My question really stems from some research I am doing on surge protection devices. (SPD) Most consumer level uninterruptible power supplies / battery backups (UPS) provide some level of surge protection, but according to what I have read, it is not the best protection. It would then seem best to plug a UPS into a quality surge protector. However, some individuals say that that can cause one or both to fail. The stated reason is that " you cannot put MOV's in a series, and that is what you are essentially doing when you plug a UPS into a SPD. This would be the same as plugging one surge protector into another. "
There seems to be some misinformation about this, as a bulletin from Eaton Corp. recommends putting a surge protector upstream of your UPS. The following sums it up.
...any overflow of juice on the power line will be attracted to the MOVs (generally three MOVs to a protector) and drawn to a ground area. The rate at which electricity flows is enough that this can bounce between the two surge protectors, negating any and all protection and even cause some models to shut down.
There seems to be some misinformation about this, as a bulletin from Eaton Corp. recommends putting a surge protector upstream of your UPS. The following sums it up.
...... So why
not fully protect the equipment connected to the UPS,
and the UPS itself, from the damaging effect of voltage
transients by installing the most effective surge protec-
tion system possible?
Is the surge protection provided by a UPS adequate?
The answer is NO! The surge protection provided by
most UPS units is limited, and often does not contain
EMI/RFI filtering, which lowers the let-through voltage
provided by MOVs alone.
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