I recently bought a Hictop Prusa I3 (from Amazon, shipped from China). I thought it looked a great printer for a beginner and would allow me to learn a lot about 3D printing while I assembled the kit.
The good news is that I have assembled the printer successfully and have been able to print some very high quality prints. However I have a worry with the power source after reading a number of reviews of the product.
The review below is taken directly from amazon:
Electrically this is very dangerous, especially at our 240V rather than the 110V the Americans use. The power supply comes with simple terminals to connect the mains lead to. This is much like wiring a plug - strip the wires and connect them to the terminals. Except on this printer there’s no strain relief for the cable (so the only thing stopping the live wires pulling out is the terminals themselves), despite the power supply being in a metal case and having an earth terminal there’s only a two wire lead supplied (ie no earth), the terminals aren’t fully enclosed and the conductors look vastly under the 0.75mm2 stated. Any one of those would make this extremely dangerous and illegal to sell in the UK. I suspect the only reason they can get away with it is that it’s sold as a kit. If you buy one of these kits you MUST use a replacement lead with the correct size wires and connect up the earth terminal. You MUST also provide a strain relief to the cable and enclose the power supply terminals. That’s the bare minimum. If not there’s a very serious risk of the whole metal frame getting live. An RCD is also a sensible precaution.
I am a mechanical engineer by trade and have very little experience in electronics. Has anyone purchased this printer and made any modifications to the power supply, if so any assistance would be hugely appreciated.
Thanks
1 Like
Xeno
2
The strain relief for the cable is just regulation, and not something that could cause problems or fire when left alone,
the strain relief prevents problems if the able is janked hard, and make sure the connectors wont come loose and cause a short.
Just make sure you place the printer and wires in such a way you wont snag on them, there wont be any problem.
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Thanks for your reply, my printer is in the corner of a room with all wires out of the way so no worries here.
What about this section of the review?
‘despite the power supply being in a metal case and having an earth terminal there’s only a two wire lead supplied (ie no earth), the terminals aren’t fully enclosed and the conductors look vastly under the 0.75mm2 stated. Any one of those would make this extremely dangerous and illegal to sell in the UK. I suspect the only reason they can get away with it is that it’s sold as a kit. If you buy one of these kits you MUST use a replacement lead with the correct size wires and connect up the earth terminal.’
Do you recommend changing the lead, and if so what would you suggest?
Thanks again
cobnut
4
Hi @bayns001 personally I’d replace the lead, including an earth. If you’re not happy doing it yourself, get a professional to do it. It’s really not ever worth cutting corners with mains electricity…
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Thanks for your comment. I agree and think its probably best to get a safer lead. Do you have a recommendation on where I can get a suitable one? Any where I can order online?
I should be okay to do it on my own, wired the rest of the printer fine and it hasn’t broken yet. I just want to be sure I am buying the most suitable and safe cable.
cobnut
6
You can get mains cable in pretty much any DIY store or Maplins. I’d recommend going to a local hardware shop (if you’re lucky enough to still have one). What you want is “appliance flex”, but it should be obvious. Make sure the cable is suited to the power draw of the unit.
I might be tempted to go for a heat-resistant cable as used for irons and the like (you can recognise it 'cos it’s the one with a braided cotton outer, usually white/black mix). Although in theory your cable should never get anywhere near the hot end, it’s a nice extra precaution.
Again, I have to say that if in doubt, seek professional advice…
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any link to the kit so we can see what PSU it is?
I got one of these meanwell PSU’s and i have connected it with a mains cable from an old pc where i just cut off the plug that goes to the pc. i fitted each wire in the cable with an automotive ring terminal just big enough for the terminal screw to go through.
or you can use the fork type terminal also for automotive use. if it does not fit the terminal you can fold it so it becomes one pin instead.
and with a bit of luck you can use a zip tie to secure it to the PSU
btw… the one that made that review is not quite right. “this is very dangerous, especially at our 240V rather than the 110V the Americans use.”
its not the volts that is dangerous, its the Amps that kills
Dont be scared if you hear the words mains voltage, but a dose of common sense will be a good tool to have at hand
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oh i forgot… 0.75mm square is good for 10A on the input side.
you can roughly calculate what the input A is if you know the output A
say its 30A out then it will be
230/24 = 9,58
30/9,58 = 3,1 A
give or take a little for loss in the PSU.
But yes i would not go under the 0.75mm square anyway.
Hi, thanks for your response.
The link you sent is the exact one I have. I have attached an image of the current set up of it. I am going to go to a hardware store this afternoon (as advised below) and buy one of the heat resistant mains cables.
If there is anything else you can think of that I may need it would be much appreciated.
Could you possibly send me an image of your setup so I can see what I’m aiming for?
Thanks again
Thanks for your response
I am going to take a look this afternoon at my local hardware store to see what I can find.
Please see the images attached above to see my current setup
