Safe to Cryo Assembled Power Cable?

I can't imagine your cables having a torque value that would be an issues here (if at all). I'm thinking this requirement is for fitted machined components that are actually torqued to spec or fit. As cooling will contract the items and increase the potential torque values or potentially having two type of materials that contract at differently rates and could damage critically torqued assemblies.

 cables are just not a critically torqued assembly. Loosen the connector sleeves if your worried about it as that's the only fitted area I think could be a concern (probably not as most are hand tight at best).

I can not say what the cyro process with do to the insolation on the cables though that's a question I would have. think cracking and shrinking issues.

I'm just going on the experience I've had in the mechanical fields (I'm an Electro-Mechanical, Hydraulic-pneumatic technologist in the Canadian Navy, specializing in Submarine service).