Permanent Electrical Safety Devices Will Verify Zero Electrical Energy IEEE.cdr

– Article 120.1 of the NFPA 70E establishes the procedure for creating an electrically safe work condition. Since this was written, the day-to-day practice of electrical safety has changed going beyond the precise language of Article 120.1(1-6). This is due to the increased usage of permanent electrical safety devices (PESDs) in Lock-out/Tagout procedures. The relatively new concept of permanent electrical safety devices actually improves the workers’ ability to safely isolate electrical energy beyond that which was originally conceived when Article 120 was written. PESDs go beyond the high standard, yet they still adhere to the core principles found in Article 120.1. With PESDs incorporated into safety procedures and installed correctly into electrical enclosures, workers can transition the once-risky endeavors of verifying voltage into a less precarious undertaking that never exposes them to voltage. Since, every electrical incident has one required ingredient – voltage, electrical safety is radically improved by eliminating exposure to voltage while still validating zero energy from outside the panel. Index Terms -– Voltage detectors, voltage portals, non-contact voltage detector, NCVD, power warning alerts, permanent electrical safety devices, voltage detector validation procedures, verification, voltmeters Introduction To employees all safety – especially electrical safety – is personal. Little else matters to them unless electrically safe work conditions can be created and maintained through their work environment. Article 120.1 of the NFPA 70E was, as its title suggests, penned with the important purpose of establishing the “gold standard” for creating an electrically safe work condition. Since then, however, innovation in the realm of electrical safety has surpassed the precise language of Article 120.1(1-6) because it does not speak directly to the value permanent electrical safety devices have in achieving an electr ical ly safe work environment. The relatively new concept of permanent electrical safety devices (PESDs) actually improves the workers’ ability to safely isolate electrical energy beyond that which was originally conceived when Article 120 was written. The forward-thinking concept of PESDs goes beyond the high standard of safety for which competent companies strive, yet they still adhere to the core principles found in Article 120.1. With PESDs incorporated into safety procedures and installed correctly into electrical enclosures, workers can transition the once-risky endeavor of verifying voltage into a less precarious undertaking that never exposed them to voltage. Let’s face it; every electrical incident has one required ingredient – voltage. Electrical safety is radically improved by eliminating exposure to voltage while still validating zero energy from outside the panel. The standard shoulder belt you (hopefully) use each time you are in a vehicle is an improvement on a simple lap belt found in many vehicles of the past. American car manufacturers offered seat belts only as options until Saab introduced them in 1958 as a standard safety element – an act that changed the landscape of passenger safety in vehicles. Later, driverand passenger-side airbags offered breakthrough safety advances beyond the then-simplistic seatbelt only to later be enhanced by side-impact airbags. Each of these safety innovations relies upon each other for peak functionality and Permanent Electrical Safety Devices Will Verify Zero Electrical Energy Philip B Allen Grace Engineered Products, Inc. Davenport, IA, 52807, USA September 2011 [email protected] ? Powered from the line voltage (no batteries) Applies to any power system by operating on a wide voltage range (40-750VAC/301000VDC) ? Cat IV rated for high surge immunity UL Certified to UL 61010-1 as per NFPA 70E 120.1(5) FPN Written Procedures and Training: Using PESDs in an electrical safety program requires written Lock-out/Tag-out (LOTO) procedures. Employees need to be trained and have access 2 to these procedures. What does it really mean and what happens when it’s validated? An electrically safe work condition requires 100% accuracy from voltage detectors. To ensure this, the NFPA 70E says, “Before and after each test, determine that the voltage detector is operating satisfactorily,” (NFPA 70E 120.1(5). In order to comply, electricians first check their voltage detector to an independent voltage source (i.e. a nearby 120VAC outlet). Next, they check for zero voltage on the primary source. Work begins only after the voltage detector is rechecked to the independent live voltage source. This straight-forward validation procedure works for a portable voltage detector because it can be physically moved between two voltage sources. The authors of NFPA 70E only considered the portable voltage detector (i.e. voltmeters) when writing Article 120.1, and by surpassed conventional safety protocols of 1958. Airbags provide little protection if drivers are not wearing seatbelts; shoulder belts without lap belts are ineffective, and side airbags alone are insufficient. These safety reformations, when used in conjunction with each other, raised the expectations of safety for all users and ultimately manufacturers began offering them as standard equipment. Similarly, PESDs are revolutionizing electrical safety and should be used in conjunction with existing safety practices. 1 Definitions and Resources: Non-Contact Voltage Detector (NCVD): A battery–operated voltage detector that senses voltage without actually touching an energized conductor. Voltage Portal: Extends a voltage source to the outside of an electrical enclosure in an encapsulated non-conductive housing designed for a NCVD to sense voltage if placed into the voltage portal (Fig. 1). Voltage Indicator: A hardwired LED indicator permanently wired to the phase(s) and ground that illuminates when a 40VAC/30VDC or greater voltage deferential exists between two lone inputs. Typical 3-phase/4-wire voltage indicator requirements include (Fig 2): Permanent Electrical Safety Devices Will Verify Zero Electrical Energy September 2011 Page 2