Extra LV LED lighting circuit in wardrobes

[festive]

Looking at adding some lights to my wardrobes

Ive purchased some of that LV LED Tape with 60leds/metre. Going to run it under relevant shelves which feeds back to a 36w 12v transformer.

Now i need some discreet door switches, naturally im going to switch the 12v rail although i guess it means ill have a 36w transformer at idle 24hours day not the greenest but..

Plan was to wire in door switch circuits in parallel for lighting circuit. Anyone recommend some light discreet door switches mechanical or reed based?

Any comments on the above and how i could improve? TIA.

 

[ericmark]

Farnell or RS Components likely to have micro switches but be aware although switching output for a transformer may be OK many switch mode power supplies have a min as well as max voltage and it may damage them switching the output.

Pedantic I know but 12 volt is extra low voltage, 230 volt is low voltage when looking for suitable switch.

 

[TicklyT]

http://www.tlc-direct.co.uk/Main_In...tches_Mini_Index/Switches_Miniture/index.html may be useful - and capable of switching mains voltage

 

[Taylortwocities]

I agree, always switch the PRIMARY of the transformer.

Many don't like being powered with an open circuit secondary, especially the electronic ones -
some will switch off if there is zero load and the only way you'll get them back on is to disconnect the 230V and then switch it back on
- which would defeat the point of the exercise!

 

[flameport]

Another reason you can't switch the 12v secondary is that most door switches (including those linked to above) are only rated to 1 or 2A maximum, and that's for AC - the DC rating will be even less.

36W would be 3A at 12v.

 

[ban-all-sheds]

naturally im going to switch the 12v rail

As others have said, that's the wrong way to do it.

Why did it seem the natural, right way to you?

 

[westie101]

I would suggest that the OP in the absence of other information, which he has now got, was working on the principle of keeping the higher voltage 230V equipment and wiring to a minimum and only having 12 wiring in the more accessible areas which would be a safer option.

 

[festive]

naturally im going to switch the 12v rail

As others have said, that's the wrong way to do it.

Why did it seem the natural, right way to you?

Hello BAS.

Give it naturally demonstrates my lack of understanding of switch mode power supplies, mine was purely a safety approach.
Additionally one would prefer to route a switched extra low voltage cable round the wardrobe than a low voltage 240v cable. Normally a thinner cable therefore easier to route and conceal (i dont like bulky white trunking in my tidy wardrobe) and as stated less risk of DEATH one assumed. There you go.

Maybe i got that wrong?

Some interesting posts here by the way thanks for the insight people, had a read up now on Switch mode PSUs and see the error of my ways, live n learn from your mistakes!

 

[TicklyT]

..... Normally a thinner cable therefore easier to route and conceal ...... Maybe i got that wrong?

The 12 Volt side actually requires larger conductors than the 240 Volt side to safely handle the higher current required to deliver the same power.

The functional insulation for ELV wiring may be thinner, but that is probably of little consequence. A good part of the insulation in cables is providing mechanical protection. That is necessary at any voltage.

The risk of fire due to damaged cables may be higher for ELV wiring than LV, because of the higher currents flowing.

 

[Taylortwocities]

I do not think that we are talking high current here.
He is planning to use

LV LED Tape with 60leds/metre.
.

Did you think it would need 35mm² armoured cable?