Could this be a wiring bug?

Once I couldn't reset my (whole house) RCD and by a process of elimination traced it to the central heating boiler that was in a brick lean-to outside. When I removed the cover off the JB that served as the "wiring centre" the problem was plain to see. A chain dead ants in an arc between live and earth.

That little lot did not seem to be upsetting anything RCD wise (not sure how conductive spider silk is?), although the lens on the front of the PIR had disintegrated, which meant it was doing strange stuff with the lights.

(all my outdoor circuits are on their own CU anyway so that problems like that don't get imported to the house side of things)

Silk was (and still is on a small scale) used for making insulators. It has a very high breakdown voltage.

Like paper insulation, its role tends to be for support (spacing) conductors, with something else (air or oil) also forming part of the insulator.

Ah! that's where my wing mirror spider has got to.

John

That would explain the lack of leakage problems then ;-)