DPST? 2 switch / 3 circuits (2 independent, 1 shared)

[BHI]

Is this the right/best way?! Simplified diagram:

Untitled

• BHI
• 31 Jan 2012
• 1

Problem: Two light switches will operate three light circuits - the middle one to come on with either switch.

Context: Living / dining area with downlights in a boxy "8" shape - ie. all around the outside of the ceiling, and then a joining row in the centre. Want either side of (and including) middle row to be able to be lit independently. Middle row must be lit with either and/or both switches.

Questions:

1. Do DPST domestic light switches exist?

2. What are the wiring / load / etc implications of none / one / both switches being on?

3. Any obvious alternatives? (other than not doing it!)

4. Is there such a thing as a "one-way valve" so the middle row can be wired in to two SPST switches (without also lighting the other circuit too)?

Many thanks!

 

[OwainDIYer]

1. Do DPST domestic light switches exist?

DP switches certainly exist but usually in 20A versions - whether that will be a close enough cosmetic match to a 6A lightswitch is up to you. Or check gridswitch ranges.

2. What are the wiring / load / etc implications of none / one / both switches being on?

The total load must be within the capacity of the switch and circuit.

3. Any obvious alternatives? (other than not doing it!)

3 separate switches

4. Is there such a thing as a "one-way valve" so the middle row can be wired in to two SPST switches (without also lighting the other circuit too)?

relays
programmed light controls such as X10, crestron, etc[/b]

 

[BHI]

Thanks Owain.

Had considered the 3-switch option, but just wondered if there was a neater solution.

Happy to go down the Crabtree / MK / Varilight grid route to incorporate other light switches too - just can't find a DPST version though...

What do you mean by the 20A version? Do they look much different? Do you have a link?

Many thanks again!

 

[EFLImpudence]

Other than rather complicated designs

As has been suggested - grid switches.
http://www.tlc-direct.co.uk/Products/MKK4896.html

3. Three gang switch ???

 

[riveralt]

Potentially 1 Kw of lights on at the same time - toastie......
Best option as suggested is a three gang switch with each 'circuit' wired to one of the gangs.

 

[BHI]

Perfect - thanks... Thought those double-pole 1-way switches were usually for isolating the live and neutral, but like your approach. Are there any issues with both of the switched lives of the middle row being connected?

Point noted about the load. Had planned to use LED lamps, although realistically until they improve / come down in price, think they'll be CFL GU10s. Still up around 242W though (22 x 11W) all on...

So otherwise, all okay? Would rather be set right now than sizzle the house!

 

[ban-all-sheds]

Is this the right/best way?! Simplified diagram:

Untitled

• BHI
• 31 Jan 2012
• 1

I count 22 lights.

Surely unless you've done something barking mad, like choosing lights that are useless, that must be your entire house.

Why on earth do you want your entire house lighting on just two switches - won't that be remarkably inconvenient?

 

[ban-all-sheds]

Ah - just noticed this:

Context: Living / dining area with downlights in a boxy "8" shape - ie. all around the outside of the ceiling, and then a joining row in the centre.

It seems you have done something barking mad.

 

[BHI]

In the process of a complete property renovation and aside from moving a few switches / adding a couple of sockets, have pretty much left the electrics alone (limited scope due to concrete ground floor - ie, all ground floor sockets appear to be spurs off ring final main on first floor). However, wanted to make a bit of a "wow" impact in the lounge / dining area with two adjacent "tray" ceilings with downlighters... Hopefully not "wow" in a kind of Guyfawkes Night bonfire way though!

So individually, the lights don't need to be amazingly bright in themselves, as it's the overall effect we're after.

What would your take / solution be? All advice welcome... (I know, like "don't"!)

 

[ricicle]

You have shown the lights wired in series which tells me that you don't know enough about lighting circuits to be attempting this.

Try here for starters:-

//www.diynot.com/wiki/electrics:lighting

 

[riveralt]

You have shown the lights wired in series which tells me that you don't know enough about lighting circuits to be attempting this.

Try here for starters:-

//www.diynot.com/wiki/electrics:lighting

Its fair to say to the OP that his design and number of downlights is mad but in relation to his diagram he did say..

Is this the right/best way?! Simplified diagram:

 

[BHI]

No, not in series - more a lack of my artistic ability with SmartDraw to show the junction boxes, neutral and CPC too... The diagram only shows live / switched live for clarity, but I appreciate your comment - the way I've used the icons does make it look like series, but that wasn't my intention...

 

[riveralt]

No, not in series - more a lack of my artistic ability with SmartDraw to show the junction boxes, neutral and CPC too... The diagram only shows live / switched live for clarity, but I appreciate your comment!

Just remember though that should you go down the road of LED's as you suggested then they sometimes come with constant current drivers and then you will have to wire them in series.

 

[BHI]

Not sure that LED lamps are within budget just yet...

Dare I ask what folk recommend as the usual spacing for CFL downlights to cast sufficient light? I'd been working on assumption that 11W CFL is (when eventually warmed up) equivalent to 50W incandescent?

Or might even use 8W CFLs... Looking more for the "mood lighting" effect than daylight dazzle!

Appreciate everyone's help - genuine thanks.

 

[riveralt]

Not sure that LED lamps are within budget just yet...

Dare I ask what folk recommend as the usual spacing for CFL downlights to cast sufficient light? I'd been working on assumption that 11W CFL is (when eventually warmed up) equivalent to 50W incandescent?

Or might even use 8W CFLs... Looking more for the "mood lighting" effect than daylight dazzle!

Appreciate everyone's help - genuine thanks.

http://www.dusklights.co.uk/technical-advice/fitting-downlights.html#how many downlight