What Size Electronics Cooling Fan? Mains switch wire gauge?

I'm in the middle of doing a major overhaul on my 12V cartesian machine. Adding TMC2130 drivers with an SKR 1.3 board, MeanWell LRS-350-12 PSU, power socket with switch, and TFT touch screen. I also plan on building an enclosure to reduce warping with PETG, so I've been designing a separate electronics housing to keep the electronics away from the heated enclosure.

Problem is, I've heard the TMC2130 drivers run hot, so I think I should add additional cooling. My first idea is to put in a 60mm Noctua fan at the back of the enclosure itself (enclosure size is 150mm W x 290mm D x 100mm H). I assume that would be powerful enough to keep the entire box cool, drivers included, but I honestly don't know how to calculate the right fan size for a given volume. My second idea is to install a 40mm fan inside the case, mounted to the controller in order to cool the drivers directly. The only problem I foresee with this is that it may be more effective to just cool the entire box (do the TMC2130s get so hot that they require direct cooling?). So, that's my predicament - cool the whole box or just cool the drivers? If I cool the whole box, what size fan should I use?

As for my other question, I'm also installing this 5A fused switch. I'm generally paranoid about using too small of a wire gauge, especially for mains power. I was planning on using 12ga wire, but it is so stiff and the 12ga spade terminals I have are too wide for the slots on my power supply. Is 12ga necessary for a 12V machine with a 200W heated bed? What gauge do you use for mains power?

200watt on 12v is 16.6666667amps (NB I very much doubt the SKR 1.3 can drive this directly, you probably need a external mosfet)

From this chart [assets.bluesea.com]

14awg should be fine

AWG # Diameter (mm) Diameter (inch)
12 2.0525 0.0808
14 1.6277 0.0641


Use silicone sleeved wires, with lots of strands, very flexible. Often used used in RC gear.

As for mains... depends on your countries mains voltage
Although it is higher voltage its lower current.
For here its 240vac. I just get a pc power cable from a local reputable store and cut off the plug im not using (but you always check phase, neutral and earth are the colours you expect)
Cable is marked as 1mm² (copper)

Edited 2 time(s). Last edit at 11/05/2019 02:07AM by Dust.

Quote
Dust
200watt on 12v is 16.6666667amps (NB I very much doubt the SKR 1.3 can drive this directly, you probably need a external mosfet)

From this chart [assets.bluesea.com]

14awg should be fine

AWG # Diameter (mm) Diameter (inch)
12 2.0525 0.0808
14 1.6277 0.0641


Use silicone sleeved wires, with lots of strands, very flexible. Often used used in RC gear.

As for mains... depends on your countries mains voltage
Although it is higher voltage its lower current.
For here its 240vac. I just get a pc power cable from a local reputable store and cut off the plug im not using (but you always check phase, neutral and earth are the colours you expect)
Cable is marked as 1mm² (copper)

Thanks, Dust! I am definitely using a mosfet, but I appreciate the advice on the mosfet wiring. I'm going to switch from the stiff 12ga I've been using between the PSU and mosfet to 14ga silicone sleeved wires with spade connectors. That should solve the overrun protection errors I've been getting with the 12ga wire not always having solid contact with the mosfet.

I'm in USA, so running at 120vac for mains. I've actually been wondering if it would be fine to do exactly what you suggested, just buy a decent power cord and use the wires from it for wiring the switch. It can't possibly require a thicker gauge than that of the cable delivering voltage from the wall, right?

For anyone with experience selecting case fans or cooling TMC2130 drivers, do you think a 60mm fan would be adequate for what I'm doing? Do you think an electronics fan is even necessary?