Looked at a 46 year ols 200 amp Pushmatic today AC sensor showed the panel cover to be live then dead then live again awhile later. I didnt remove the cover
Are You talking about a tic tracer or did You put a wiggy on it?
Most likely false reading unless the house was built with a completely ungrounded system. Tik tracers canbe unreliable as some are oversensitive.
I wouldn’t say they’re “unreliable,” because they are designed to alert you that voltage is in the proximity. It was doing its job correctly.
You were using the wrong tool. The NCVD will alert when you place it on a breaker. This does not mean the breaker will shock you if you touch it. It simply means there are live components in the vicinity.
To check for actual voltage on any given part, you should be using a volt meter or a “wiggy.”
The cover should not have been live if it was properly bonded. If bonded it should have tripped the breaker if a live wire was in contact with the enclosure or cover.
Drop 'em once and they’ll never work the same. Users hold it against the object and unknowingly move it slightly which sets off the alert and they mistake it for voltage present. Hols them a few feet under a fluorescent troffer or a LED fixture, they signal voltage is present. Don’t completely rely on these. Best tester is a multimeter, whether digital or solenoid.
AC current gives off a magnetic field. These NCVD are good at detecting this field and alert the user to potential voltage present. Not all are created equal is assured but their are a few good models out there. The orange models from Santronics (I think that’s the name… I used to sell them) are the best in my opinion.
Just remember…they are but a tool and never rely 100% on tools without confirming with a redundant tool. (Eg. Another NCVD is a good start). In terms of Wiggy’s…be careful as going into the panel does breach your SOP. However, everyone knows their own limitations so to each his/her own.