Vertiv Liebert STS2 - 2.0 LOCATION CONSIDERATIONS; 2.1 Recommended Minimum Service Clearances

Vertiv™ Liebert® STS2
SL-20610_REV12_09-21 5 Guide Specifications
Proprietary and Confidential © 2021 Vertiv Group Corp.
1.4.5 Reliability
MTBF
The Vertiv™ Liebert® STS2 shall be designed for high reliability and high availability with an MTBF
exceeding 1,000,000 hours. To the fullest extent practical, redundant circuits and components shall be
used to eliminate single points of failure.
Power Supply
Redundant power supplies shall be provided to prevent any single-point power supply failure mode. The
Liebert® STS2 shall have two completely separate power supplies mounted on separate boards so a
power supply can be replaced while the load is on bypass. There shall be two separate DC buses, one
from each power supply, to provide redundancy throughout the controls.
Logic
Control logic shall be triple-redundant. Each of the three logic modules shall have its own separate power
connection to each power supply bus. Each logic module shall be fused to prevent it from shorting the
power supplies if an internal failure occurs. Gating and control logic shall be partitioned so that the failure
of one source’s gating or sensing logic does not prevent the switch from transferring to the other source.
Components
All electrical components requiring normal maintenance or repair shall be replaceable without de-
energizing the load, assuming that at least one source is available. Solid-state switching devices shall be
packaged to allow safe repair of the switching devices without having to de-energize the load. All MCSs
shall be of a plug-in or draw-out type to allow replacement without de-energizing the load. All control
and logic components shall be mounted separate from the power components.
Fuseless
No fuses are used to protect the solid-state power switching devices.
Access
The Vertiv™ Liebert® STS2 shall be designed for front access only. The Liebert® STS2 shall be designed
so all installation, repairs and maintenance can be done from the front or top of the unit. The Liebert®
STS2 shall be designed to minimize the exposure of hazardous voltages to allow safe servicing of the
unit while the load is energized. Barriers shall be used on and around customer connections to protect
personnel during maintenance.
1.5 Documentation
1.5.1 Equipment Manual
The manufacturer shall furnish an installation, operation and maintenance manual with installation,
startup, operation and maintenance instructions for the specified system.
1.5.2 Proposal Submittals
Submittals with the proposal shall include:
• A system one-line diagram.
• Outline drawing including weights, dimensions, heat dissipation and recommended service
clearances.
• Location and detailed layouts of customer power and control connections.
• Description of equipment to be furnished, including deviations from these specifications.