How many PSU terminals to use

wilriker

I read https://duet3d.dozuki.com/Wiki/Power_Wiring and https://duet3d.dozuki.com/Wiki/Wiring_and_hardware_differences_from_RAMPS_etc where in the latter it says

If your RAMPS system had a single PSU, you can feed both PSU cables into the single VIN terminal block on the Duet[...]

It also says alternatively one could run a single heavy duty cable.

My PSU has 240W and 3x V+ and 3x COM terminals. Somewhere deep back in my mind I remember I once heard/read that the power will be spread among those terminals about equally. That would mean I would have to run three cables from the PSU to the VIN terminals on the Duet. Now this conflicts with what is stated on the above page.

My question now: will one (sufficiently thick) cable be sufficient or should I rather run three cables to cover all terminals of the PSU? Currently I am using two cables but I will have to do some rewiring in the near future and I want to do it "right" then.

dc42

How much current does your bed heater draw?

wilriker

Somewhere around 12 amps. It's a cheap Anet heated bed where specifications are unclear and I have no equipment to measure it exactly but it should be somewhere between 10 and 15.

dc42

I forgot to ask, are you using 12V or 24V power?

If it's 12V then your PSU is rated at 20A. With a 12A bed heater, two cables should be sufficient.

wilriker

@dc42 Yes it is 12V and I use one set of 2.5mm² cables (I added) and another set of 0.75-1.5mm² cables that were included with the original printer (have never measured their exact diameter).

OK, then I will probably keep the wiring for this part and just have to worry about cable routing. Thanks!