Other lamp technologies - constraints and recommendations

The current actually drawn by luminaires

The risk
This characteristic is the first one that should be defined when creating an installation, otherwise it is highly probable that overload protection devices will trip and users may often find themselves in the dark.
It is evident that their determination should take into account the consumption of all components, especially for fluorescent lighting installations, since the power consumed by the ballasts has to be added to that of the tubes and bulbs.

The solution
For incandescent lighting, it should be remembered that the line voltage can be more than 10% of its nominal value, which would then cause an increase in the current drawn.
For fluorescent lighting, unless otherwise specified, the power of the magnetic ballasts can be assessed at 25% of that of the bulbs. For electronic ballasts, this power is lower, in the order of 5 to 10%.
The thresholds for the overcurrent protection devices should therefore be calculated as a function of the total power and the power factor, calculated for each circuit.

Overcurrents at switch-on

The risk
The devices used for control and protection of lighting circuits are those such as relays, triac, remote-control switches, contactors or circuit-breakers.
The main constraint applied to these devices is the current peak on energization.
This current peak depends on the technology of the lamps used, but also on the installation characteristics (supply transformer power, length of cables, number of lamps) and the moment of energization in the line voltage period. A high current peak, however fleeting, can cause the contacts on an electromechanical control device to weld together or the destruction of a solid state device with semi-conductors.

Two solutions
Because of the inrush current, the majority of ordinary relays are incompatible with lighting device power supply. The following recommendations are therefore usually made:

• Limit the number of lamps to be connected to a single device so that their total power is less than the maximum permissible power for the device
• Check with the manufacturers what operating limits they suggest for the devices. This precaution is particularly important when replacing incandescent lamps with compact fluorescent lamps

By way of example, the table in Figure N49 indicates the maximum number of compensated fluorescent tubes that can be controlled by different devices with 16 A rating. Note that the number of controlled tubes is well below the number corresponding to the maximum power for the devices.

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Tube unit power   requirement  (W)	Number of tubes corresponding to the power 16 A x 230 V	Maximum number of tubes that can be controlled by
		Contactors GC16 A CT16 A	Remote control switches TL16 A	'Circuit- breakers C60-16 'A
18	204	15	50	112
36	102	15	25	56
58	63	10	16	34

Fig. N49: The number of controlled tubes is well below the number corresponding to the maximum power for the devices

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But a technique exists to limit the current peak on energization of circuits with capacitive behavior (magnetic ballasts with parallel compensation and electronic ballasts). It consists of ensuring that activation occurs at the moment when the line voltage passes through zero. Only solid state switches with semi-conductors offer this possibility (see Fig. N50a). This technique has proved to be particularly useful when designing new lighting circuits.
More recently, hybrid technology devices have been developed that combine a solid state switch (activation on voltage passage through zero) and an electromechanical contactor short-circuiting the solid state switch (reduction of losses in the semi-conductors) (see Fig. N50b).

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a                   b                   c

Fig. N50: “Standard” CT+ contactor [a], CT+ contactor with manual override, pushbutton for selection of operating mode and indicator lamp showing the active operating mode [b], and TL + remote-control switch [c] (Merlin Gerin brand)

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Choice of relay rating according to lamp type

Modular contactors and impulse relays do not use the same technologies. Their rating is determined according to different standards. For example, for a given rating, an impulse relay is more efficient than a modular contactor for the control of light fittings with a strong inrush current, or with a low power factor (non-compensated inductive circuit).

Figure 51 shows the maximum number of light fittings for each relay, according to the type, power and configuration of a given lamp. As an indication, the total acceptable power is also mentioned.

• These values are given for a 230 V circuit with 2 active conductors (single-phase phase/neutral or two-phase phase/phase). For 110 V circuits, divide the values in the table by 2.
• To obtain the equivalent values for the whole of a 230 V three-phase circuit, multiply the number of lamps and the total acceptable power:

  -  by [math]\displaystyle{ \sqrt 3 }[/math] (1.73) for circuits without neutral;
  -  by 3 for circuits with neutral.
Note: The power ratings of the lamps most commonly used are shown in bold.

