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US Electrification
LoadGuard™ MSU
Industrial Solutions

LoadGuard™ MSU

LoadGuard™ MSU (Modular Series Unit) is engineered for hard-wired installation within or adjacent to electrical loads such as outdoor lighting, robotics, process automation systems, motors, HVAC systems, pumps, heaters, programmable logic controllers and other point-of-use applications. Compact and powerful, the LoadGuardTM MSU protects these and other individual components from damaging electrical transients, high-frequency noise and high energy disturbances. LoadGuardTM provides 50 kA of surge protection for loads up to 24 A.

Surge current protection

Parallel MOV Arrays: LoadGuard products employ MOVs in parallel arrays placed at the input and output terminals to protect critical loads from high-energy transient damage. MSU surge current capacity is 50 kA per mode.



  • Series-connected design
  • Compact footprint/easy installation
  • High frequency noise filtering



  • Recognized to UL 1449 4th Edition as a Type 2 compliant assembly
  • Rugged, nonmetallic enclosure
  • Component level fusing
  • Status indicator light


Technical specifications

  • Maximum Surge Current Rating 50kA Per Mode
  • Voltage (Single-Phase Applications) 120, 220 or 277
  • Voltage (3-Wire + Ground Applications) 220/380 or 277/480
  • Voltage (Split-Phase Applications) 120/240


Standards and certifications

  • Listed by ETL to UL 1449 4th Edition, Type 4 for Type 2 SPD applications,  cUL and UL 1283
  • Compliant to IEEE C62.41.1-2002, C62.41.2-2002 and C62.45-2002
  • NFPA 70 [NEC], Article 285
  • RoHS Compliant
  • CE, IEC 61643-11-2011
  • EMC Directive 2004/108/EC
  • Low Voltage Directive 2006/95/EC



  • Outdoor lighting
  • Robotics
  • Process automation systems
  • Motors
  • HVAC systems
  • Pumps
  • Heaters
  • Programmable logic controllers
  • Other point-of-use applications


Downloadable Resources


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