Heat Losses in Isolated-Phase Bus Enclosures

Formulas are given for the evaluation of heat losses in the enclosures of isolated-phase bus installations in flat configuration. Middle-and outside-phase losses in open-circuited and electrically bonded enclosures are considered. Middle-phase open-circuited enclosure losses estimated by the proposed formula are compared with loss values inferred from temperature data on 40 heat runs involving a wide range of design parameters. The comparison shows acceptable agreement.