Smart switch 1 gang 1 way

[Tandoori]

Hi, i’ve been trying to buy a smart switch 1 gang 1 way but i opened my conventional wall switch and i only have 1 red wire(Live Old UK) 1 black wire(Neutral Old UK) and 1 Green/Yellow(Earth Old UK) but the smart switches have another wire the Load wire, now i’m confused how does this work?

 

[SJD]

The black wire is a switched live (L). There is no N at this switch - which is pretty common way of wiring, especially for older houses.

 

[Tandoori]

The black wire is a switched live (L). There is no N at this switch - which is pretty common way of wiring, especially for older houses.

So would a “No neutral required” smart switch work in replacing the existing switch? Also thank you for explaining this, i had been confused the whole day

 

[Avo Mk8]

Yes - buy a smart switch that does not require a neutral.
To work they require a small current to flow through the light fitting all the time. With filament bulbs this is no problem, but with some LED bulbs this can lead to the bulb glowing dimly, or flashing. The workaround is fitting a capacitor/snubber across the bulb, and I believe some no-neutral smart switches provide this component along with their switch.
So it is possible to fit a smart switch, but it's a little more hassle than when you have a neutral (which, as said above, most people in older houses do not have!)

 

[Knights]

Yes - buy a smart switch that does not require a neutral.
To work they require a small current to flow through the light fitting all the time. With filament bulbs this is no problem, but with some LED bulbs this can lead to the bulb glowing dimly, or flashing. The workaround is fitting a capacitor/snubber across the bulb, and I believe some no-neutral smart switches provide this component along with their switch.
So it is possible to fit a smart switch, but it's a little more hassle than when you have a neutral (which, as said above, most people in older houses do not have!)

Apologies for reviving an old thread, but I'm encountering the same issue as the OP. I'm trying to wire a FST24 timer switch to control outdoor lights, and my current setup is as follows:

Light Switch Wiring: Blue and Brown wires are connected to L1 and Com.

The new timer switch requires connections for the supply and load.

I’ve run a new supply line from the junction box to the switch, and connected this to the supply terminals on the new switch (using Brown and Blue wires). Same breaker.

I then connected the existing Brown and Blue wire from the old switch to the LOAD terminals on the new switch. However, it's not functioning. It shows there's power to the new switch, but the outdoor lights don't come on? I suspect i am like the OP and getting confused regarding the switched live. Can anyone advise?

 

[Avo Mk8]

Yes, a similarity with the original post!
At your light switch, as you suspect, the cable you have there is not a live and a neutral. They are both "live" wires, one (probably the brown) is permanent live supplied from your fusebox, and the other (probably blue) is the switched live that connects to the lightbulb. So to mimic the original light switch with the timer, the light switch brown would go to "L in" and light switch blue to "L out" of the timer.
But then you would still need a neutral to "N in"
It sounds as if the blue you have found in the junction box is actually a neutral, as the timer has come to life.

The next important point is that you need to be sure the junction box you have connected to is on the same house circuit as the light.

If it is, and you still have your new L and N feeding the timer, try connecting the switched live of the old light switch to "L out" of the timer. If you have a multimeter/volt pen gadget you should check the switched live to the bulb is the light switch blue wire, however your experimenting already seems to demonstrate that blue is switched live to the bulb.

If the neutral you've added isn't on that lighting circuit, and you have RCD's in your 'fusebox', you may have them tripping.

Alternatively you could do this:
Light switch brown to "L in" of the timer
Light switch blue to "L out" of the timer
Your new neutral to N in of the timer.
Your new L safely isolated.

You don't need to switch the neutral to the light, in fact you can't, as neutral is run directly to the bulb, so just ignore "N out" as not required.

 

[Knights]

Yes, a similarity with the original post!
At your light switch, as you suspect, the cable you have there is not a live and a neutral. They are both "live" wires, one (probably the brown) is permanent live supplied from your fusebox, and the other (probably blue) is the switched live that connects to the lightbulb. So to mimic the original light switch with the timer, the light switch brown would go to "L in" and light switch blue to "L out" of the timer.
But then you would still need a neutral to "N in"
It sounds as if the blue you have found in the junction box is actually a neutral, as the timer has come to life.

The next important point is that you need to be sure the junction box you have connected to is on the same house circuit as the light.

If it is, and you still have your new L and N feeding the timer, try connecting the switched live of the old light switch to "L out" of the timer. If you have a multimeter/volt pen gadget you should check the switched live to the bulb is the light switch blue wire, however your experimenting already seems to demonstrate that blue is switched live to the bulb.

If the neutral you've added isn't on that lighting circuit, and you have RCD's in your 'fusebox', you may have them tripping.

Alternatively you could do this:
Light switch brown to "L in" of the timer
Light switch blue to "L out" of the timer
Your new neutral to N in of the timer.
Your new L safely isolated.

You don't need to switch the neutral to the light, in fact you can't, as neutral is run directly to the bulb, so just ignore "N out" as not required.

Thank you very much for your reply; it's greatly appreciated! I'll give this a try tomorrow. Initially, I had the same setup as the original poster (though mine was brown and blue). However, when I realized that a neutral was needed, I ran a new supply line directly from the ground floor lights' junction box to the switch to provide both live and neutral connections. The outdoor lights are on the same circuit as the ground floor lights.

I was planning to test this. Is this what you meant? And is it okay to leave the N OUT unconnected? Thanks again! I'm just trying to get my head around this.

 

[Knights]

Oh I see, I can use either the supply brown or switch brown to the L IN? I'm understanding now!!

Thanks again. I'll give it a test tomorrow.

 

[Avo Mk8]

I was planning to test this. Is this what you meant?

Yes, exactly!

And is it okay to leave the N OUT unconnected?

Yes, the timer won't mind!
(the device you've purchased is often used as a fused spur, eg for a heater etc., and for such appliances the regulations suggest double pole switches for full safe isolation - there's no requirement for this on your lighting circuit)

Thanks again! I'm just trying to get my head around this.

I think you have

 

[Knights]

Yes, exactly!

Yes, the timer won't mind!
(the device you've purchased is often used as a fused spur, eg for a heater etc., and for such appliances the regulations suggest double pole switches for full safe isolation - there's no requirement for this on your lighting circuit)

I think you have

Thank you for helping me! I appreciate it. I'll report back. Have a good evening.

 

[Knights]

Yes, exactly!

Yes, the timer won't mind!
(the device you've purchased is often used as a fused spur, eg for a heater etc., and for such appliances the regulations suggest double pole switches for full safe isolation - there's no requirement for this on your lighting circuit)

I think you have

Everything worked perfectly—thank you so much for your guidance! I followed your advice and isolated the supply permanent live in the Wago connector. I also added a brown sleeve to the switched live. It’s much clearer now, though it was a bit confusing at first!