I use heating cables to keep my home gutters from freezing. I have 3) cables; each connected to separate 15amp 110/120 VAC circuit breakers with separate illuminated switches. This lets me know when the power to each cable is turned on or not but doesn't let me know if the cable has failed or not. Two of the cables draw 0.83 - 0.75 Amps each at 120VAC. The third draws 3.35 Amps at 120VAC. Measurements were taken with a home grade Radio Shack digital multi-meter using a custom wiring plug in harness to put the heating cable in series with the multi-meter at the outside weather proof boxes. I don't want to have to go outside to check for failures in the winter with this method. Now to get to question.
? Do I need to use an aluminum enclosure for mounting the current transformers inside my home to get accurate switch on indications ?