I apologize in advance if this is off-topic, but I really need to understand what's going on...
While doing some renovations, it was found necessary to relocate a few runs on BX (aluminum-sheathed) cable. One of the cables ran between a single-pole thermostat and a 240V baseboard heater. After trying unsuccessfully to locate the breaker, I turned up the thermostat to ensure both hot lines were energized and cut through it (while wearing arc-flash protection, or course), with an old set of linesman's pliers.
Guess what? The breaker didn't trip! I stripped off a few inches of aluminum sheathing and bared the ends of both hot conductors. When I touch them to the ground conductor, there is only a very small spark and the breaker DOESN"T TRIP, even after holding it for several seconds.
I confirmed that there is 118 VAC in reference to ground on both hot conductors. Interestingly, there is ZERO potential between the hots, which leads be to think the circuit was improperly connected from the time it wa installed and that the baseboard heater never worked. Regardless of this oversight by the installer, this should not cause a breaker to fail to open.
Definitely a top-ten entry in my weirdest encounter.
Any suggestions, guys?
While doing some renovations, it was found necessary to relocate a few runs on BX (aluminum-sheathed) cable. One of the cables ran between a single-pole thermostat and a 240V baseboard heater. After trying unsuccessfully to locate the breaker, I turned up the thermostat to ensure both hot lines were energized and cut through it (while wearing arc-flash protection, or course), with an old set of linesman's pliers.
Guess what? The breaker didn't trip! I stripped off a few inches of aluminum sheathing and bared the ends of both hot conductors. When I touch them to the ground conductor, there is only a very small spark and the breaker DOESN"T TRIP, even after holding it for several seconds.
I confirmed that there is 118 VAC in reference to ground on both hot conductors. Interestingly, there is ZERO potential between the hots, which leads be to think the circuit was improperly connected from the time it wa installed and that the baseboard heater never worked. Regardless of this oversight by the installer, this should not cause a breaker to fail to open.
Definitely a top-ten entry in my weirdest encounter.
Any suggestions, guys?