Housing control circuit ok?!

Hi there!

Im building a small control circuit for the housing of my laser cnc.

Can you see any flaws in this circuit?

Since I want to power the cnc control circuit with this setup too, I dont want to make any mistake and blow up my laser cnc control board with this.

The power supply delivers enough amps (6.67A) . Im using wires at 0.14mm2 not longer than 60cm. They are rated for 80W so I hope they are enough.

Thanks in advance!

Can we assume you are using insulated wires? The type of insulation that is rated for the voltage you are using is equally important.


Thanks Paul for your reply!

Can we assume you are using insulated wires?

Im using these type of wires:

Did you also had a look at the circuit?

It appears you are on the correct track, the drawing is great. Here is a tool that will help a you a lot: http://www.ohmslawcalculator.com/ohms-law-calculator It is an online calculator. You can use this to check your wire sizing. I cannot check that because I do not know how much the motors pull but you can using the calculator. Another link: Voltage Drop Calculator will allow you to calculate the voltage drop via your wiring.

This is what your link shows:
Insulated copper
strand 1-wire, 1x0,14mm²
multistranded (18x0,1mm)
material flexible
colour Gray
about 1.1 mm
cable length10 m
Electrical values
electricity 0.8 A
tension 100V

This is the max current 800mA * 12V = 9.6 Watts as the capacity of the wire at 12V. The power supply is as you state is 80 Watts. You need to check worse case current in each leg of the circuit. A trick to extend the switch life is put a ,1 cap across each switch with an inductive load such as the motors and the main.

Good Luck & Have Fun!



For these parts of the circuit 0.14mm2 it should be fine: the first fan draws 200mA, the LEDs draw about 650mA and the last 2 fans draw approx. 400mA (200mA each).

It seems that the wire would be too thin for the power switch, power jacket and power to external cnc board right? It should be more like 0.6-0.8mm2 according to the reference page you provided for these connections?

I'd definitely consider add fusing - perhaps polyfuses? Otherwise a short circuit might lead to the thin wiring burning.

Thanks all for your replies!

I'd definitely consider add fusing

I will buy a fuse; good point!

For the low amp parts of the circuit (LEDs, Fans) the wire 0.14mm2 is sufficient right?

I only need thicker wires (0.6-0.8 ) where actually a max of 80W goes through (Powerjacket, Powerswitch, CNC board output)?