Flat 12AWG Wire Legal?

[Al Skierkiewicz]

Bryce,
I would check the BOM costing descriptions again. Think of buying a 4x8 sheet of plywood but only using 2x2 on your robot.

[EricH]

Originally Posted by Al Skierkiewicz

Bryce,
I would check the BOM costing descriptions again. Think of buying a 4x8 sheet of plywood but only using 2x2 on your robot.

Al, if 4x8 is the smallest available size of that plywood, the entire 4x8 sheet has be accounted for in the cost accounting. That's how I read [R16]'s blue box, last example.

[Al Skierkiewicz]

R16
Example: A team purchases a 4 by 4 ft sheet of aluminum, but only uses a piece 10 by
10 in. on their Robot. The team identifies a source that sells aluminum sheet in 1 by 1 ft
pieces. The team may cost their part on the basis of a 1 by 1 ft piece, even though they
cut the piece from a larger bulk purchase. They do not have to account for the entire 4
by 4 ft bulk purchase item.

There are local A/V and home theater shops that do sell these materials by the foot. Some research is necessary.

[Bryscus]

Originally Posted by Al Skierkiewicz

R16
Example: A team purchases a 4 by 4 ft sheet of aluminum, but only uses a piece 10 by
10 in. on their Robot. The team identifies a source that sells aluminum sheet in 1 by 1 ft
pieces. The team may cost their part on the basis of a 1 by 1 ft piece, even though they
cut the piece from a larger bulk purchase. They do not have to account for the entire 4
by 4 ft bulk purchase item.

There are local A/V and home theater shops that do sell these materials by the foot. Some research is necessary.

In that case you'd be fine. But if you can't find a supplier for purchasing by the foot (for the exact part) you can't do this.

- Bryce

[JamesBrown]

Originally Posted by Al Skierkiewicz

Sorry I didn't see this post earlier. There is nothing illegal with this wire being used on the robot. While it is not color coded and can be used on the output of controllers, there must be some marking on it indicating polarity. I am often cautious of using "audio" wire as many companies over state specifications. What may be termed #12 may in fact merely act similar to #12 in this application. Robot wire specifications are taken from the NEC handbook for open (not in conduit or confined spaces) wiring. Another thing I would consider when looking at this wire is it's survivability on a moving robot. Bends over structural metals could breakthrough the outer cover exposing the conductive material inside.

http://www.pacificcable.com/Picture_...me=PCC-12-2-50 This site has a simmilar #12 wire listed as only being rated to 20A, FIRST, and NEC rate 12 gauge wire at 40 amps (41 for NEC). I would want a better understanding about where this 20A rating comes from before using it on a robot. The Flatwire brand site seems to imply that its product doesn't comply with NEC standards as they mention a new line that does comply to be used for power distribution.

[Al Skierkiewicz]

James,
Wire specs for NEC are determined by temperature rise for the insulation and by voltage drop at specified current over a specified length. In the case of the flat wire, certain signals have a hard time propagating down flat wire. For audio (and other AC currents), the shunt capacitance also becomes a factor as the max 80' length spec alludes. The 20 amp spec is likely because this product is intended to be painted over. At more than 20 amps continuous, the paint would likely start to bubble.
As for NEC current specs, the test on a single wire size is how much current can the wire transmit before the voltage drop at the end of a standard length exceeds a certain percentage. The current/voltage standards used for aircraft instruments is also used and more stringent.