Specifications
February 2007
16-24
For more information visit: www.eaton.com CA08101001E
Transfer Switches
16
Transfer Switch Equipment
Bypass Isolation Transfer Switch
Bypass Isolation
Transfer Switch
Bypass Isolation Transfer Switch
Product Description
A bypass isolation switch utilizes
loadbreak isolation and bypass transfer
power contacts. Thus, should voltage
be lost on the line to which the ATS
is connected, and should a manual
bypass be required to the other line,
this can be accomplished safely and
quickly as described below. With con-
tactor designs utilizing non-loadbreak
isolation and bypass switches, manual
bypass to the other line is hindered
by mechanical or electrical safety
interlocking.
Application Description
The bypass isolation switch is designed
for applications where maintenance,
inspection and testing must be per-
formed while maintaining continuous
power to the load. This is typically
required in critical life support systems
and standby power situations calling
for safe system maintenance with no
power disruptions. Such a design allows
for the quick removal of the different
switching devices for inspection,
maintenance or replacement.
Features, Benefits
and Functions
The Eaton transfer switch is a rugged,
compact design utilizing Magnum
power switches or Magnum power
circuit breakers to transfer essential
loads from one power source to
another. Open transition switching
devices are interlocked to prevent both
switching devices from being closed at
the same time. The versatile design, in
addition to standard transfer functions,
offers an optional integral thermal and
short circuit protection in either or
both switching devices.
The switching devices are in a compact
vertical arrangement. The logic can be
easily disconnected from the switch-
ing device without disturbing critical
connections. The enclosure is free
standing, and, by using the specially
supplied cleats, the switch is seismic
approved (Option 42). The terminals
are mounted in the rear of the switch,
permitting rear, top, bottom or side
cable or bus bar entrance.
The switching devices have a high
withstand rating. The high-speed,
stored-energy switching mechanism
guarantees a transfer time of less than
3 cycles.
Features
■ Reliable microprocessor logic.
■ Designed to safely withstand fault
currents.
■ Eliminates need for complex
interlocks.
■ Most versatile bypass isolation
transfer switch available.
■ Cutler-Hammer drawout cassette
design.
■ Overcurrent protection available.
■ No loadbreak when bypassing to
the same source.
■ Drawout capabilities on both ATS
and Bypass portions.
■ Compact design.
■ Ability to test power switching
elements during drawout process.
■ Power switching devices completely
interchangeable between ATS and
Bypass portions.
Standards and Certifications
Eaton transfer switch equipment is
listed for application by UL and CSA.
In addition, Eaton ATSs are listed in
File E38116 by Underwriters Laboratories
under Standard UL 1008. This standard
covers requirements for ATSs intended
for use in ordinary locations to provide
for lighting and power as follows:
A. In emergency systems, in accor-
dance with Articles 517 and 700 in
the National Electrical Code (NEC),
American National Standards
Institute/National Fire Protection
Association (ANSI/NFPA) 70 and
the NFPA No. 76A and/or
B. In standby systems, in accordance
with Article 702 of the NEC and/or
C. In legally required standby systems
in accordance with Article 701 of
the NEC. Eaton ATSs are available
to meet NFPA 110 for emergency
and standby power systems, and
NFPA 99 for health care facilities
when ordered with the appropriate
options. Since Eaton ATSs utilize
specially designed switches and/
or switching devices as the main
power switching contacts, these
devices must also be listed under
the additional UL Standard 1066.
UL utilizes two basic types of list-
ing programs:
a) Label Service and b) Re-exami-
nation. UL 1066 employs a
label service listing program
which requires an extensive
follow-up testing program
for listed devices. Standard
UL 1008 for ATSs lists devices
under the re-examination
program which only requires a
continual physical re-examina-
tion of the components used in
the product to ensure consis-
tency with the originally
submitted device. Follow-up
testing IS NOT required by
UL 1008. Representative pro-
duction samples of switches
and switching devices used in
Eaton ATSs are subjected to a
complete test program identi-
cal to the originally submitted
devices on an ongoing periodic
basis per UL 1066. The frequency
of such a re-submittal can be as
often as every quarter for a low
ampere device.
Note: IBC seismic qualified.