Specific wire type for hot end and heated bed

There was a forum post somewhere where nophead says that the highest fire risk on the Mendel i3 is the wiring that attaches to the hot end and the heated bed. Basically after so many hours of use, the stranded wire frays and sparks/catches fire.

What is a good wire to use? How often should this wire be replaced? Would mil spec teflon coated wire help? (ie, this stuff? [www.apexjr.com] )

Thanks!

I would think there is no specific wire type that makes these problems go away, I would rather deal with it by careful wiring. Make sure that any bends to those wires do not stress a small length of wire. If the stress is distributed over a longer length of wire, the life span of the wire is greatly increased. That said, I would assume finer stranded wire would be less prone to fraying than coarsely stranded wire. This is just my 2 cents though, my machine doesn't have that many print hours on it yet.

/Andreas

for my heatbed, i used normal appliance line... and for the extruder, a thicker line with telfon covering. (which came with the extruder)

In my main printer i use cable specified for cable chains for all moving parts, especially the high voltage printbed.

---

[www.bonkers.de]
[merlin-hotend.de]
[www.hackerspace-ffm.de]

I think the minimum bend radius depends on the thickness of the cable and needs to be quite large for normal cable.

I use ribbon cable as the strands are very thin and flexible and use enough in parallel to handle the current. I then use polypropylene strips to act like a miniature cable chain. See [hydraraptor.blogspot.co.uk]

---

[www.hydraraptor.blogspot.com]

Flex along the length of the cable isn't so much of an issue as at the joints - where the cable is soldered to the heated bed or enters the heater on the hotend. At these points you need strain relief - somewhere to anchor the cables to so that there is short length between the joint and the anchor point that does not move.

This is one advantage of Bowdens: the tube can be used to enforce the minimum bend radius, and the extruder can be used as a wiring hub between electronics and the E-stepper and effector. Nylon braided tube and PP spiral wrap work well, though Velcro cable ties spaced evenly made for easy wiring changes on my Tantillus and kept the entire Bowden length visible.

These things are awesome: [d2t1xqejof9utc.cloudfront.net]
I always go overspec on the wiring. I use 15A wire on my 5A bed.