[Gaz64]

David,

I have a length of wire with a pin soldered to it, that I lightly pierce a wire in question, then tape the outside secure. The pin goes in near parallel to the conductor. The wire is now accessible for testing with a testlamp or multimeter. The wire only has a pin hole that is easily taped afterwards.

A testlamp can be a 3w bulb or LED, depending on what we are looking for.

Sometimes I also like to use a relay, as either a operated latch, or set to drop out if loss occurs, depends on what we are looking for.