Circuit breaker, electromagnetic response

In large luminaire groups, the inrush current can cause a circuit breaker (CB) located in the electrical installation to switch off occasionally due to its magnetic trip – which is intended as a safety feature to quickly switch off the mains voltage in case of short-circuits – depending on the actually occurring inrush current due to phasing at the moment of switching on.

To avoid tripping the CB, manufacturers provide information on the permissible number of control gear units for connection to CB of varying current capacity and magnetic trip specification in their LED control gear product data sheets (see figure). Furthermore, they specify the inrush current values for their products. In general, C devices are recommended for lighting groups.

The referenced inrush currents are reached if the control gear unit is operated at the voltage source with the circuit breaker in question and there are no further current-limiting components (e.g. long lines) incorporated in the installation. In practice, it is therefore possible for the circuit breakers to fail to release even if the number of control gear units specified in the data sheet is exceeded.