Archive of the former Yahoo!Groups mailing list: MOTM

MOV's in parallel are not able to equally share the load of a high current impulse. The weakest
varistor will take the majority of the surge and this will lead to premature failure. As
individual varistors fail, the level of protection declines.

Parallel MOV devices have limited energy dissipation capabilities. As a result they age if
subjected to a high-energy impulse. This aging decreases product lifespan.

As parallel MOV devices age they begin to leak current. As this aging process continues more
current flows adding to the problem. If the devices' fuses/breaker does not operate (which takes
the protector off line) the device may catch fire.

If you "want to see the math", get a copy of UL1449, the document the strips are tested to.

Things get even MORE complicated with "sophisticated" surge strips like the Isobars, that have
common-mode chokes (inductors) in them as well.

Sorry, I'm not spending 2 weeks to write this up so some will panic, some will not believe me
anyway, most will shrug and daisy-chain.

Paul S.