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

Choice of circuit-breaker for LED lamps and fixtures

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

Fig. N46 – Coordination between circuit breaker and luminaires LED

• 

  [a] Rating 10 A

• 

  [b] Rating 16 A

• 

  [c] Rating 20 A

• 

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+
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

Fig. N47 – Maximum number of lamps according to the circuit breaker rating and curve, for LED lamps

Depending on the control device used, the transient current surge may:

• require derating of the circuit breaker according to the coordination curves between the number of luminaires and the circuit breaker rating, when using conventional control devices: CT, TL (electromechanical control device),
• be reduced by using the following technologies:
  • softStart: implemented by a control integrated in the driver or by the dimmer,
  • controlled-action control contactor (iTL+, iCT+) (closing on zero crossing by the voltage, only derating is linked to the lighting circuit's power factor.

These technologies make it possible to use the circuit breakers without derating due to the lamp technology.

Example:

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

Other lamp technologies

The Figure N55 below indicates the maximum number of lamps according to the circuit breaker rating and curve , for C-curve circuit breakers

• for B-curve circuit breakers, the number of lamps should be reduced by 50%,
• for D-curve circuit breakers, the number of lamps should be increased by 50%.

Products			Circuit breaker (C curve)
Type of lamp			10 A	16 A	25 A	40 A	63 A
Standard incandescent lamps, LV halogen lamps, replacement mercury vapor lamps (without ballast)
	40 W		28	46	70	140	207
	60 W		23	36	55	103	152
	75 W		29	31	46	80	121
	100 W		15	23	33	60	88
ELV 12 or 24 V halogen lamps
Ferromagnetic transformer	20 W		11	19	27	50	75
	50 W		8	12	19	33	51
	75 W		7	10	14	27	43
	100 W		5	8	10	22	33
Electronic transformer	20 W		47	74	108	220	333
	50 W		19	31	47	92	137
	75 W		15	24	34	64	94
	100 W		12	20	26	51	73
Fluorescent tubes with starter and ferromagnetic ballast
1 tube without compensation	15 W		16	26	37	85	121
	18 W		16	26	37	85	121
	20 W		16	26	37	85	121
	36 W		15	24	34	72	108
	40 W		15	24	34	72	108
	58 W		9	15	21	43	68
	65 W		9	15	21	43	68
	80 W		8	12	19	36	58
	115 W		6	9	12	24	38
1 tube with parallel compensation	15 W	5 µF	11	19	24	48	72
	18 W	5 µF	11	19	24	48	72
	20 W	5 µF	11	19	24	48	72
	36 W	5 µF	11	19	24	48	72
	40 W	5 µF	11	19	24	48	72
	58 W	7 µF	8	12	19	36	51
	65 W	7 µF	8	12	19	36	51
	80 W	7 µF	8	12	19	36	51
	115 W	16 µF	4	7	9	17	24
2 or 4 tubes with series compensation	2 x 18 W		23	36	56	96	148
	4 x 18 W		12	20	29	52	82
	2 x 36 W		12	20	29	52	82
	2 x 58 W		8	12	20	33	51
	2 x 65 W		8	12	20	33	51
	2 x 80 W		7	11	15	26	41
	2 x 115 W		5	8	12	20	31
Fluorescent tubes with electronic ballast
1 or 2 tubes	18 W		56	90	134	268	402
	36 W		28	46	70	142	213
	58 W		19	31	45	90	134
	2 x 18 W		27	44	67	134	201
	2 x 36 W		16	24	37	72	108
	2 x 58 W		9	15	23	46	70
Compact fluorescent lamps
External electronic ballast	5 W		158	251	399	810	Infrequent use
	7 W		113	181	268	578
	9 W		92	147	234	463
	11 W		79	125	196	396
	18 W		49	80	127	261
	26 W		37	60	92	181
Integral electronic ballast (replacing incandescent lamps)	5 W		121	193	278	568	859
	7 W		85	137	198	405	621
	9 W		71	113	160	322	497
	11 W		59	94	132	268	411
	18 W		36	58	83	167	257
	26 W		25	40	60	121	182
Low-pressure sodium vapor lamps with ferromagnetic ballast and external ignitor
Without compensation	35 W		4	7	11	17	29
	55 W		4	7	11	17	29
	90 W		3	4	8	11	23
	135 W		2	3	5	8	12
	180 W		1	2	4	7	10
With parallel compensation	35 W	20 µF	3	4	7	12	19
	55 W	20 µF	3	4	7	12	19
	90 W	26 µF	2	3	5	8	13
	135 W	40 µF	1	2	3	5	9
	180 W	45 µF	0	1	2	4	8
High-pressure sodium vapor lamps Metal-iodide lamps
Ferromagnetic ballast with external ignitor, without compensation	35 W		12	19	28	50	77
	70 W		7	11	15	24	38
	150 W		3	5	9	15	22
	250 W		2	3	5	10	13
	400 W		0	1	3	6	10
	1000 W		0	0	1	2	3
Ferromagnetic ballast and external ignitor, with parallel compensation	35 W	6 µF	14	17	26	43	70
	70 W	12 µF	8	9	13	23	35
	150 W	20 µF	5	6	9	14	21
	250 W	32 µF	3	4	5	10	14
	400 W	45 µF	2	3	4	7	9
	1000 W	60 µF	0	1	2	4	7
	2000 W	85 µF	0	0	1	2	3
Electronic ballast	35 W		15	24	38	82	123
	70 W		11	18	29	61	92
	150 W		6	9	14	31	48

[a]  Circuits with non-compensated ferromagnetic ballasts consume twice as much current for a given power output. This explains the small number of lamps in this configuration.
[b]  The total capacitance of the power factor capacitors in parallel on a circuit limits the number of lamps that can be controlled by a contactor. The total downstream capacitance of a modular contactor of rating 16, 25, 40 or 63 A should not exceed 75, 100, 200 or 300 μF respectively. Allow for these limits to calculate the maximum acceptable number of lamps if the capacitance values are different from those in the table.
High-pressure sodium vapor lamps: for the 10 A and 16 A B-curve ratings, the number of lamps should be reduced by 10% to limit unwanted magnetic tripping.

Fig. N55 – Maximum number of lamps according to the circuit breaker rating and curve, for other technologies than LED