The telco's test gear applies up to +/- 275 volts to probe the "signature" of various self-test devices in the loop plant
Well, I do know that OUR secondary protectors clamp at 235 volts and have sneak current fuses. So if they were applying that kind of voltage both they and we would know about it.
I also think that that kind of voltage would pose a real danger to any tech since they would not expect anything higher than ring voltage or maybe an open carrier circuit voltage. So I kind of doubt this test method would be used except under strictly supervised conditions if you are correct.
-Hal
