So I am planning a 3D printer build with a 1.5 meter cubed build volume! One issue I am running into in the planning phase is wire length. I was planning on having a ring terminal that the extruder fan, thermistor, heater, and extruder motor go into a ring terminal and run my own wires through the frame of the printer. Would this give me any issues with the thermistor? I have a feeling that the increased resistance may come back to haunt me. Has anyone tried this on their printer?

The wires will only shift the resistance a few ohms. Most (many? some?) thermistors used for 3D printers are at 100k at room temperature. A few ohms from the wire leads won't matter. Even if it affected the temperature reading, you can always compensate by setting the temperature higher or lower, whichever way corrects the error and gets you to the right temperature.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

As DD said or you could use a thicker wire gauge if you are worried. You might want to consider using thicker gauge wires for the stepper motors in any case. I believe that they are more likely to be affected by the resistance of long cables as they may draw in the order of a couple of amps.

As an alternative to thermistors and if you want more accurate temperature measurements, you could do what I'm doing and use 4 wire PT100s instead of thermistors. That may depend on the electronics you plan to use though. The Duet has daughter boards which support thermocouples and PT 100s. Thermocouples would not be an option as you can't really have joins in the cables other than the one cold junction at the tip.

Quote
deckingman
As DD said or you could use a thicker wire gauge if you are worried. You might want to consider using thicker gauge wires for the stepper motors in any case. I believe that they are more likely to be affected by the resistance of long cables as they may draw in the order of a couple of amps.

As an alternative to thermistors and if you want more accurate temperature measurements, you could do what I'm doing and use 4 wire PT100s instead of thermistors. That may depend on the electronics you plan to use though. The Duet has daughter boards which support thermocouples and PT 100s. Thermocouples would not be an option as you can't really have joins in the cables other than the one cold junction at the tip.

There are specially made connectors specifically for thermocouples, as well as wire to extend them with. McMaster in the US has them, I'm sure other places as well. McMaster 3869K35 is a male connector for K type, they have a variety to suit.