Moulded case circuit breaker: A product study; Larsen and Toubro, Bombay

Abstract

Moulded Case Circuit Breakers are designed to provide protection to low voltage distribution system. L & T was the first company to bring MCCB technology to India. MCCB is being increasingly accepted in Indian industry as a circuit protection device. | & T offers family of circuit breakers in various frame sizes which cater to varied applications. The study was undertaken to understand various aspects related to this product like major users, typical applications, important attributes & typical problems faced in use of this product. The total market for MCCB was divided into 4 categories Consultants, Panel Builders, OEMs & End Users. The sample size of around 20 was decided in each category. A questionnaire was administered to each category & also personal interview session was held. Separate response cards were used during the interview to judge the performance of L & T vis-a-vis other companies. Among the players in this product segment, Crompton Greaves has market share of around 45 % followed by L & T with 25 &. The use of MCCB as % of total switching operation is found to be low. MCCB is used mainly for motor load & distribution toad. Technical reasons ( like breaking capacity, adjustable thermal setting) is the most important criterion while selecting MCCB. Ease of installation is also important. Compact design of MCCB is not perceived as important product attribute. End users still use fuses as protection along with MCCB. Compared with conventional switch-fuse unit, MCCB is lower in size & weight. Also operating cost for MCCB is lower. Nuisance tripping is a major problem with MCCB. It is also not found suitable in motor starting operation. Termination of cable is also a problem.