- Author
-
Meese, W. J.
|
Beausoliel, R. W.
- Title
- Exploratory Study of Glowing Electrical Connections. Final Report.
- Coporate
- National Bureau of Standards, Gaithersburg, MD
- Sponsor
- Department of Housing and Urban Development, Washington, DC
- Report
-
NBSIR 76-1011,
November 1976,
27 p.
- Distribution
- Available from National Technical Information Service
- Keywords
-
fire hazards
- Abstract
- [NBS BSS 103 supersedes this report] This report describes and characterizes with quantifiable electrical and thermal measures the extent to which loose electrical connections in residential-type brance circuits have overheated in the laboratory. With loose electrical connections, which conceivably could be inadvertently duplicated in field installations, but with otherwise normal installation and operating conditions, visible glows have been observed under laboratory test conditions in nominal 120-volt, 15 and 20 ampere branch circuits with both copper and aluminum wire. Characteristics of the glow condition are differentiated from arcing/sparking as sometimes observed in making or breaking electrical circuits. Glowing electrical connections may dissipate as much as 35 watts of power with a current of 15 amps in the circuit and as much as 5 watts with a current of 0.8 amp in the circuit. Temperatures over 750 deg.F were measured on the "break-off tab" of receptacles. Metal outlet boxes housing glowing connections in an insulated wall test set-up representative of a common type of residential construction attained temperatures in excess of 450 deg F. In laboratory tests under repetitive, intermittent and periodic cycles, a glow conditions maintained for over 100 hours. Glowing connections will not perceptibly affect the electrical performance function of lights, appliances or other electrical loads, and will not "blow" fuses, trip circui breakers or operate ground fault circuit interrupters.