Age and the incidence of fires in electrical installations

The paper reviews data on the occurrence of fires due to defects in fixed electrical installations amongst a population of about 2.5 million consumers over the years 1951¿53 inclusive. The correlation between age of installation and the incidence of fires is examined, and it is shown that for installations more than fifteen years old the incidence of fires is roughly proportional to the age of installation. There is no clear indication of any maximum safe life. Installations less than 15 years old are considered as a separate class, being subject to innovations in housing construction and installation practice. Incomplete data on the types of equipment revealed as defective and on the nature of the defects are reviewed. There is no clear indication that any one type of equipment is particularly subject to the effects of age. The most frequent primary cause of fire is defective wiring, and the most frequent secondary cause fortuitous contact between wiring or earth-continuity conductors and composition gas-pipes. Apart from the latter, there seems no single type of defect the elimination of which could lead to outstanding reduction in the incidence of fires.