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Type of lamp	Unit power and capacitance of power factor correction capacitor		Maximum number of light fittings for a single-phase circuit and maximum power output per circuit
			TL impulse relay				CT contactor
			16A		32A		16A		25A		40A		63A
Basic incandescent lamps LV halogen lamps Replacement mercury vapour lamps (without ballast)
	40W		40	1500 W to 1600 W	106	4000 W to 4200 W	38	1550 W to 2000 W	57	2300 W to 2850 W	115	4600 W to 5250 W	172	6900 W to 7500 W
	60W		25		66		30		45		85		125
	75W		20		53		25		38		70		100
	100W		16		42		19		28		50		73
	150W		10		28		12		18		35		50
	200W		8		21		10		14		26		37
	300W		5	1500 W	13	4000 W	7	2100 W	10	3000 W	18	5500 W to 6000 W	25	7500 W to 8000 W
	500W		3		8		4		6		10		15
	1000W		1		4		2		3		6		8
	1500W		1		2		1		2		4		5
ELV 12 or 24 V halogen lamps
With ferromagnetic transformer	20W		70	1350 W to 1450 W	180	3600 W to 3750 W	15	300 W to 600 W	23	450 W to 900 W	42	850 W to 1950 W	63	1250 W to 2850 W
	50W		28		74		10		15		27		42
	75W		19		50		8		12		23		35
	100W		14		37		6		8		18		27
With electronic transformer	20W		60	1200 W to 1400 W	160	3200 W to 3350 W	62	1250 W to 1600 W	90	1850 W to 2250 W	182	3650 W to 4200 W	275	5500 W to 6000 W
	50W		25		65		25		39		76		114
	75W		18		44		20		28		53		78
	100W		14		33		16		22		42		60
Fluorescent tubes with starter and ferromagnetic ballast
1 tube without compensation (1)	15W		83	1250 W to 1300 W	213	3200 W to 3350 W	22	330 W to 850 W	30	450 W to 1200 W	70	1050 W to 2400 W	100	1500 W to 3850 W
	18W		70		186		22		30		70		100
	20W		62		160		22		30		70		100
	36W		35		93		20		28		60		90
	40W		31		81		20		28		60		90
	58W		21		55		13		17		35		56
	65W		20		50		13		17		35		56
	80W		16		41		10		15		30		48
	115W		11		29		7		10		20		32
1 tube with parallel compensation (2)	15W	5 µF	60	900 W	160	2400 W	15	200 W to 800 W	20	300 W to 1200 W	40	600 W to 2400 W	60	900 W to 3500 W
	18W	5 µF	50		133		15		20		40		60
	20W	5 µF	45		120		15		20		40		60
	36W	5 µF	25		66		15		20		40		60
	40W	5 µF	22		60		15		20		40		60
	58W	7 µF	16		42		10		15		30		43
	65W	7 µF	13		37		10		15		30		43
	80W	7 µF	11		30		10		15		30		43
	115W	16µF	7		20		5		7		14		20
2 or 4 tubes with series compensation	2 x 18W		56	2000 W	148	5300 W	30	1100 W to 1500 W	46	1650 W to 2400 W	80	2900 W to 3800 W	123	4450 W to 5900 W
	4 x 18W		28		74		16		24		44		68
	2 x 36 W		28		74		16		24		44		68
	2 x 58 W		17		45		10		16		27		42
	2 x 65 W		15		40		10		16		27		42
	2 x 80 W		12		33		9		13		22		34
	2 x 115 W		8		23		6		10		16		25
Fluorescent tubes with electronic ballast
1 or 2 tubes	18W		80	1450 W to 1550 W	212	3800 W to 4000 W	74	1300 W to 1400 W	111	2000 W to 2200 W	222	4000 W to 4400 W	333	6000 W to 6600 W
	36W		40		106		38		58		117		176
	58W		26		69		25		37		74		111
	2 x18 W		40		106		36		55		111		166
	2 x36 W		20		53		20		30		60		90
	2 x 58 W		13		34		12		19		38		57
Compact fluorescent lamps
With external electronic ballast	5 W		240	1200  W to 1450 W	630	3150 W to 3800 W	210	1050 W    to 1300 W	330	1650 W     to 2000 W	670	3350 W to 4000 W	not tested
	7 W		171		457		150		222		478
	9 W		138		366		122		194		383
	11 W		180		318		104		163		327
	18 W		77		202		66		105		216
	26 W		55		146		50		76		153
With integral electronic ballast (replacement for incandescent lamps)	5 W		170	850 W to 1050 W	390	1950 W to 2400 W	160	800 W to 900 W	230	1150 W to 1300 W	470	2350 W to 2600 W	710	3550 W to 3950 W
	7 W		121		285		114		164		335		514
	9 W		100		233		94		133		266		411
	11 W		86		200		78		109		222		340
	18 W		55		127		48		69		138		213
	26 W		40		92		34		50		100		151
High-pressure mercury vapour lamps with ferromagnetic ballast without ignitor Replacement high-pressure sodium vapour lamps with ferromagnetic ballast with integral ignitor (3)
Without compensation (1)	50 W		not tested, infrequent use				15	750 W to 1000 W	20	1000 W to 1600 W	34	1700 W to 2800 W	53	2650 W to 4200 W
	80 W						10		15		27		40
	125/110W						8		10		20		28
	250 / 220 W (3)						4		6		10		15
	400 / 350 W (3)						2		4		6		10
	700 W						1		2		4		6
With parallel compensation (2)	50 W	7 µF					10	500 W to 1400 W	15	750 W to 1600 W	28	1400 W to 3500 W	43	2150 W to 5000 W
	80 W	8 µF					9		13		25		38
	125/ 110W	10 µF					9		10		20		30
	250 /  220  W (3)	18 µF					4		6		11		17
	400 / 350 W (3)	25 µF					3		4		8		12
	700 W	40 µF					2		2		5		7
	1000 W	60 µF					0		1		3		5
Low-pressure sodium vapour lamps with ferromagnetic ballast with external ignitor
Without compensation (1)	35 W		not tested, infrequent use				5	270 W to 360 W	9	320 W to 720 W	14	500 W to 1100 W	24	850 W to 1800 W
	55 W						5		9		14		24
	90 W						3		6		9		19
	135 W						2		4		6		10
	180 W						2		4		6		10
With parallel compensation (2)	35 W	20 µF	38	1350 W	102	3600 W	3	100 W to 180 W	5	175 W to 360 W	10	350 W to 720 W	15	550 W to 1100 W
	55 W	20 µF	24		63		3		5		10		15
	90 W	26 µF	15		40		2		4		8		11
	135 W	40 µF	10		26		1		2		5		7
	180 W	45 µF	7		18		1		2		4		6
High-pressure sodium vapour lamps Metal-iodide lamps
With ferromagnetic ballast with external ignitor, without compensation (1)	35 W		not tested, infrequent use				16	600 W	24	850 W to 1200 W	42	1450 W to 2000 W	64	2250 W to 3200 W
	70 W						8		12		20		32
	150 W						4		7		13		18
	250 W						2		4		8		11
	400 W						1		3		5		8
	1000 W						0		1		2		3
With ferromagnetic ballast with external ignitor and parallel compensation (2)	35 W	6 µF	34	1200 W to 1350 W	88	3100 W to 3400 W	12	450 W to 1000 W	18	650 W to 2000 W	31	1100 W to 4000 W	50	1750 W to 6000 W
	70 W	12 µF	17		45		6		9		16		25
	150 W	20 µF	8		22		4		6		10		15
	250 W	32 µF	5		13		3		4		7		10
	400 W	45 µF	3		8		2		3		5		7
	1000 W	60 µF	1		3		1		2		3		5
	2000 W	85 µF	0		1		0		1		2		3
With electronic ballast	35 W		38	1350 W to 2200 W	87	3100 W to 5000 W	24	850 W to 1350 W	38	1350 W to 2200 W	68	2400 W to 4000 W	102	3600 W to 6000 W
	70 W		29		77		18		29		51		76
	150 W		14		33		9		14		26		40

