Properly insulating 240v terminals on power supplies?

kane

kane

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Just wondering if anyone has any tips on how they insulate the 240v terminals on their power supplies?

The first few I did, I just used a few pieces of gaffer tape to ensure it was all covered up. On the most recent ones I've hooked up, I've stuck a big blob of hot glue on each terminal, and then put a piece of plastic cut to size on top of it. Seems much better, but I'm wondering if there are any other solutions out there!
 
oldmanfathertime1000 said:
Kane some hot glues have chemicals in them that make it conductive to voltage. You might check on the package or google it.

(oldmanfathertime1000)
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Hmmm - I wouldn't have guessed that! The packet certainly didn't say anything along those lines, but what would be the most reliable way of checking this - check the resistance with a multimeter?
 
Checking with a multimeter checks that it won't conduct voltage at 1.5 to 3.0 volts depending on the meter. It is probably safe to assume that it isn't going to conduct at 240V but it's only an assumption of course. Checking conductivity at 240V or higher is the domain of megger (megga) meters. Covering with plastic or fibreglass to provide an actual mechanical spacing between the terminals and fingers is a safe bet.
 
AAH said:
Checking with a multimeter checks that it won't conduct voltage at 1.5 to 3.0 volts depending on the meter. It is probably safe to assume that it isn't going to conduct at 240V but it's only an assumption of course. Checking conductivity at 240V or higher is the domain of megger (megga) meters. Covering with plastic or fibreglass to provide an actual mechanical spacing between the terminals and fingers is a safe bet.
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Yeah, I've put a thick piece of plastic in there as a additional spacing, but I was more concerned about the fact that if the hot glue was actually conductive, it could create a short between the active & neutral wires (and/or earth), as I made sure that there was plenty of glue in there.
 
If your power supply is put inside an enclosure then there is no need to cover the terminals, because if we open up the enclosure to work on the equipement inside then we should really be isolating/disconnecting the power supply from the mains. Now thats the electrician in me talking.
But its always a good thing to cover your mains terminals if they are left exposed, even if its just adding a bit of electrical tape over the terminals just in case we forget to isolate the mains power before working within the enclosure.
 
ɟɐsʇǝppʎ said:
If your power supply is put inside an enclosure then there is no need to cover the terminals, because if we open up the enclosure to work on the equipement inside then we should really be isolating/disconnecting the power supply from the mains. Now thats the electrician in me talking.
But its always a good thing to cover your mains terminals if they are left exposed, even if its just adding a bit of electrical tape over the terminals just in case we forget to isolate the mains power before working within the enclosure.
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I don't have any of my power supplies in enclosures (I prefer not to run 240v into the yard) - I have them on a board in the garage. The reason I migrated from gaffer tape to the glue and piece of plastic is to ensure it's a little more solid - just in case my 2.5yo decides to stick a screwdriver in there. (even they're never turned on when he would be near them)
David_AVD said:
I think I'd be using a hard plastic piece over the terminals and not using glue as an insulator.
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Are you saying that you'd not put glue in there, as that could cause an issue? Or are you just saying to not rely on glue by itself as the insulator?
 
Kane said:
Are you saying that you'd not put glue in there, as that could cause an issue? Or are you just saying to not rely on glue by itself as the insulator?
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Yes, I would avoid using glue on the 240Vac terminals. How it will react with high voltage AC across it is unknown with some glue types.
 
Got to admit to using Nuetral Cure silicon on all mine these days, no obvious issues experienced, no tripped ELB's. Keeps fingers and screwdrivers away from accidental contact.

I would recommend to at least use a Silicon rated for electrical use, they are availlable

Phil
 
Phil,
That's old school. RTV is excellent stuff.
Personally i prefer holy carbonate / perspex shields.

Another issue with hot glue is it does cope with temperature swings too well. When cold it is brittle.
 
For custom covers we usually go for 3mm acryilc/perspex at work, or 1.8mm for more intricate covers. Not sure where it can be sourced from yet, but should be able to bend it into shape with a heat gun and over a bit of wood for a jig.


Otherwise Bunnings sells small sheets of polycarbonate, a bit more expensive but will also work.
 
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