Consulting-Specifying Engineer - September 2007 - (Page 60)

Codes & Standards Grounding and bonding (Article 250) • 250.8: Connection of grounding and bonding equipment. This existing subparagraph modifies and clarifies the permissible means of connections of bonding equipment by adding a list of permitted and not permitted means of connection. • 250.14: Continuity of grounded conductor. This is a new subparagraph added to prohibit using a metallic enclosure, raceway or cable to maintain the continuity of a grounded conductor. Wiring methods (Article 300) As for wiring methods and materials, there were some clarifications and additions to chapter three, including: • 300.10: Adds a new exception such that conduits in the bottom of open-bottom equipment such as switchboards, motor control centers and transformers no longer have to be mechanically secured to the equipment. • 300.50(f): Adds a subparagraph requiring a warning ribbon over direct-buried cables that are more than 600 volts. Conductors for general wiring (Article 310) • 310.15(B)(2)(c): This section adds a new subparagraph to address where conductors or cables are installed in conduits exposed to direct sunlight on rooftops. These must have ampacity corrections made for increased temperature inside the conduit. This ampacity correction is to be made so that conductors or cables used in these locations will not exceed their designated operating temperature. Receptacles, cord connections and attachment plugs (Article 406) Significant changes to be aware of have occurred in Chapter 4 under Article 406 and Article 408: • 406.8: Receptacles in wet or damp locations will be required to be listed for damp or wet locations, not just the enclosure. It will become effective on Sept. 1, 2011, in order to give manufacturers time to develop the devices. • 406.11: A new subparagraph has been added that requires 15-amp and 20-amp receptacles in a dwelling unit to be tamper-resistant. Switchboards and panelboards (Article 408) • 408.4: This section has been revised to include the requirement to identify spare overcurrent devices on the circuit directory. • 408.35: Number of overcurrent devices on one panelboard. The paragraph in the 2005 edition has been deleted and so has the limitation of 42 poles. The revised NEC will limit the number of devices in a panel to what has been designed and listed for. AERCO. Dominating the high-efficiency game. We’ve been the technology leader for decades — long before everyone else started joining the high-efficiency game. When it comes to innovation, no one beats us no one even comes close. For 300,000 to 3 million BTU/H condensing boilers with unmatched turndown for exceptional thermal efficiency, or for long-lasting, easy-to-maintain, indirect-fired water heaters with BAS-ready electronic controls, make the winning move to AERCO. Get the score at www.aerco.com/game2 Heat You Can Bank On Copyright 2006 AERCO International, Inc. Input #233 at csemag.com/quickResponse 60 Consulting-Specifying Engineer • SEPTEMBER, 2007 http://www.aerco.com/game2 http://www.aerco.com/game2 http://csemag.com/quickResponse

Table of Contents Feed for the Digital Edition of Consulting-Specifying Engineer - September 2007

Contents M/E Roundtable Cover Story: Airborne Superbugs Third-Party Liability Back to School Product Spotlight Codes & Standards Professional Practices How To New Products Jobs/Cliassifieds Specifier’s Notebook Pure Power Supplement New Technologies, Same Old Transmission Problems Wireless Battery Recharging Solar Concentration Renewables Tracking System A Mighty Wind The Importance of Load Bank Testing Quality Power for Security Systems

Consulting-Specifying Engineer - September 2007

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