(1) Circuits with non-compensated ferromagnetic ballasts consume twice as much current for a given lamp power output. This explains
      the small number of lamps in this configuration.
(2) The total capacitance of the power factor correction capacitors in parallel in 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.
(3) High-pressure mercury vapour lamps without ignitor, of power 125, 250 and 400 W, are gradually being replaced by high-pressure
    sodium vapour lamps with integral ignitor, and respective power of 110, 220 and 350 W.

Fig. N51: Maximum number of light fittings for each relay, according to the type, power and configuration of a given lamp (Concluded)

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Protection of lamp circuits: Maximum number of lamps and MCB rating versus lamp type, unit power and MCB tripping curve
During start up of discharge lamps (with their ballast), the inrush current drawn by each lamp may be in the order of:

• 25 x circuit start current for the first 3 ms
• 7 x circuit start current for the following 2 s

For fluorescent lamps with High Frequency Electronic control ballast, the protective device ratings must cope with 25 x inrush for 250 to 350 µs.
However due to the circuit resistance the total inrush current seen by the MCB is lower than the summation of all individual lamp inrush current if directly connected to the MCB.
The tables below (see Fig. N52 to NXX) take into account:

• Circuits cables have a length of 20 meters from distribution board to the first lamp and 7 meters between each additional fittings.
• MCB rating is given to protect the lamp circuit in accordance with the cable cross section, and without unwanted tripping upon lamp starting.
• MCB tripping curve (C = instantaneous trip setting 5 to 10 In, D = instantaneous trip setting 10 to 14 In).

