Industrial & Commercial
- Connectability Testing of Copper and Aluminum Wiring [Full Report PDF ~ 3.3Mb]
A report by Powertech Labs of research they recently conducted into wiring systems showed a very high (up to 100%) failure rate for aluminum systems in mechanical connectors, irrespective of conductor preparation, conductive greases or torque levels when tested according to an IEC method. Copper conductors in copper connectors passed in every case. - Copper or Aluminum: Connectability Counts [PDF ~ 616Kb]
A short article explaining the Powertech study of copper and aluminum wiring systems, and summarizing the results. In this study of connectability, copper systems clearly outperformed alternates. - Recommended Practices for Designing and Installing Copper Building Wire System [PDF ~ 10Mb]
Copper wire systems are the most widely used of all electrical systems and are often found whenever reliability and connectability are important. This document covers the installation and maintenance of copper building wire permanently installed in building premises wiring systems for multiple applications. The reference materials are based on the 2011 edition of the National Electrical Code®. - PART 2: UL Fact Finding Report on Ambient Temperature Adjustments for Raceway and Cable Systems Exposed to Sunlight on Rooftops at Higher Elevations [PDF - 655Kb]
A supplement Fact Finding Report (below) was prepared of measurements at higher elevations above rooftops. This report details the findings at 3 and 5 feet above rooftops. (UL Project 12CA25371). Reprinted with permission. - PART 1: UL Fact Finding Report on Ambient Temperature Adjustments for Raceway and Cable Systems Exposed to Sunlight on Rooftops [PDF - 5.5Mb]
Full report of the UL fact finding, representing every wiring method allowed on rooftops, and the effect of height above the rooftop. Supplements and expands the study by Travis Lindsey Consulting Services, detailed below, on the same subject. Reprinted with permission. - Outdoor and Rooftop Temperatures for Selected U.S. and Canadian Locations
The National Electrical Code requires that electrical cables be used at temperatures below the listed ratings of the insulation material, or they may be damaged. Ambient temperature is understood to mean the temperature of the air surrounding the conductor. The data presented provides the peak and 2% design temperatures for various cities, as well as the elevated ambient temperature inside rooftop raceway exposed to direct sunlight. - Effect of Rooftop Exposure in Direct Sunlight on Conduit Ambient Temperatures [PDF - 212Kb]
An IEEE paper on 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). Temperature differentials need to be added to the outdoor temperatures to determine ampacity. IEEE Transactions on Industry Applications, Vol. 44, No. 6, November/December 2008. - Guide to Specialty Cables [PDF - 439 KB]
Specialty cables include those types used where hazardous locations or materials are found or special properties such as fire resistance are needed. This basic article describes the various types of such cables, where they might be used, and their basic construction - AS SEEN IN NEC DIGEST
Corrosion and Current Burst Testing of Copper and Aluminum Power Connectors for Use with Copper and Aluminum Conductor [PDF - 2Mb]
Crimped and mechanically bolted aluminum and copper connectors are commonly used for terminating electric power cables. In this study, copper-to-copper, aluminum-to-copper, and aluminum-to-aluminum connections were subjected to accelerated aging. The all-copper connections performed best. This is the full report. - Bigger Really Is Better
"Inspectors and Contractors Prefer Larger Gages and More Circuits" A recent survey of electrical inspectors, contractors and instructors indicated an overwhelming preference for more circuits, larger gages than Code minimums, and copper conductors in their own homes. - Connecting With Copper Is Connecting With Trust [PDF - 1.7Mb]
Colorful, six page summary of the results of the aluminum and copper connector study detailed below, with photographs and a description of the research and results. - Comparative Corrosion and Current Burst Testing of Copper and Aluminum Electrical Power Connectors [PDF - 1.41Mb]
This IEEE Paper, presented at the 2005 Industry Applications Conference, reports on testing of aluminum and copper power connectors. The performance of copper and aluminum connectors was compared by conducting accelerated aging tests. The connectors were evaluated by comparing the change in resistance of the test samples as the test progressed. The results of these tests point to a high level of failure of the aluminum connectors.
(The full report of the study by Powertech Labs can be ordered from the Publication List) - Copper Building Wire Systems
An overview of copper building wire-covers installation, corrosion, codes, strength, and more. - Copper-The Best Buy in Building Wire
Ten reasons why contractors prefer to use copper in wiring systems. - More Information can be found in our Power Quality section.
- Do you Have a "Wiring for Power Quality" Story?
CDA is interested in how your company enhanced productivity or alleviated power quality problems through robust wiring.
For Contractors & Inspectors
- Temperature Adjustment for Rooftop Conductors
Underwriters Laboratories (UL) examined every possible rooftop wiring method to determine conductor temperatures as a result of exposure to direct sunlight at various heights above the roof. This DVD describes the methodology and findings of the experiments. The results can be used in determining ampacity corrections required to meet the National Electrical Code®. - The Elevated Ambient Temperature Experiment
These videos explain the background, methodology and results of the rooftop solar exposure experiments conducted over the past several years.
Overview - Elevated Ambient Temperature Study - Conductor "Bundling" Experiments
These video segments explore what happens when current-carrying conductors are run together in wall cavities, with and without thermal insulation. Overview - Conductor Groupings With & Without Thermal Insulation Experiment Details - Conductor Groupings with & Without Thermal Insulation - Ambient Temperature Ampacity Corrections for Cable Bundling and Direct Solar Exposure [PDF - 727Kb]
- Temperatures of Bundled Electrical Cables Installed in Bored Holes in Residential Wood Framing [PDF - 319Kb]
For Consumers
- Home Charging Stations Are a Real Gas (Saver)
Several new GPS manufacturers can now steer you to the nearest electric vehicle charging station while you're on the road; but, you probably don't need a GPS to show you how to "Go Home." Your home is the most convenient (and probably the cheapest place) for you to fill up your all-electric or plug-in electric hybrid vehicle (PEV). - "Aged Wiring Can Be A Hazard"
Hazards of older wiring and a report issued by the Fire Protection Research Foundation. Any home 25 years or older should be considered for inspection by a qualified electrical contractor. - Do You Need an Electrician?
- Home Planning Section
- Electrical Safety Foundation International Warns Consumers About the Dangers of Counterfeit Electrical Products