What are the basic guidelines for safely using a "bare" unenclosed power supply (random example)?

As a relative novice, my thoughts are:

  1. Definitely need a separate enclosure
  2. To avoid overheating, dont put it in a separate enclosure
  3. Well, use a separate enclosure, but drill holes in it or something to allow ventilation
  4. If it'll be used where there is water nearby (like a kitchen), definitely don't drill holes in the enclosure to lower the risk of splash damage
  5. Maybe mount it somewhere hidden where it has plenty of air and no risk of water
  6. Well now you have bare 120v AC connections, and someone will get shocked
  7. Go to #1

For my project (overly complicated under cabinet lighting) I've decided that using multiple fully sealed power bricks will be the way to go. But I'm curious what the correct way to handle "bare" power supplies is.

  • \$\begingroup\$ And the answer is - of course - it varies, depending on the situation. But in no case leave 120VAC (or 240 VAC) connections bare and exposed. I think that also makes this likely to be closed as too broad, opinion-based, and generally not a good question for this format, but I'll leave that up to others with a better sense of that in this community. \$\endgroup\$ – Ecnerwal Feb 7 '16 at 23:35
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    \$\begingroup\$ I have to criticize your random example a bit. (1) It doesn't come with a datasheet. (2) It's not unenclosed. This is unenclosed (open frame). \$\endgroup\$ – Nick Alexeev Feb 8 '16 at 0:03
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    \$\begingroup\$ I don't see any UL or other safety agency markings on your example. My thoughts are it would be safest to deliver it the nearest center for recycling electronic waste. \$\endgroup\$ – Spehro Pefhany Feb 8 '16 at 0:27
  • \$\begingroup\$ Rule number one: Horse Sense \$\endgroup\$ – Charles Cowie Feb 8 '16 at 1:19
  • \$\begingroup\$ My random example was the first hit I found when looking for 5V 40A power supplies. Based on the reviews I figured it was trash, but it got the point across I hope. :) Whats the term for these type of power supplies, versus whatever the right term for a "brick" is? \$\endgroup\$ – Joe Feb 8 '16 at 4:52

You've got most of the right thoughts there in your lists. Open power supplies like that provide no prevention for water or dust intrusion. The big advantage they have however is far better air flow for superior cooling compared to the encapsulated brick type modules.

They're generally not used outside enclosures as stand alone units. They're generally integrated into products to save the manufacturer from having to design their own power supply.

They just need to be placed such that any unwanted contaminants won't get in. This includes random bits of wire or other loose material that could go around the shop.

As an aside, for (what I assume is) LED lighting there are very efficient fully sealed AC to DC modules which wouldn't require direct air cooling, and could be sufficiently cooled by being secured to a heat sink. Some examples include these Buck Puck products from LuxDrive. I've used them, and they work pretty well.

Buck puck BulletBuck

There's lots of other products on the market too.

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  • \$\begingroup\$ Thanks! Yeah, my project is LED lighting, but the "overly complicated" bit is that I'm using strips of WS2812B LEDs. My understand is that each has an embedded LED driver, I just need to give them a good source of 5v. Looking at a max draw of 18A right now, possibly more \$\endgroup\$ – Joe Feb 8 '16 at 4:50
  • \$\begingroup\$ I see. In that case a simpler fixed power supply is what you need. Those are pretty easy to shop for on places like digikey. Just pay attention to the efficiency to see how much heat they'll generate and be sure to leave some overhead so you're not running the system right on the limit. \$\endgroup\$ – alphasierra Feb 10 '16 at 23:52

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