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Lamp power (W)	Number of lamps per circuit
	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20
MCB rating C & D tripping curve
14/18	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
14x2	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
14x3	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	10	10	10
14x4	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	10	10	10	10
18x2	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
18x4	6	6	6	6	6	6	6	6	6	6	6	6	6	10	10	10	10	10	10	10
21/24	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
21/24 x 2	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
28	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
28x2	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	10	10	10
35/36/39	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
35/36 x 2	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	10	10	10	10	10
38/39 x 2	6	6	6	6	6	6	6	6	6	6	6	6	10	10	10	10	10	10	10	10
40/42	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
40/42 x2	6	6	6	6	6	6	6	6	6	6	6	10	10	10	10	10	10	10	10	16
49/50	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
49/50 x2	6	6	6	6	6	6	6	6	6	6	10	10	10	10	10	10	16	16	16	16
54/55	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	10	10
54/55 x2	6	6	6	6	6	6	6	6	10	10	10	10	10	10	16	16	16	16	16	16
60	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	10	10	10	10

Fig. N52: Fluorescent tubes with electronic ballast - Vac = 230 V

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Lamp power (W)	Number of lamps per circuit
	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20
MCB rating C & D tripping curve
6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
9	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
11	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
13	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
14	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
15	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
16	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
17	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
18	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
20	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
21	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
23	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
25	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	10

Fig. N53: Compact fluorescent lamps - Vac = 230 V

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Lamp power (W)	Number of lamps per circuit
	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20
MCB rating C tripping curve
50	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	10	10	10	10
80	6	6	6	6	6	6	6	6	6	6	10	10	10	10	10	10	10	16	16	16
125	6	6	6	10	10	10	10	10	10	10	10	16	16	16	16	16	16	16	20	20
250	6	10	10	16	16	16	16	16	16	20	20	25	25	25	32	32	32	32	40	40
400	6	16	20	25	25	32	32	32	32	32	32	40	40	40	50	50	50	50	63	63
1000	16	32	40	50	50	50	50	50	63	-	-	-	-	-	-	-	-	-	-	-
MCB rating D tripping curve
50	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	10	10	10	10
80	6	6	6	6	6	6	6	6	6	6	10	10	10	10	10	10	16	16	16	16
125	6	6	6	6	6	6	10	10	10	10	10	16	16	16	16	16	16	16	20	20
250	6	6	10	10	10	10	16	16	16	20	20	25	25	25	32	32	32	32	40	40
400	6	10	16	16	20	20	25	25	25	32	32	40	40	40	50	50	50	50	63	63
1000	10	20	25	32	40	40	50	63	63	-	-	-	-	-	-	-	-	-	-	-

Fig. N54: High pressure mercury vapour (with ferromagnetic ballast and PF correction) - Vac = 230 V

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Lamp power (W)	Number of lamps per circuit
	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20
MCB rating C tripping curve
Ferromagnetic ballast
18	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
26	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
35/36	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
55	6	6	6	6	6	6	6	6	6	6	6	6	6	10	10	10	10	10	10	10
91	6	6	6	6	6	6	6	6	6	10	10	10	10	10	10	10	16	16	16	16
131	6	6	6	10	10	10	10	10	10	10	10	10	16	16	16	16	16	16	16	20
135	6	6	6	10	10	10	10	10	10	10	10	16	16	16	16	16	16	20	20	20
180	6	6	10	10	10	10	10	10	16	16	16	16	20	20	20	20	25	25	25	25
Electronic ballast
36	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
55	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
66	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	10	10	10
91	6	6	6	6	6	6	10	10	10	10	10	10	10	10	10	10	16	16	16	16
MCB rating D tripping curve
Ferromagnetic ballast
18	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
26	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
35/36	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
55	6	6	6	6	6	6	6	6	6	6	6	6	6	6	10	10	10	10	10	10
91	6	6	6	6	6	6	6	6	6	6	10	10	10	10	10	10	16	16	16	16
131	6	6	6	6	6	6	10	10	10	10	10	10	16	16	16	16	16	16	16	20
135	6	6	6	6	6	6	10	10	10	10	10	16	16	16	16	16	16	20	20	20
180	6	6	6	6	10	10	10	10	16	16	16	16	20	20	20	20	25	25	25	25
Electronic ballast
36	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
55	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
66	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	10	10	10
91	6	6	6	6	6	6	6	6	6	6	10	10	10	10	10	10	10	16	16	16

