Wayne,

It seems that the 'shielded' wires are assumed to be multiconductor (twisted pair, etc.) and 'insulated' are single wires.

As for the wire construction, I'm not surprised that the spec doesn't get into a high level of detail. I expect the requirements are good for most configurations, and you'll find that with some hardware you can safely take exception to the requirement with agreement from your customer.

Ben

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Wayne Thayer - EXT
Sent: Wednesday, August 17, 2016 1:22 PM
To: [log in to unmask]
Subject: EXTERNAL: [TN] Harness bend radii

Hi All-

Finally back "in the saddle" after a tumultuous year. First, I got a fantastic job opportunity to move to the heart of the PNW. Worked my butt off for 7 months, then was let go. Then another sprint to see if I could find ANYTHING in the immediate area, which took another 2 months.

Anyway, here I am at Insitu, maker of premium recon/intelligence UAVs.

So here's the question:

IPC/WHMA-A-620B Table 14-1 lists different bend radii for "unshielded" vs "insulated (non-polyimide)" wires, but there is nothing in the "definitions" section to give me a clue as to how to tell the difference. Anybody know how we're supposed to interpret that? For the "S" version of the document, they pulled out the "insulated" line.

And here's a follow-up question:

Why isn't there anything on wire construction in the spec? The build-up of the wire makes a huge difference to whether a certain bend radius can damage a wire. For example, I'm looking at #12AWG, and I've found (#conductors/gauge each conductor) ranging from 19/25 to 665/40.

Thanks!


Wayne Thayer
Insitu Contract Engineer
Desk: xx-xxx-xxxx
Cell: 443-534-8036
E-mail:  [log in to unmask]<mailto:[log in to unmask]>