Field measurement of branch circuit wire temperatures
Abstract
Temperature excursions of residential branch circuit wiring under field conditions were monitored to develop a field data base needed to determine the prevailing conditions in the field and to respond to various assertions that the encapsulation of branch circuit wiring within thermal insulation is a potential hazard. Previous laboratory investigations demonstrated that buried wires, when operated continuously at rated ampacity, will exceed the thermal limit established by the National Electrical Code (NEC). Approximately 2,800 circuits in 667 residences were monitored through a volunteer program with the utilities. The results show that slightly more than one-third of the circuits monitored operated at or above the thermal limit established by the NEC, 60 C (140 F). Thermal distributions are shown for variables such as: region, season, and age.
- Publication:
-
NASA STI/Recon Technical Report N
- Pub Date:
- October 1981
- Bibcode:
- 1981STIN...8229502F
- Keywords:
-
- Circuit Protection;
- Electric Wire;
- Temperature Measurement;
- Thermal Insulation;
- Encapsulating;
- Hazards;
- Residential Energy;
- Resistance Heating;
- Temperature Distribution;
- Engineering (General)