television Centre about 45 years ago and never saw one there, though I think they still existed at the Wood Norton training centre. The BBC couldn't afford to build its own equipment by that time, they were buying from the big mixer manufacturers, who were using the familiar flat slider potentiometers.

That's something I had trouble understanding.

They are at the same voltage when no current is being drawn. When current is being drawn, there will be a voltage drop on the current-carrying wire.

No need for the 100mA RCD, just put RCBOs on all the circuits that need

I currently have only one MCB left - which powers the alarm box and TV multiswitch and as these are both under the floor and not likely to be drilled into, there's no rush to change it to an RCBO.

I have installed an unneeded RCBO for the EV charger - a double pole MCB is sufficient, as the charger includes its own RCD protection. However, my consumer unit is a Crabtree Starbreaker and double pole MCBs take up two slots, while an RCBO, with full off isolation for both L&N, takes up only a single slot. Worst case, there is no discrimination, so either end may trip, but that doesn't really matter.

No. There is a figure that government, councils, industries use to work out whether to spend on improved safety or not. If it will cost many millions to save each life, then simply, the money is better spent elsewhere, where it can have more effect.

Some circuit breakers are not certified for horizontal or inverted installation though. Probably absolutely fine for that use, but not tested for it.

You've not got a 3-phase supply have you? They often use three vertical rails, one for each phase, with breakers mounted sideways, to supply single phase circuits.

Couldn't we sell you for spare parts?

Telephone vs calculator keypad layout. How did that happen?

When I was about 14, I took apart a broken pocket watch.

A couple of the screws were in so tight, I twisted the heads off trying to get them out. Years later I found out they were left-handed screws and I was twisting the wrong way. Every second screw in a gear train was left-handed, so, I guess, the friction against the gear wouldn't loosen the screw.

But a couple of the screws I did get out hit the glass top of the desk and bounced on the floor where they fell into cracks between the hardwood floor boards and I never found them anyway. Don't work on glass. At least it was a very cheap watch.

In Philosopher's situation, there were 3 current paths: Hot---1---device-----+-2--neutral-----ground | +-3---ground (view above in an ascii font)

In words: current flows on the hot wire (path1), through the device and then on two separate paths to ground. One path (path2) is on the neutral wire to the panel to ground. The other path (path 3) is through the short circuit (between neutral and ground) in the workshop.

The RCD compares current flow on the hot wire to current flow on the neutral. If there is a difference of flow in low milliamps (5ma in the US, not sure in the UK but maybe 20 ma) the RCD (or GFI in the US) trips. With the short to ground in the workshop a large amount of the current that would normally be on the neutral wire goes to ground, meaning the current on the neutral wire that the RCD "sees" is a lot lower than the current on the hot wire, so the RCD trips.

In addition, some (all?) RCDs may contain circuitry to detect a ground to neutral short even with no device connected, and trip if such a short exists.

Ed

I never realized they were. I'm left handed and never use the keypad on the right of the keyboard nor do I use calculators often enough to think about it.

I do remember Ma Bell's kiosk at the '64 World's Fair where they were convincing the public how much better touch tone was than rotary.

The lights are (and I might have got the order upside down)

red yellow green yellow

Red = Stop Green = Go Single Yellow = next signal is red, so prepare to stop at it Double Yellow = next but one signal is red (used where linespeed is higher and stopping distances are greater than spacing of signal posts)

Apart form other considerations, a switch is more likely to be accidentally pushed down than up, and we want such accidents to be as safe as possible.

Sylvia.

Why do "slow up" and "slow down" mean the same thing? Why is there "speed up" but no "speed down"?

Nope, they are all WAY past their useby date.