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    May 15, 2024

    Portable Power Safety- Point of Use – Power Distribution Units

    Jobsite portable power safety, especially Point of Use, is critically important. Given the work environment, temporary power cords strewn about the site, cord damage and resulting injury are a real concern. Thousands of workers are injured or killed annually on Jobsites with temporary power. The National Electrical Code, NEC 590 and other safety bodies, NFPA 70E and OSHA 1926, have developed safety standards to ensure safe jobsite power.

    This Blog Post focuses on three areas of importance.


    GFCI – Ground Fault Circuit Interrupter technology. GFCI’s measure the imbalance between the hot and neutral conductors in an AC electrical circuit. GFCI’s protect users by opening the electrical circuit in nanoseconds when it senses this imbalance – for example a person holding a damaged cord and a part of their body touching a grounded surface completing the circuit through the human body is shocked or electrocuted.


    UL943-5th Edition outlines self-testing GFCI’s technology, incorporated in standard GFCI Receptacles and required a decade ago. On May 5, 2021, the same requirement for self-testing now includes GFCI/Open Neutral protection modules used in temporary power applications, Spider Boxes, etc.


    Why is this important? - Self-Testing GFCI circuitry, as the name implies, monitors GFCI circuity several times a minute to ensure it will function properly when called upon. Jobsites are especially susceptible to power surges, moisture, dirt and miswiring, the self-testing circuity makes sure the module operates safely.


    UL1640 Build Requirements and Open Neutral Protection. This standard is critically important to a proper system “build” as well as open neutral protection in the event a neutral conductor is cut. First, let us discuss “build security.” Build security is a term used to regarding portable power systems built properly ensuring electrical safety. Temporary power components are often built by others without proper attention paid to safety – “its temporary after all.” UL1640 states that builders and assemblers of electrical systems follow specific build and wiring practices along with approved components to ensure safety. The fact that an electrical temporary power assembly is built using UL approved products does not mean the final assembly meets compliance requirements.


    Working together for safety – Self-Testing GFCI’s and Open Neutral Protection – jobsites strewn with extension cords and feeder cords are especially susceptible to damage. UL1640’s requirement for open neutral protection ensures that if the neutral conductor is cut or damaged, the circuit will open. This is important since a standard GFCI receptacle has a mechanical latching system and will not open with a power loss. The open neutral protection ensures that if there is a power loss or open neutral, the relay will drop out removing the shock potential from a power conductor. Ericson’s GFCI Module (1075-AR module) incorporating both UL943-5th edition self-testing GFCI and Open Neutral protection, is ruggedly built for these applications making it an infinitely safer, more reliable option, especially around damp areas and jobsite radio interference.


    This same technology is used in Ericson Spider Boxes (Ericson 1066FS). Other units might use individual GFCI’s with open neutral relays – (Ericson CDU50 series).  And this technology is used in our In-Line GFCI Cordsets.


    Learn more about Ericson’s temporary power systems by clicking here –Jobsite Power & Protection - Power Distribution Units


    Brian Earl

    Hailing from Minnesota originally, Brian began his secondary education at the University of Minnesota with his undergraduate work and his MBA in Management at University of Michigan, focusing on strategic marketing and market planning. He has an extensive background in developing and leading a variety of marketing,...

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