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With
the recent proliferation of low-cost standby UPS products which
claim to "solve all the AC power problems", a false sense of security
seems to exist among users who purchased and installed these basic
non-isolated UPSs for their PCs, fileservers, network/telecommunication
equipment, point-of-sale terminals, etc.
Such a false sense of security and confidence is often rudely
challenged by equipment glitches, crashes, and malfunctions that
persist even after installation of these non-isolated UPS products!
The answer to this unexplainable failure of UPS to provide 100%
protection against AC power problems can be found in an "Isolation
Transformer" based UPS or Line Conditioner.
Experienced electrical engineers have known this limitation of
non-isolated UPSs, line conditioners, surge protection devices
and EMI/RFI noise filters for a long time - and their answer has
been a "dedicated circuit" which is a separate AC wire run all
the way to the main electrical panel located next to the building’s
power transformer. Since the high neutral line voltage and high
levels of spikes and transients are caused by devices such as
air conditioners, heaters, elevators, copiers, laser printers,
etc., bypassing all the sub-panels that feed these "dirty" devices
by installing and using a "dedicated circuit" usually solved the
problems!
However, installation of a dedicated circuit can be very expensive
and time-consuming, especially when it is a large or high-rise
building. Installation of a dedicated circuit also requires an
approval and permit from a licensed professional engineer (PE.),
the building wiring diagram and the final drawing and work must
be inspected and approved by a local county or city electrical
inspector. The cost of a single dedicated circuit can be several
thousand dollars and may require several weeks (or months) from
start to finish.
The high cost and long installation time of installing a dedicated
circuit can be eliminated by using an ISOLATION LINE CONDITIONER
or ISOLATION UPS system, however. Because of the integral isolation
transformer, each isolation line conditioner or UPS qualifies
as a "Separately Derived Power Source" under National Electrical
Code 250-5D. Isolation Conditioner and UPS also complies with
the U.S. federal government’s FIPS Publication 94 requirement
of neutral and ground bonding for elimination of any problems
caused by the presence of neutral voltage or common-mode noise/transients.
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