Safely assembling my project

Hi,

I am new to electronics, and am looking toward assembling my first project. I will be using a 220v to 24v converter, so part of my project will be high voltage.

I know I must earth my project case itself, and intend to use an IEC Appliance Inlet (or similar), but i don't know what else I need to consider, other than to try to cover all bare wires as much as possible. How do i go about physically separating high voltage components from low, do I need to?

This is for my personal use.

Any advice would be gratefully received.

Thanks
karl

Think pro-actively about preventing a risk of a fatal accident:

Imagine an insect like an ant gets into your project and starts crawling around on the mains circuitry - can
it ever form a link between mains and low-voltage sections? If so it will vaporize and create an arc
between the mains and the low voltage side destroying the low voltage circuitry and exposing people
to a shock hazzard.

So use separation and insulation to prevent this scenario - you automatically prevent prying fingers
from the same fate in the process. Be aware that mains can carry much higher voltages than the
nominal mains during a thunderstorm or when fluorescent striplights are switched (due to the big
balast inductor), so think several kV as the dangerous voltage you have to protect against.

If in doubt, don't risk it.

Apart from MarkTs answer and the recommendation that this should not be your "first project", consider a few things:

Thank you both for your helpful replies.
Karl

I would use a walwart or microusb supply if doing so was viable, instead of bringing mains voltage into my project box.

That way, assuming it’s a properly constructed supply, the device power is isolated and you just need to ensure that overcurrent event from malfunction or ingress of a foreign object can’t start a fire or something.

If you have mains voltage and DC on the same circuit board, do what the commercial designs do - you’ll notice how they have clear gap between the high and low voltage areas, and often they mill gaps in for good measure too. You can see this in any piece of old AV equipment (these are usually obtainium on trash nights or at the local dump).

ElCaron:
Apart from MarkTs answer and the recommendation that this should not be your "first project",

It's a good answer from a safety POV.

But when i started out it was the very first project as i could build little else without building a supply first.

It was all chassis and tag strips then though.

Many assume a pcb these days but using the 'old ways' should allow adequate safety.
Paying attention to cable anchoring etc.

I started out using valves with 2-300v HT supplies in my teens - and didn't get any bad shocks.

Mostly done on tagboards.

Just be careful and observe clearances etc

regards

Allan

Messing with mains power as an intro to electronics can lead to harsh lessons, from electrocution to fires to watching components go up in smoke. The last one is actually good in a way, as it helps one to learn, but for first projects can be disappointing.
I would suggest trying to either get an old power supply with the correct voltage you are looking for and proceed with the rest of the circuit, or even make a dc-ac converter and then continue on with the project if it is ac you are looking to learn with.
I have several old security system power supplies which are just a big walwart transformer taking 120VAC to 16VAC. I also have many old computer and printer supplies that give me from 12VDC-30VDC, and even one that has a split +/- supply.

If you are set on going with the mains, a few suggestions

-use a gfci power strip with on/off button. Use that button to power on/off the circuit without touching your project and make sure your project case is connected to the ground pin of the GFCI (not neutral)

-insulate the box from the board. Use plastic risers or even a plastic box.

-clearly mark on the board where mains power is and enclose that area with more protection.

-FUSES--use them

  • Don't rely on parts to just "sit still" while you are testing with wires. The parts WILL move, and normal reactions will be to try and grab it.

-Have a good understanding of the circuit you are making and don't just replace components or think ones unimportant without understanding the ramifications of such.

-enjoy

Thank you everyone,
Your replies have been very helpful.
Karl

tinman13kup:
-use a gfci power strip with on/off button. Use that button to power on/off the circuit without touching your project and make sure your project case is connected to the ground pin of the GFCI (not neutral)

This can possibly be dangerous. Not all countries have power plugs with defined phase, and from all the crap I have seen around, I assume not all power strips break both connections (they should, but I do not know if and where it is mandatory, and even if it was, I wouldn’t be too sure if all cheap strips are up to regulations). S in the worst case, your power strip could break neutral and leave you with live.