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Cable Size (DC Long run)

shockuk

Jul 25, 2010
4
Joined
Jul 25, 2010
Messages
4
Hi all,

Wondering if you could help me size up cable for a stair lighting project.

I would like to create a "string" of led lights, however this project differs from a conventional LED lighting project.

Lots of stair lighting projects are designed without the ability to change LEDs.

The "bulbs" / diodes need to be replaceable in the future, so I was thinking of using LED W5W (car sidelights), they're single LEDs and rated at 12v 0.02a (basically a LED and resistor in a convenient form factor). (Example: http://www.ebay.co.uk/itm/2x-Car-LED-501-T10-W5W-WHITE-XENON-Side-Light-Bulbs-UK-/380628989761 )

W5W sockets and W5W LEDs can be purchased very cheaply online, especially when direct from manufacturer.

There is approx 5 metres between the transformer and the first LED (the whole string would be approx 10metres total). There would be 13 LEDs in total, approx 0.26 amps, 3.12 watts.

I would hope that I could use 1.5mm twin cable for this project. Please see picture for details :)

Would 1.5mm cable be adequate, or will the voltage drop be too high for such a long run?

Let me know what you think, and i'm curious if people think using W5W lights is a good idea or if you think it's a bad idea. ;)

Thanks very much,
Shockuk.
 

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duke37

Jan 9, 2011
5,364
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Jan 9, 2011
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My data book is old with a mixture of imperial and metric units but I think that 20m at 0.26A would drop 0.05V which is neither here or there.
 
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