NFPA Journal - May/June 2013 - (Page 63)

NFPA2013 The NEC lists requirements for circular raceways, which are enclosed channels of metal or nonmetallic material designed to hold wires or cables. member of the panel that originally accepted, and ultimately denied, the proposal. “People don’t understand our business, and that sets the stage for potential conflicts,” he says, noting that RVs and RV pedestals already have over-current protection devices. The pedestals, he adds, are considered pieces of equipment—not structures— and are incorrectly compared to portable electrical distribution panels used at construction sites and subjected to grounding requirements. Hopkins says installing the necessary grounding rods at RV parks, where the pedestals are numerous, would entail “excessive cost with no additional safety.” Others disagreed with the panel’s final vote, arguing that the pedestals should in fact be treated as structures. Among them was Ron Chilton, chief electrical engineer and state electrical inspector for the North Carolina Department of Insurance in the Office of the State Fire Marshal. Chilton also sits on the code-making panel that accepted, then rejected, the proposal during the comment stage. “In my opinion, I don’t think the panel has the authority to say, ‘We’re not going to require grounding for pedestals,’” he says. The issue pertains to the definition of “structure” found in the NEC, he argues, and to the code’s extensive grounding requirements—neither of which is covered by the scope of the code-making panel. “This is a perfect example of how well our code-development process Photograph: Shutterstock works,” says Bill Burke, NFPA’s division manager for Electrical Engineering. “Everyone heard the arguments, they understood the electrical needs, and the panel decided the issue for now. This was a great debate, and I guarantee that the public inputs that we receive for this subject next cycle—I’m sure we’ll see them again—will be much better because of this process.” Cables and conductors on rooftops The NEC lists requirements for circular raceways, which are enclosed channels of metal or nonmetallic material designed to hold wires or cables. Research has indicated that exposure to direct sunlight might make a raceway hotter than its ambient temperature and compromise its properties, and the code lists temperature values, or “adders,” to the ambient temperature for use mainly by installers that prevent conduit damage at the standard temperature. These values, however, have been called into question because there has never been a verified report of failure of rooftop wiring in a raceway exposed to sunlight, according to panel members. In addition, the Copper Development Association (CDA) wants to increase these values following a series of recent tests by Underwriters Laboratories (UL). Initial tests conducted by UL led to the values listed in the 2011 NEC, but the study didn’t take into account newer forms of raceways. Based on UL tests conducted last year, the CDA submitted a proposal to increase the ambient temperature adjustments on rooftops, but the code-making panel responsible for this information chose to retain the values in the 2011 NEC. Christel Hunter, a director with General Cable, a worldwide wire and cable manufacturer, and NEC panel member, did submit a proposal requesting that an exemption to the adder provision be made for a specific type of insulation. The panel rejected the proposal, but expressed interest in laboratory testing that could substantiate the exemption. Hunter says that testing confirmed high temperatures posed no safety risk to the insulation when it was placed on rooftops. However, the panel rejected Hunter’s comment and retained the values in the table. Fred durso, Jr. is staff writer for NFPA Journal. MAY/JUNE 2013 NFPA JOURNAL 63

Table of Contents for the Digital Edition of NFPA Journal - May/June 2013

NFPA Journal - May/June 2013
Contents
First Word
In a Flash
Perspectives
Firewatch
Research
Heads Up
Structural Ops
In Compliance
Buzzwords
Outreach
Electrical Safety
Wildfire Watch
Treasurer's Report
Work in Progress
Amping It Up
Drill Team
Working Together
Code Process 2.0
Routine Maintenance
Here, There, Everywhere
Section Spotlight
Expo Preview: Exhibitors' Showcase
Looking Back

NFPA Journal - May/June 2013