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  6. 250 A 120/208 V 4-Pole eSTS

250 A 120/208 V 4-Pole eSTS

LayerZero® eSTS keeps mission-critical loads online by transferring between sources in < 4 ms, using fiber-optic based control logic and a voice-guided bypass procedure that reduces operator error. Designed for maximum uptime in mission-critical data centers. Fully serviceable from the front in a 48" x 36" x 90" footprint.

Rating 250 A
Voltage 120/208V
Poles 4-Pole
Transfer < 4 ms
Service Access Front-Only
Fiber-Optic Controls
Signal paths immune to EMI/RFI
UL 1008S / ETL Listed
Verified transfer performance
Machined Hardware
Connections maintain clamp force over life
Seismic AC156
Shake-table tested
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Black Finish
Gray Finish

Features and Benefits

High-speed transfer
High-Speed Transfer
< 4 ms
4-pole switching
4-Pole Switching
Solidly switched neutral
Convection cooling
Convection Cooling
Physics-Driven Reliability
Waveform capture
Waveform Capture
See real-time events
Front-only install
Front-Only Install
No rear or side access required
VDAT plotting
VDAT / ITIC
Disturbance analysis
Seismic rating
Seismic AC156
Shake-table tested
Touchscreen guided bypass
Touchscreen UI
Voice-guided bypass

Compact Footprint. No Side or Rear Access Required.

250 A 4-Pole eSTS cabinet showing 90-inch height, 48-inch width, and 36-inch depth footprint 250 A 4-Pole eSTS cabinet with front-only access doors and integrated touchscreen LayerZero eSTS touchscreen displaying system status and bypass controls

Specifications

Copy Specs into email / Excel

Electrical Specifications

Current250 A
Nominal Input Voltage120/208 V
Nominal Output Voltage120/208 V
Poles4

Mechanical Characteristics

Height90 in (2286 mm)
Width48 in (1219 mm)
Depth36 in (914 mm)
Weight1350 lb (612.3 kg)

Documents & Downloads

Static Transfer Switch power system one-line diagram icon showing phase and neutral switching
One-Line Diagram

A one-line diagram is a symbolic representation of three-phase electric power systems, depicting the paths for power flow between entities of the power distribution system.

Outline icon representing a static transfer switch used in mission-critical power systems
Product Outline

A product outline is a technical engineering drawing showing mechanical characteristics of our products.

Guideform specifications icon representing technical requirements for mission-critical power equipment
Guideform Specification

Guideform specifications include the requirements, specifications, and considerations of installing LayerZero equipment.

LayerZero Power Systems brochure cover for mission-critical power solutions
Product Brochure

Product brochures contain information about the product's features, benefits, and specifications.

Fast, Reliable Transfers

Switch to S1
Switch to S2
Tap a source to simulate transfer between redundant feeds.

Automatic Source Transfer in <4 ms

eSTS continuously monitors both sources and instantly moves the load when instability is detected. Transfers occur without contact welding or nuisance trips.

Fiber-optic control paths and triple modular redundancy protect continuity even during upstream events.

  • < 4 ms typical transfer time
  • Triple Modular Redundancy (TMR)
  • Fiber-optic signaling
4-Pole Transfer Explained

Unlike 3-pole systems, the 4-pole eSTS switches the neutral conductor as well as all phases. This ensures precise isolation between sources, eliminating circulating currents and neutral potential differences - critical for sensitive IT loads and transformer-isolated systems.

360° Spin

Manufacturing & Quality Assurance

  • Automated machining & robotics
  • Serialized tracking of every critical board
  • 100% end-of-line testing
  • Vertical integration for consistent quality

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