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I'm repurposing a PSU that I recently replaced. I'm using it in a project that needs high current supplied. I don't need all the wires (as you could imagine), but I don't know how to seal them off safely.

I was thinking about trimming them shorter and then adding a bit of electrical tape over the end and doing a little bit of shrink wrap to hold that in place. Is this a good idea? I generally like to stay away from electrical tape, but I can't see any alternatives, and the shrink tubing would hold it in place. Ideally, I would desolder the wires from the PSU, but I'd rather not mess around with it and all the warnings about capacitors. How should I do this?

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up vote 10 down vote accepted

I would cut the wires to a convenient length, and then use shrink tube over the ends. If you cut 1" of shrink tube, and cover 1/2" of the wire (leaving 1/2" of empty tube), it would offer a lot of protection.The empty section of the tube would neck down nicely...

RJR had a good idea: if you bend over the last cm of wire before heatshrinking the end, and put the heatshrink over the doubled-up wire, then the swelling at the end will keep the heatshrink tubing from slipping.

Is this PSU from a desktop computer? If so, no need to worry about shocking somebody with the output. All the voltages are too low. Do be safe with the incoming AC wires, through!

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Yeah, the PSU is from a desktop computer. Still, the capacitors are dangerous. I'm more worried about shorts than electrocution, although it does have short circuit protection built in. – Anonymous Penguin Apr 29 '14 at 23:20
@AnnonomusPerson Any high voltage stored in the caps shouldn't make it's way to the output wires, or computer components would be getting fried. Of course, it's always better to be too safe than not safe enough :) – bitsmack Apr 29 '14 at 23:24
I concur: Put an inch of tight-fitting heat shrink on the wires, and torch it. Should be nice and tight, and a good seal. – Jon Watte Apr 29 '14 at 23:24
@bitsmack I know it won't reach output. I was merely referring to desoldering the wires... although those are still safe I don't want to touch something inside it... yes it is good to be safe :) – Anonymous Penguin Apr 29 '14 at 23:53
I'd suggest bending over the last 1cm of the wire before adding the shrink tube. This creates a 'ridge' that will prevent the tube from slipping off. – RJR Apr 30 '14 at 1:14

I've found that using some wire nuts with some electrical tape is your best bet. Here's a full tutorial.


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A good way to seal open wires is also hot glue. You could also use a shrink tube and put some hot glue into the open end.

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