Chapter N

Characteristics of particular sources and loads


LED lamps - choice of circuit breaker

From Electrical Installation Guide

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

Fig. N48 – Maximum number of lamps according to the circuit breaker rating and curve, for LED lamps
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+
10 15 30 48 - 22 44 69 - 32 63 98 -
30 11 24 38 57 17 34 54 90 25 49 77 110
50 8 17 27 41 12 25 39 66 18 35 56 83
75 4 11 17 28 7 15 25 44 11 21 36 55
150 - 5 9 13 2 7 12 22 4 9 18 28
250 - 3 5 8 - 4 7 13 - 5 10 16
400 - 1 4 5 - 2 6 8 - 3 9 10

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.

Example:

Circuit rated power = 230 V AC x Circuit breaker rating x Cos φ.

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