CSE Pure Power - Summer 2008 - (Page 38)

❯❯ PURE POWER // SUMMER 2008 38 switchgear story able to allow the vented hot gases to cool before reaching personnel, special ducting is required to remove the gases from the equipment room. The speed with which the electromechanical switch must close in order to prevent arc duration and the resultant heat and pressure buildup is substantial. IS IT NECESSARY? Though ANSI/IEEE C37.20.7-2007 was expanded to include all types of low- and medium-voltage switchgear, it might be surprising to learn that arc-resistant construction may not be necessary for all applications. Keep in mind that a facility owner’s most important priority is protecting his employees and anyone who works nearby the switchgear. If the equipment is behind a locked door, personnel likely won’t be present if there is an arc fault, thus decreasing the chances they’ll be hurt. The best rule of thumb for an industrial facility owner considering arcresistant construction for new switchgear is to review current processes and work ﬂow (or anticipated, in the case of a new facility). For example, arc-resistant construction is highly recommended for the following situations: If the switchgear is on the manufacturing ﬂoor, near machinery and personnel, or in close proximity to highly traveled or frequented areas, like a lunch room or break room If a facility does not have switchgear redundancy In an equipment room where routine access is acceptable for monitoring or controlling equipment. MAKING THE CHOICE Arc-resistant switchgear is never a replacement for personal protective equipment (PPE) as described in the National Fire Protection Assn.’s NFPA 70E 2004 “Standard for Electrical Safety in the Workplace.” Though ANSI/IEEE C37.20.7-2007 speciﬁcally does not cover personnel working in, on, above or below switchgear, it may be tempting for an electrical worker to forgo PPE because he knows the equipment has a vented sheet-metal enclosure or an active fault mitigation system. Put simply, this is not a safe work practice, and a facility owner or manager must discourage this behavior. But what arc-resistant switchgear can provide is cost management—an arc fault event that is averted due to an active fault mitigation system can prevent a major capital expenditure for new switchgear, or lost business due to processes that have to be halted because power simply isn’t available. That also doesn’t begin to cover the potential healthcare and litigation costs due to worker injury. For more info, enter #416 on the Reader Service Card http://www.mtecorp.com http://www.mtecorp.com

Table of Contents Feed for the Digital Edition of CSE Pure Power - Summer 2008

CSE Pure Power - Summer 2008 Contents In the News Industry Roundup Risk Assessments for COPS Grounding Requires More Power Systems to Protect Healthcare Important Changes Coming in NFPA 70E A Look at Arc-Resistant Switchgear Agencies and Associations New Products Ad Index

CSE Pure Power - Summer 2008

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