EEVblog Electronics Community Forum
Electronics => Beginners => Topic started by: Skippy on February 16, 2015, 01:35:40 pm
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Stupid question time:
I've got some LED lights and I want to power them with something like this:
(http://www.recyclepowers.com/pimage/12V10A120W__.jpg)
My question is how do I use this without there being exposed live cables where you plug the power cable in? I guess you screw down on stripped cable on the Live, Neutral and Earth lead, but how do you stop people getting their fingers in- I see it's got a piece of plastic over the top but is this really enough? I don't want to put it all in a box, as I quite like the heat being able to get out.
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That isn't designed for use in publicly accessible locations. It needs to be installed in a place where fingers can't reach it.
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Indeed these are made for inside cabinets, you need cooling holes or a fan in the box or cabinet, and with the fan you need protection from again fingers :D
You could put a smaller metal/plastick box just around the contacts such that it would be mechanically mounted to the metal and impossible for people to access the contacts. Since the metal enclosure is earthed there would be no risk there.
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Yes, the power supply needs to be mounted in a suitable enclosure so no one can touch it.
Where did you buy it from? It looks dodgy. There's a double insulated symbol on it, then there's an earth terminal which is contradictory. Double insulated equipment doesn't need an earth connection and normally has a plastic enclosure and if it does have a metal box, there's a piece of plastic between it and the live parts.
It certainly needs to be earthed and I'd be tempted to earth the secondary too as it might not be designed with sufficient insulation.
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Cheers everyone. I haven't bought one, I was just thinking about it. I've already got a 12v 10A one that looks like a laptop power supply, but it gets very hot in use and I didn't feel confident using in a lighting application where I might be leaving it unattended for a long time.
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Is it cheap? How does the price compare to a reputable distributor such as RS components or Digikey? If it's 2/3 of the price that's fine but it it's under half then be suspicious.
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If that's a no name China brand run away very fast, unless you want to replace it every 12 months and have massive EMF emission issues. Try Meanwell if you are on a budget and put it all in a fan cooled enclosure.
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Or TDK-Lambda,
12V 150W €36 Conrad 511831 - 89
12V 100W €25 511827 - 89
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An average computer PSU can provide more than 10A at 12V. They're much easier to obtain and use normal 'computer' or 'jugplug' C13/14 connectors.