Ian Jackson wrote:

I would be surprised if a lubricant was sufficiently viscous and had
enough 'body' to act as an insulating layer between two parts of
well-tightened a connector.

However, I have personal experience that Araldite can. This was used to
ensure that a reducing bush (PG11 thread to 5/8"), in the wall of the
housing of a CATV amplifier, remained securely in place. On all four
ports, there was absolutely no continuity between the outers of the
connectors and the housing.

Araldite seems to be a trade name for a variety of adhesives. There are
certainly materials other than the oil or light grease I was speaking of
which will interfere with continuity, and some of those adhesives are
apparently in that category. Kids, don't apply epoxy to your relay
contacts. Honey and contact cement might not be too good either.

Roy Lewallen, W7EL