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IAEI Magazine | Author: Travis C. Lindsey
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Travis C. Lindsey

Travis C. Lindsey, Travis Lindsey Consulting Services, Inc., Las Vegas, Nevada, retired in 2001 with 27 years public service with Clark County, Nevada, where he held positions of electrical inspector, electrical plans examiner and assistant manager of the plan review division. He served as the founding president of the Southern Nevada chapter of the International Association of Electrical Inspectors (IAEI). Lindsey has been known for work on the IAEI SNC Grounding study, the national Electrical Grounding Research Project and most recently Copper Development Associations ambient temperature research. Travis is a master electrician and is certified as electrical inspector and plans examiner under ICC and ICBO.


Energy Loss, Global Warming and Voltage Drop

Safety first. That’s been the byword for electrical codes and electrical inspectors forever — and properly so. But is that enough? For people and property, the answer is "Yes.” But for economic and enviornmental reasons, the answer is: "Maybe we should be doing more.”

Effect of Rooftop Exposure on Ambient Temperatures Inside Conduits

New requirements for ampacity correction factors for conductors installed in conduits on rooftops were introduced in the 2008 NEC at Section 310.15(B)(2)(c). This new requirement for ampacity correction due to ambient temperature resulted from extensive study and fact-finding efforts that collected data which demonstrated valid concerns about excessive heat exposure for conductors and cables installed on rooftops exposed to sunlight. These studies clearly warranted new requirements for ampacity correction factors for such installations.

Effect of Rooftop Exposure on Ambient Temperatures Inside Conduits

The interiors of conduits in sunlight, such as those containing conductors feeding air conditioning units on rooftops, become significantly hotter than the outside air (which is always measured in the shade). Data show that these temperature differentials can easily reach 70°F, even when the conductors are electrically unloaded. Remarkably, the differentials were found to be essentially independent of the outdoor temperature all through the range from 70°F to above 100°F.

Ambient Temperature Ampacity Corrections for Cable Bundling and Direct Solar Exposure

Heat is one of the enemies of electrical systems. As part of a larger study of elevated ambient temperatures in residential and non-residential structures in Las Vegas, Nevada, two experiments were carried out that would seem to require some action in the National Electrical Code. They involve 1) bundled cable normally found above a load center or at other points of concentrated electrical service, and 2) conductors in conduits exposed to direct sunlight.