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To assist you in understanding the new standard, this document contains answers to commonly asked questions. It explains how Strikesorb® surge suppression technology conforms to the new standard without compromise to its patented, fuseless design, and explains how Strikesorb maintains its outstanding surge suppression performance even in the most demanding application environments.
Q. Why did Underwriters Laboratories (UL) revise the 1449 standard?
A. UL revises its standards as a result of the industry’s
awareness of potentially dangerous failure modes
of UL listed or recognized products available in the
market. Reported catastrophic failures of surge
protection systems derived an initiative at UL to revise
its UL 1449 2nd edition safety standard. Effective
February 9, 2007 all UL listed or recognized surge
protection devices sold in the market must meet the
revised testing requirements of the standard.
Q. What are the main changes in the UL 1449
2007 revision?
A. In 1998, the UL 1449 2nd edition standard became
effective with special provisions to address the “slow
burn” or “thermal runaway” failure mode of surge
protection devices, responsible for catastrophic events
which could compromise the safety of electrical
installations. In its 2007 revision, the UL 1449 standard
extends the limit of the abnormal overvoltage short
circuit current tests from 5 Amps to 1000 Amps with
test duration of up to seven hours.
Q. How does the Strikesorb module perform
against the new testing requirements of the
revised UL standard?
A. UL testing requires that surge protection modules
withstand test conditions with available short circuit
currents up to 1000 Amps for seven hours. Strikesorb
surge protection modules are UL recognized
components and fulfill the new test requirements
without being disconnected from the testing circuit.
Strikesorb modules remain connected for the full
seven hour period, conducting the 1000 Amps,
successfully dissipating the thermal energy created
in the modules, and maintaining their safe operation.
This is due to the robustness and the unique
mechanical design of Strikesorb modules.
Q. How do other technologies pass the new UL
testing requirements?
A. Other technologies rely on thermal and overcurrent
fusing to comply with the revised UL standard
requirements. The use of disconnects inside surge
protection systems is not a new idea. Existing surge
protectors complying with the current (1998) revision
of UL 1449 use fuses and thermal disconnects to
meet the UL requirements for testing at 5 Amps for
seven hours. When exposed to the test conditions,
these devices actually disconnect from the circuit
within a few seconds. The revised standard (by
introducing new intermediate current testing levels
at 100, 500 and 1000 Amps) makes the design of
the fusing or thermal disconnection mechanism more
challenging. The engineering approach many
manufacturers take is to make the disconnection
mechanism react to these currents very fast in order
to prevent the full amount of the current (100, 500,
and 1000 Amps) from passing through the device.
However, a more sensitive disconnect makes the
surge protectors more vulnerable to failures from
surge currents. The end result is a compromise in
the protection levels these devices will be offering.
Strikesorb, by not relying on fuses or thermal
disconnects, does not suffer from this engineering
compromise.
Q. What does safety mean to a surge protection
system?
A. A surge protection system should never become
a safety hazard to the protected equipment, personnel or the establishment in which it is installed. Explosions,
fires, smoke or soot emission are absolutely
unacceptable. The role of a surge protection system
is to secure the reliability of an installation and not to
compromise it. Improperly engineered protectors cost
the customer much more than their own replacement
cost. A surge protection failure may result in damages
to critical systems and contribute to the operational
budget expenses due to incremental costs for
cleaning, decontaminating and/or equipment
replacement. One always needs to make sure that
the products are UL listed (for TVSS stand-alone,
permanently connected panels) or UL recognized
(for surge protection components) and meet the
requirements of the latest revision (Feb. 9, 2007) of
the UL 1449 standard. UL (www.ul.com) keeps files
of all listed products and recognized components
and provides the manufacturers with reports for the
compliance of their products to the standards. Ask
for this information.
Q. How can I make sure that when I purchase
surge suppression systems, the products deliver
what they promise?
A. It should be noted that UL listing ensures that the
device meets the testing requirements of the standards
organization. It does not mean that the device meets
the surge suppression capabilities promoted by the
manufacturer. Surge ratings quoted for the surge
protection device are most often calculated and
not proven. For example, there are products that
are rated at 250 kA but fail at a fraction of this level.
It is always prudent to ask for test reports from
independent laboratories that prove that the surge
rating claims of the product are met in practice
according to the procedure described in the NEMA
LS-1 standard. Manufacturers who respect their
customers will have these reports immediately
available.
Q. How long has the Strikesorb been in the
market?
A. Strikesorb was introduced to the market in 1999
and since then more than quarter of a million modules
have been installed throughout the USA, Canada,
Central and South America, Africa, Europe and
Southeast Asia. Customers using the Strikesorb
technology include wireless and wireline
telecommunication companies, large industrial
groups, OEMs, civil aviation authorities, mining and
oilfield services companies, windmill farm operators
and high end residential users.
Q. What are the main advantages of the
Strikesorb technology?
A. Strikesorb is a unique overvoltage and surge
protective device. It provides low clamping voltages
at surge currents up to 200 kA, with unparalleled
robustness and reliability. It guarantees safe operation
and, due to its patented design, it eliminates
explosions, fires and catastrophic failures common
to many surge suppression products available in the
market. It does not contain internal fusing, thermal
or otherwise, and provides continuous protection to
the load. Its design lends itself to easy integration in
larger electrical systems to provide the best protection
possible and eliminate the need for long connection
leads. Furthermore, it is absolutely maintenancefree,
contributing to significant operational savings
for the installation.
Q. How can Strikesorb be used in the industry?
A. Strikesorb modules can be used either within
stand alone TVSS systems or as surge and
overvoltage protection modules integrated inside
larger power systems where overvoltage and surge
protection is required by the end customer or by the
system manufacturer or integrator as an added value
feature. Integration offers the best possible option
due to the reduction or elimination of the connection
lead length.
Q. What does Strikesorb offer to the customer
in summary?
A. Strikesorb technology offers system integrators
and end users the ultimate maintenance-free
overvoltage and surge protection, coupled with
safety, reliability and versatility. For more information
on Strikesorb TVSS please visit www.rayvoss.com.
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