Which is live wire?

[333rocky333]

Thanks john, im now with you, i think, your talking more regarding the direction of the in and outs of each switch, whereas i was discounting the actual internal switching positions

and meaning regardless of whether flowing via the switch or through the link wiring
And even if you took the guts out of the mechanism.

Change to the alternate wiring method and which terminals are live feeds to the switch and which are live outputs depends entirely upon which way round the switches are set and changes as the switches are moved.

The Live terminal and the switchline terminal never ever changes over except with an intermediate

But i agree on your last point , also as you showed earlier in normal two wire strappers , the switchline is always found in the "common" terminal and the Live feed would have to toggle between L1 and L2
We all know its irevolant on 1 way switching most of the time, anyway
Goodnight

 

[JohnW2]

Thanks john, im now with you, i think, your talking more regarding the direction of the in and outs of each switch

Well, yes - but that's because of the context - the bizzare lengthy discussion (not involving me!) about whether a terminal marked 'common' should be used as the live or switched live in '1-way' switching!!

Kind Regards, John.

 

[Paul_C]

We all know its irevolant on 1 way switching most of the time, anyway

And that was the point which started this whole debate, the assertion made earlier in the thread that putting the live feed to C and the light to L1 is the "correct" way to do it, implying that the opposite way round is therefore "wrong." As you've just acknowledged, for a simple 1-way light switch it makes no difference which way round the connections are made, so there is no wrong way round.

 

[333rocky333]

We all know its irevolant on 1 way switching most of the time, anyway

And that was the point which started this whole debate, the assertion made earlier in the thread that putting the live feed to C and the light to L1 is the "correct" way to do it, implying that the opposite way round is therefore "wrong." As you've just acknowledged, for a simple 1-way light switch it makes no difference which way round the connections are made, so there is no wrong way round.

Actually the point i was making is-
When the OP gets his new dimmer that is assuming that is not what he is already talking about now.
If he has L1 and a wavy line marking
What cable is he most likely to bung in the L1 terminal.
The one he removes from the existing" L1" terminal or the one he removes from the "common"
My response was to someone earlier saying that manufacturers instructions were to be followed, yet days earlier stated to connect a dimmer in reverse, possibly against the manufacturers instructions.

I will continue putting the feed into the "L" terminal thank you, the same as any other connection or appliance marked "L"

 

[ban-all-sheds]

My response was to someone earlier saying that manufacturers instructions were to be followed, yet days earlier stated to connect a dimmer in reverse, possibly against the manufacturers instructions.

Connecting it in reverse.

An interesting concept with AC...

I will continue putting the feed into the "L" terminal thank you, the same as any other connection or appliance marked "L"

Even when the MIs tell you not to?

 

[JohnW2]

My response was to someone earlier saying that manufacturers instructions were to be followed, yet days earlier stated to connect a dimmer in reverse, possibly against the manufacturers instructions.

Connecting it in reverse. An interesting concept with AC...

I think it (non-reversibility) may be a perfectly valid concept with some two-terminal (no neutral) dimmers.

Kind Regards, John.

 

[EFLImpudence]

When the OP gets his new dimmer

The dimmer had nothing to do with the OP.

 

[sparkwright]

I tend to use Com for the perm live and L1 (or L2 where applicable) for switched live.

I only do this just to keep things 'uniform', and because many others do it this way.

Some DIMMERS specify the terminal they call Com is for the switched live. But that's dimmers, and their manufacturers instructions - so quite irrelevent.

On a similar note, it is the convention in a three plate ceiling rose to connect the switch cable brown/red to perm live; and the blue/black to the switch live. Very rarely do you see it the other way round.

 

[JohnW2]

When the OP gets his new dimmer

The dimmer had nothing to do with the OP.

As was pointed out to me a couple of pages back, it probably does if you look at the other thread!

Kind Regards, John.

 

[333rocky333]

Maybe in other switching examples ie to have an indicator to show when its off, then common would need to be used.

¿Que?

Sometimes an indicator is mounted next to a 2way keyswich to show when power is switched off to emergency lights in test mode, therefore the feed would need to go in "common" and im sure theres other applications,

My response was to someone earlier saying that manufacturers instructions were to be followed, yet days earlier stated to connect a dimmer in reverse, possibly against the manufacturers instructions.

Connecting it in reverse.

An interesting concept with AC...

Well sometimes we use dimmers and switches with an indicater on the output so yes, in some cases it would matter

I will continue putting the feed into the "L" terminal thank you, the same as any other connection or appliance marked "L"

Even when the MIs tell you not to?

Yet to see one that specifically says put the feed in common, or even any supplied with a 1 way switch, yet seen plenty of dimmers that have said connect either way, or with a drawing showing to specifically use the L terminal

 

[333rocky333]

When the OP gets his new dimmer

The dimmer had nothing to do with the OP.

And neither did he ask how to connect anything, what i was querying was

That the standard method used to install a one way light switch is to connect the permanent live to the com terminal and it is also good practice.
If we take a look at BS7671:2008
134.1.1
This bit becomes relevant:

But you felt the need to say below, when its a fact a lot of switches no longer use "common" as shown on many posts on this forum

Nowadays the word common is being phased out.

You're thinking of when it's paired with sense.

 

[ban-all-sheds]

I think it (non-reversibility) may be a perfectly valid concept with some two-terminal (no neutral) dimmers.

Well sometimes we use dimmers and switches with an indicater on the output so yes, in some cases it would matter

Can't see it myself, but there ya go.

 

[333rocky333]

Changed my mind, see what your saying

 

[securespark]

"Common" has nothing to do directly with how the circuit itself is wired; it refers only to the fact that the terminal so marked is the one which can be connected to either one of the other terminals depending upon the position of the switch. Something like a 10-way rotary switch also has a common terminal - The one which can be connected to any one of the ten other terminals depending upon the switch position. Whether there are ten separate feeds which can be connected to provide an output on the common terminal or whether there's a feed to the common which can provide an output on any one of the ten other terminals depends entirely upon the application at hand.

Exactly - you just beat me to that analogy. I was 'brought up' on N-way rotary switches, and the 'rotor' terminal was always called "common" - and I presume that's how the term came to be used with 2-way light switches - i.e. a term relating to the construction/function of the switch, not anything to do with what circuitry was connected.

Also, I'm not even sure that the 'L' of 'L1' and 'L2' originated as having anything to do with live/line. I have some old rusty cast iron changeover switches (not in service ) in which the terminals are labelled 'Common', 'Load 1' and 'Load 2' - so I just wonder whether that might possibly have been how 'L1' and 'L2' originated?

Kind Regards, John.

I'd just like to leap on this bandwagen if I may...

I was actually going to post similar, but Paul, then John beat me to it.

While at college back in the days when Wham first hit the charts (young uns look this up!), I learnt that the "COMMON" terminal was so-named because it was common to the the others: ie the other terminals link to it. Think about it: in one position, the common links up with L1 and in the other to L2.

 

[securespark]