I'm building a new 3D printer (P3 steel type, 24 V setup) and I've been struggling with the wire gauge to connect the PSU (24 V, 15 A) to the SKR 1.4.

From my calculations, 1.5 mm2 should be fine, but I'm thinking about using 2.5 mm2 just to be safe. What are your opinions on this?

  • 1
    $\begingroup$ As always: It depends. Are you planning to connect your heated bed directly to the board? Or are you using an external MOSFET for it that'll connect to the PSU? Also, what are the specs of your bed? $\endgroup$ – towe Nov 4 '20 at 7:06
  • $\begingroup$ I'm planning on connecting directly to the board, unless a Mosfet is absolutely necessary. The bed is 24V and 3.6ohm (read from my multimeter, manufacturer claims 3.2ohm). $\endgroup$ – Nuno R. Peres Nov 4 '20 at 11:05
  • $\begingroup$ 3.2 Ohms results in around 8 A. Together with the around 2-3 amps for the heater, drivers and fans, 1.5 mm² will be fine. Larger obviously doens't hurt though. I went with 10 AWG (6 mm²) for my heated bed, even though that only draws around 20 A - though I used silicone insulated wire for the flexibility. $\endgroup$ – towe Nov 4 '20 at 12:13

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