Just as an aside - SPDs. My guess is that a significant number of these devices have been installed during the last couple of years. How many I wonder, have had to be replaced because they have been activated one time too many?
But they don't really "run out" like that. In theory they can handle transients indefinitely: they only need replacing if they encounter a too-large transient which breaks the internal fusible link (and flips the indicator window and/or switch).
Just as an aside - SPDs. My guess is that a significant number of these devices have been installed during the last couple of years. How many I wonder, have had to be replaced because they have been activated one time too many?
But they don't really "run out" like that. In theory they can handle transients indefinitely: they only need replacing if they encounter a too-large transient which breaks the internal fusible link (and flips the indicator window and/or switch).
