I am using it to power some 12v electronics with low amps. If they try to draw as much amps as possible, the wires heat. How do I prevent a PSU from putting out high amps whilist leaving the voltage at 12v? Same for 5v?

 

I don't think you can. Ohm's law says that a load will take the current it requires. Some power supplies will drop the voltage when this happens to prevent excess power from going to the load. I don't quite understand the meaning of "12v electronics with low amps". Does that mean the 12v electronics can run from low levels of current. If so why are you worried about it. If not you need to elaborate on what the loads are and why you are having a problem.

 

The solution is to use properly rated conductors, and don't overload the supply.

 

I am using it to power some 12v electronics with low amps. If they try to draw as much amps as possible, the wires heat. How do I prevent a PSU from putting out high amps whilist leaving the voltage at 12v? Same for 5v?

You are confused about how it works. Current doesn't push itself out of the PSU- it is drawn out by the LOAD. The load draws only as much as it wants. If you are overheating, then you're not correctly LOADing the circuit.

You should probably tell us what your LOAD is.

 

Remember Ohm's law also says I=V/R. So, at a fixed voltage, to get a low current the R increases.

 

Your wall socket can deliver perhaps 15A before the fuse blows, but you can plug a 1A load into the socket and it works fine, drawing only the current it needs.
Your power supply and it's load works the same way.