Zenith ZTSM& ZTGM0 pages

GE Energy
Digital Energy

Zenith ZTSM & ZTGM
Manual Transfer Switches

Introduction
Some emergency power installations require multiple
automatic transfer switches, each feeding a specific
load. In many installations where non-critical loads
are being served, specifications may call for manual
or non-automatic transfer switches. This method is
used because operating personnel are present and the
loads are not of a critical nature requiring unattended
automatic operation.
Because of the less critical function of this equipment,
no specific industry requirements have been established.
As a result, devices such as double throw disconnect
switches have been used. Since the non-automatic
transfer switches are part of the emergency power
supply system, they should have the same UL 1008
electrical ratings as the automatic transfer switches
feeding critical loads. In the event of a short circuit, the
non-automatic transfer switches must have the same
withstand current ratings as the automatic transfer
switches and they must be as rugged and dependable.

Features and Benets
To meet this need, GE has developed the Zenith ZTSM
and ZTGM Series electrically operated, mechanically held
non-automatic transfer switches. These units feature the
same construction as the Zenith ZTS and ZTG Series
of automatic transfer switches and are supplied with
the same electrical ratings and mechanical features. The
manual series is electrically operated by means of push
buttons mounted on the switch enclosure or at a
remote location. Unlike the above mentioned handle-

operated disconnect switches, the Zenith ZTSM and
ZTGM Series offers additional protection by incorporating
Source 1 and Source 2 voltage sensing relays which
will not permit the switch to be manually transferred
unless the source to which it is being transferred is at 90%
of its rated voltage. In addition, the Zenith ZTSM and ZTGM
Series are tested and listed per UL 1008 standards.
Manual handle-operated, double throw disconnect
switches are not listed to this critical standard.