top banner
Reference Tools

IIS3P SZ (Seismic Zone)

Emergency Inverters

The IOTA IIS3P SZ Series Inverter Systems are UL Listed 3-phase sine wave output inverters designed to provide power to designated emergency lighting fixtures in the event of a loss of normal power. In a power loss situation, the IOTA IIS3P SZ Series will supply 4.8KVA to 50KVA of emergency power from the battery supply at 2ms transfer time. The IOTA IIS3P SZ Series works in conjunction with any lighting load type and is capable for running normally-on or normally-off designated circuits in the emergency mode. The IIS3P SZ Series is ideal for providing emergency power to extensive 120V, 208V, 277V, or 480V lighting arrangements that utilize multiple lamp and fixture types. The IIS3P SZ Series conducts monthly and annual tests for operation readiness and logs the test results for reference as needed. The IIS3P SZ Series is shaker table tested to an SDS level of 2.5g in accordance with ICC-ES-AC-156 procedures. The IIS3P SZ features a durable front-access NEMA Type 1 steel cabinet design and is backed with a standard 1-year warranty.

Input Voltage

120/208VAC or 277/480VAC 3-Phase 4-wire
(Wye configuration)

Output Voltage

120/208VAC or 277/480VAC 3-Phase
(Wye or Delta configuration)



Output Power

4.8kVA - 50.0kVA

Transfer Time

2 milliseconds

Emergency Operation

90 minutes

Load Power Factor Range

.5 lagging to .5 leading

THD (input/output)

<10% / <3%

Input Power Walk-in

Limiting inrush current to <125%,
10 times for 1 line cycle

Synchronizing Slew Rate

1Hz per second nominal

System Short Circuit


Static Voltage

+/- 4% (Load current change)
+/- 4% (Battery discharge)

Dynamic Voltage

+/- 3% (+/- 25% load step change)
+/- 6% (+/- 50% load step change)
recovery within 3 cycles

Inverter Overload Threshold

280% for 12 line cycles, 115% for 10 minutes

Crest Factor


Operating Temp (Inverter)

0° to 40° C

Operating Temp (Battery)

20° to 30° C

Storage Temp (electronics only)

-20° to 70° C

Relative Humidity

< 95%


Maintenance-free Valve Regulated Lead Acid (VRLA)

Audible Noise (standby mode)

45 dba @ 1m


UL 924 Listed
find the UL Mark on this product

*Input +/- 3%, Output in emergency +/- 0.05Hz

Advantages and Features

Product Advantages

  • 3-Phase emergency system with exceptional 97% power efficiency
  • Shaker Table Withstand Testing to an SDS level of 2.5g to meet rigid industry seismic specifications
  • Fast 2 millisecond transfer time allows for uninterrupted operation of all lighting load types
  • Provides full light output in the emergency mode
  • Conducts required monthly and annual tests for operational readiness and logs test, event, and alarm data


  • PWM/IGBT inverter design for optimal switching speed
  • Micro-processor controlled, temperature compensating charger
  • 120/208 or 277/480 Voltage Options
  • Valve Regulated Lead Acid (VRLA) batteries provide long life and are maintenance free
  • Low Battery Voltage Disconnect protects batteries against deep discharge
  • Includes Input Circuit Breaker and Battery Circuit Breaker (24.0KV and above) or Fuse (4.8KVA to 16.7KVA) Protection
  • Output Circuit Breaker options available
  • User Programmable / Password Protected Interface
  • High-Contrast LCD display screen
  • Includes RS232 Serial Communications port
  • Durable steel cabinet design with white finish
  • Forced air cooling only while in the emergency mode with no filter requirement
  • Meets or exceeds OSHA emergency light and power requirements, NFPA70, NFPA101, NFPA111, UBC, and SBCCI
  • Covered by IOTA’s standard 1-Year Warranty on all electronic components and pro-rated warranty on batteries
  • Factory Startup and Training available