Replacement wall light switches

Doubtless a daft question, but ...

I want to replace some of our ordinary white wall light switches, some one way and some (landing light) two way.

Seen a box of ten two way that would suit. Presumably there would be no problem replacing a one way switch with two way, and just ignoring the extra terminals?

Reply to
News
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Bod wrote in news: snipped-for-privacy@mid.individual.net:

No problem.

Reply to
DerbyBorn

I've always replaced/fitted 2-way as standard. The difference in price is pennies and if a change needs a 2-way in the future it's already there.

Reply to
PeterC

Correct. A 1 way switch is simply a 2 way switch without the extra terminal and contact!

Reply to
Tim Watts

That's correct.

Reply to
John Rumm

Thank you all. Box of ten duly ordered. I was more worried about a sharp intake of breath and quotes from Section something of some rules and regulations, but apparently not :-)

Reply to
News

Yes, as others have said there's no problem.

It's so common that you'll probably find that the manufacturer has already marked the appropriate terminal to use for one way so that you don't have to turn the switch upside down to get the on and off positions right way up.

Reply to
Mike Clarke

In message , Mike Clarke writes

Don't you just *hate* upside down light switches? Even two ways are annoying because one is always upside down :-)

Reply to
News

In message , News writes

Not really.

Probably for that reason. We have at least 3 sets of two way switches here.

Though a friend of ours has a switch for the light in a toilet upside down for some reason (been like it as long as we have known them, so about 10 years). I'm tempted to swap it round one day to se if it annoys them,.

Reply to
Chris French

Anyone who's lived for a few decades in N. America knows that 'on' is up !

Reply to
Windmill

Correct, but on the other hand their sockets can be sideways or even upside down and nobody notices.

Our sockets must be earth-pin up for some reason, but if you look at many UK type wall-warts made in the Far East, the orientation of the label suggests the Chinese think our sockets are mounted earth pin down.

Reply to
Graham.

Not necessarily. Lots of the meeting rooms at work have them the other way up, because they're so close to the floor.

Reply to
Huge

Exactly right! I doubt the variation between top or bottom cord entry on UK wallwarts has anything to do with plug orientation so much as the percieved location for the socket where close to the floor or worktop makes the top entry the more useful option and vice versa for higher socket locations or where the lead is expected to be trailed more than a couple of metres over the floor to whatever it's intended to power.

In this case, there's no "Wrong Way" in regard of top or bottom cord entry.

Reply to
Johnny B Good

I think most of us in the UK are well aware of the US light switch convention. I'm sure there was a good reason for arranging that heavy duty switches and circuit breakers used to control power hungry appliances and industrial machinery use the downward direction to 'Kill The Power' on the basis that, for safety reasons of one sort or another, it was easier and swifter to shut off power when the user could literally hang his weight off of the switch lever and drag it into the off state making good use of their body weight to help accelerate the process (in today's US society, the obesity epidemic has proved to have at least one plus point in its favour :-).

However, the on/off direction of domestic switches, particularly light switches is simply a matter of convention which is most likely tied to an analogue of an older, simple to visualise, method of flow control such as the raising of a sluice gate to initiate a flow of water (the up is on convention) versus the UK convention where up is analogous to the raising of a road bridge to stop the flow of traffic (or, even older, the raising of a drawbridge to stop the ingress of soldiers from an attacking siege army). In short, the UK convention is based on the concept of "Raising a Barrier" to shut off the flow of electrons, thereby switching the light off whilst the yanks think of the process as akin to dropping a sluice gate to do likewise.

It's just a convention as to which direction has become the entirely arbitrary choice for the on and off positions of switches in common domestic usage. As such, there's little point in arguing which of the two conventions "is the right one", they're both equally right (or wrong) depending on which of the two equally valid conventions came to be in common usage in the region where you happened to be born and raised.

Reply to
Johnny B Good

You've come up with some arguably convincing reasons why the conventions should be the way they are. But as you imply? it's all relative.

Reply to
Windmill

====snip====

That was my point. There's no absolute "Truth" in either convention at least as far as it concerns switching ac mains power[1] to lights and domestic appliances. I was merely pointing out the futility of arguing the pros and cons of which way round lighting and appliance switches should be configured in the domestic setting for their on/off function. At this level, the convention becomes entirely arbitrary.

When it came to heavy duty industrial switchgear (almost invariably circuit breakers), particularly of the DC kind, the problems of arcing on opening such switches most likely did figure into the decision as to which way was "Up" (off or on). Plus, as the yanks will frequently point out as a justification, the down is off convention for seriously heavy duty switchgear is a boon when it comes to emergency shutdowns where the operator's own body weight can lend extra impetus to a recalcitrant circuit breaker that may already demand a modicum of brute force for its operation under normal circumstances.

It's been quite a while since I last saw any heavy duty industrial circuit breakers but ISTR that the convention, worldwide, is down for off [2] (putting aside the issue of heavy duty rotary lever operated switches where ISTR the convention is lever position for off being at right angles to the direction of the cable entry points, or perceived flow direction of the supply current).

When it came to domestic switches designed for frequent operation 'at the flick of a finger', the yanks, not unreasonably, chose to use the convention derived from industrial practice.

For some reason, here in the UK, this was turned on its head and UP became the off position, presumably based on the analogy of 'raising a barrier' to shut off the current. Perhaps this convention was deliberately chosen to emphasise the safety of modern domestic appliances and lighting which could now be controlled 'at the flick of a (finger operated) switch' in which the direction of the switch lever position for off was no longer related to any issues of safety and was now merely an arbitrary choice.

[1] The issue of arcing in switches (and, for that matter, fuses) that was so troublesome with domestic DC mains, virtually vanished with the introduction of AC mains supplies allowing for much shorter switch contact air gaps (and fuse wire lengths), permitting the use of simpler and more compact switch designs that could be readily operated at the flick of a finger.

The 100/120 times a second zero crossings of supply current meant that the unavoidable arcing when opening a switch would be limited in duration to no longer than half a cycle of the mains frequency. This eliminated the need for a rapid toggle action to seperate the contacts by half an inch or more.

A modern light switch is little better than a cheap "Two strips of brass bell push switch" in its design concept as a consequence of the universal use of AC mains for domestic supplies. Furthermore, the arcing of AC current is far less destructive of switch contacts than is the case with DC current.

The pip and crater erosion effect on the contacts is suppressed due to the removal, statistically, of a net DC current flow. Indeed the transfer of material from one contact to the other and back again reduces the net loss of contact material significantly, extending the life of the contacts compared to a DC switch subjected to the same levels of arcing current energy.

[2] Even the very tiny cousins used in domestic CUs use the down is off convention. It makes a lot of sense to stick to such a safety related convention originating with heavy duty industrial circuit breakers that required considerably more effort to operate than the mere flick of a finger. In the UK, it helps emphasise the fact that the user is dealing with a safety device rather than an every day control switch.
Reply to
Johnny B Good

On a different subject - is there a standard convention about hot and cold water taps - which side is hot, right or left when fitted to a sink/bath or in the case of a mono-block right or left of pillar?

Reply to
alan_m

In this house the convention when I moved in was hot on the right upstairs and hot on the left downstairs!

Reply to
Andy Burns

Generally, hot seems to be on the left, but I've found plenty the other way round

Reply to
Chris French

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