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Instruction Booklet
IB0162063EN
Effective January 2014
O & M Manual for the EGS Metered, Service
Entrance Automatic Transfer Switch with Relay Control
Eaton Corporation www.eatoncanada.ca
1.2 General Information
ATSs are used to protect critical electrical loads against loss of
power. The load’s utility power source is backed up by a generator
power source. An ATS is connected to both the utility and generator
power sources and supplies the load with power from one of these
two sources. In the event that power is lost from the utility power
source, the ATS transfers the load to the generator power source.
Once the utility power is restored, the load is automatically trans-
ferred back to the utility power source (Figure 2).
Figure 2. Typical Load Transfer Switch (Contactor) Schematic.
An intelligence system initiates the transfer when the utility power
source fails or falls below a preset voltage. An engine start is then
initiated by the generator and the ATS transfers to the generator
power source when sufficient generator voltage is available. When
the utility power source is restored, the ATS automatically transfers
back and the generator will shut down after a time delay. In the
event the utility power source fails and the generator power source
does not appear, the ATS remains connected to the utility power
source until the generator power source does appear. Conversely, if
connected to the generator power source and the generator power
source fails while the utility power source is still unavailable, the
ATS remains connected to the generator power source.
ATSs automatically perform the transfer function, and include three
basic elements.
1. Main contacts to connect and disconnect the load to and from
the source of power.
2. Solenoids to make the transfer of the main contacts from source
to source.
3. Intelligence/supervisory circuits to constantly monitor the condi-
tion of the power sources and thus provide the intelligence nec-
essary for the switch and related circuit operation.
1.2.1 Design Configuration
Utility
Generator
Load
The Eaton Metered, Service Entrance Rated, Automatic Transfer
Switch is a rugged, compact design that combines a meter socket,
service entrance rated disconnect, and ATS all in a single enclosure.
The design provides for both top or bottom entry service cabling
to the meter socket. A factory wired 100 or 200A circuit breaker
provides a Canadian approved service entrance rated disconnect
means. The ATS is controlled by an Eaton relay controller and uti-
lizes power contactors to transfer essential loads from one power
source to another (see Figure 3). The switch’s design uses suitable
mechanical and electrical interlock switches to eliminate the possibil-
ity of connecting the utility service to the generator output. In addi-
tion, a manual override lever is provided for the transfer function.
Warning
DO nOT ManUaLLY TranSFEr THE SWiTCH WHiLE UnDEr LOaD.
Figure 3. EGSC100AMSE (100 A).
