conduit support.... working to find the proper clearance for the conduit supports. I have a nice snug fit on these. the measured conduit OD is pretty close to the listed but not exactly. these conduits are from Heyco (same suppler for the snap bushings) and are flame retardant UL94-0. they are certified to extinguish any burning within 10 seconds. I'll test for that.
I had some Van's conduit but threw it away because I was busy building a loft and really cramped for space. I'm not sure of the Van's conduit rating. I believe the Heyco conduit is stiffer than the Van's, if I remember correctly.
I don't know why there would be a need for anything larger than 21mm nominal diameter.
these are 13, 16, 21, and 28 nominal diameter.
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my measurements
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Heyco sizing and UL rating definition
UL-94 is the Standard for Tests for Flammability of Plastic Materials for Parts in Devices and Appliances. Within this standard, materials are subjected to various burning tests to see their performance in flammable conditions. Flammability UL 94 V method “evaluates both the burning and afterglow times after repeated flame application and dripping of the burning test specimen” in a vertical burning test.
To attain the UL 94V-0 standard, samples must have met the following criteria:
Burning combustion is not sustained for more than 10 seconds after applying controlled flame.
Total flaming combustion time for 5 samples does not exceed 50 seconds.
None of the samples burned up to the mounting clamp by either flaming or glowing combustion.
None of the samples dripped flaming particles that result in the ignition of the surgical cotton below them.
Samples did not exhibit glowing combustion for more than 30 seconds after removing the second controlled flame.
