I install a mosfet on my 3D printer to help safely regulate the power from the power supply.

mosfet: http://www.ebay.com/itm/3DPrinterHe...

If that link doesn't work, just search up Ebay or Aliexpress.com. They are all over the place for anywhere between $8.00$15.00 depending on seller, shipping, etc.

Use a good size wire from the power supplies and bed. I would say 14 gauge minimum, 12 gauge even better.

The crimps I used are for 14 gauge and just barely fit the opening under the screw.

It continues to work fine as I demonstrated, but you can find more information here: https://3dprint.wiki/

I'm not an electrician. Do your research!