LED lamps - choice of circuit breaker
For LED lamps, the device which limits the number of luminaires is the MCB and not the contactor like for other lamp technologies
The new lighting technologies with electronic interfaces (ballasts, drivers) cause a large transient inrush current at power up which could result in circuit breaker tripping.
These phenomena are especially significant with LED lighting.
Coordination curves between the number of LED luminaires and circuit breaker rating
Maximum number of LED luminaires depending on the circuit breaker rating and curve
|Unit power of the luminaire (W)||Circuit breaker rating and curve|
|10 A||16 A||20 A|
|B||C||D||B, C, D with iCT+ or iTL+||B||C||D||B, C, D with iCT+ or iTL+||B||C||D||B, C, D with iCT+|
According to the control device used, the transient current surge may:
- require the circuit breaker to be derated according to the number of luminaires / circuit breaker rating coordination curves, when using standard control devices: CT, TL (electromechanical control device),
- be reduced by the use of the following technologies:
- softStart: using a command integrated in the driver or a dimmer switch,
- controlled contactor (iTL+, iCT+) (closes when the voltage passes through «0», derating is related to the Cos φ of the lighting circuit).
These technologies allow circuit breakers without derating related to the technology of the lamps to be used.
Circuit rated power = 230 V AC x Circuit breaker rating x Cos φ.