[TenTec] Surge protectors and fuse blowing

[Ken Brown]

> A MOV is far more effective if its located on the line side of any RFI 
> filtering. That's because the the LC RFI filter acts like an integrator 
> and slows the rate of rise and fall of the fast spike, but passes nearly 
> all of the energy at a lower voltage, with a longer duration. And the 
> lowered voltage makes the internal MOV less effective. So a device with 
> RFI filter at the power inlet connector isn't protected as well by any 
> internal MOV.
>   
That makes sense to me. Still I think it is also preferable to have the 
MOV on the load side of a fuse. That way, if the surge has enough energy 
to blow up the MOV, it will also have blown the fuse. Doesn't have to be 
the fuse in the equipment being protected, but it could be if the fuse 
is before the RFI filter. Maybe that is not usually the case?