I am at the point of wiring my first build and I was wondering what the sizing of the wires should be and in particular the wires leading to the heated bed and the hot end. Also I am considering a removable extruder and wanted to know what anyone is doing about disconnecting the wiring from the extruder to change it out with another. I have seen some folks using a db-15 connector but I wanted to hear what others had to say about the matter. Thanks.

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The wires should be flexible and capable of handling the amperage (2A for a 20W resistor hotend, more for a cartridge, 10A for a 120W heatbed).

Nophead uses multiple conductors of ribbon cable for the Mendel90 -- See [reprap.org] for good examples of sizing ribbon cable (12x26AWG wires each way) and plain stranded wire (18AWG) for the heatbed.

The Mendel90 also uses the DB9 to enable quck change of the extruder.

Edited 1 time(s). Last edit at 04/10/2014 11:43AM by DaveX.

The wire gauge for anything carrying signals - e.q. end stops - is not extremely important. You can go small - 24 gauge or 26. As a general rule. though, if something is generating heat - such as the heated bed or the hot end(s) - then you need beefier wiring.

For the heated bed - which draws up to 10 or 11 Amps, I wouldn't use anything less than 20 gauge - 18 if you have it. I think the vast majority of people who have difficulty heating their print beds probably have undersized wiring (or a bad solder joint). If your wires are undersized, they will heat up - so you can check them and up-size if you think it's needed.

The hot end is a little less demanding. I think something in the 22 to 24 gauge is fine. This gauge is probably also fine for the steppers.

As far as the DB connectors is concerned, it's generally fine, BUT if you are going to use this connector/cable for the heating element on a hot end then I'd use two or perhaps 3 of the conductors to effectively increase the gauge. I do not recommend you use this kind of cable or connector for the heated bed