It sounds doable, but since 240.5 B,2 references fixture wire, I believe you would have to use one of the wire types listed in 402.3 for it to apply.
If the tracks have end feeds, I’m not sure if those wires would qualify as "fixture wires", since those are more for branch circuit wire connection… although, 402.5 does allow fixture wires to be used as branch circuit wires as permitted elsewhere in the code.
Maybe run it by your local inspector to see what he thinks.
402.12 does reference 240.5 for overcurrent protection, so it looks like you can tap a 50A branch circuit with a #12 or larger fixture wire, but the actual allowable ampacity for the #12 fixture wire is limited to 23 Amps and likewise #10 fixture wire would have an allowable ampacity of 28 Amps, according to Table 402.5.
|