Fig. N55: 'Low pressure sodium (with PF correction) - Vac = 230 V

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Lamp power (W)	Number of lamps per circuit
	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20
MCB rating C tripping curve
Ferromagnetic ballast
50	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	10	10	10	10
70	6	6	6	6	6	6	6	6	6	6	10	10	10	10	10	10	10	16	16	16
100	6	6	6	6	6	6	6	6	10	10	10	10	10	16	16	16	16	16	16	16
150	6	6	10	10	10	10	10	10	6	16	16	16	16	16	16	20	20	20	25	25
250	6	10	16	16	16	20	20	20	20	20	20	25	25	25	32	32	32	32	40	40
400	10	16	20	25	32	32	32	32	32	32	32	40	40	40	50	50	50	50	63	63
1000	16	32	40	50	50	50	50	63	63	-	-	-	-	-	-	-	-	-	-	-
Electronic ballast
35	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
50	6	6	6	6	6	6	6	6	6	6	6	6	6	10	10	10	10	10	10	10
100	6	6	6	6	6	6	6	6	10	10	10	10	10	10	16	16	16	16	16	16
MCB rating D tripping curve
Ferromagnetic ballast
50	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	10	10	10	10
70	6	6	6	6	6	6	6	6	6	6	10	10	10	10	10	10	10	16	16	16
100	6	6	6	6	6	6	6	6	10	10	10	10	10	16	16	16	16	16	16	16
150	6	6	6	6	6	10	10	10	10	16	16	16	16	16	16	20	20	20	25	25
250	6	6	10	10	16	16	16	16	16	20	20	25	25	25	32	32	32	32	40	40
400	6	10	16	16	20	20	25	25	25	32	32	40	40	40	50	50	50	50	63	63
1000	10	20	32	32	40	40	50	63	63	-	-	-	-	-	-	-	-	-	-	-
Electronic ballast
35	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
50	6	6	6	6	6	6	6	6	6	6	6	6	6	10	10	10	10	10	10	10
100	6	6	6	6	6	6	6	6	10	10	10	10	10	10	16	16	16	16	16	16

Fig. N56: High pressure sodium (with PF correction) - Vac = 230 V

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Lamp power (W)	Number of lamps per circuit
	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20
MCB rating C tripping curve
Ferromagnetic ballast
35	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
70	6	6	6	6	6	6	6	6	6	6	10	10	10	10	10	10	10	16	16	16
150	6	6	10	10	10	10	10	10	10	16	16	16	16	16	16	20	20	20	25	25
250	6	10	16	16	16	20	20	20	20	20	20	25	25	25	32	32	32	32	40	40
400	6	16	20	25	25	32	32	32	32	32	32	40	40	40	50	50	50	50	63	63
1000	16	32	40	50	50	50	50	63	63	63	63	63	63	63	63	63	63	63	63	63
1800/2000	25	50	63	63	63	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
Electronic ballast
35	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
70	6	6	6	6	6	6	6	6	6	6	6	6	10	10	10	10	10	10	10	10
150	6	6	6	10	10	10	10	10	10	10	16	16	16	16	16	16	16	20	20	20
MCB rating D tripping curve
Electronic ballast
35	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
70	6	6	6	6	6	6	6	6	6	6	6	10	10	10	10	10	10	16	16	16
150	6	6	6	6	6	10	10	10	10	16	16	16	16	16	16	20	20	20	25	25
250	6	6	10	10	16	16	16	16	16	20	20	25	25	25	32	32	32	32	40	40
400	6	10	16	16	20	20	25	25	25	32	32	40	40	40	50	50	50	50	63	63
1000	16	20	32	32	40	50	50	63	63	-	-	-	-	-	-	-	-	-	-	-
1800	16	32	40	50	63	63	-	-	-	-	-	-	-	-	-	-	-	-	-	-
2000	20	32	40	50	63	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
Electronic ballast
35	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
70	6	6	6	6	6	6	6	6	6	6	6	6	10	10	10	10	10	10	10	10
150	6	6	6	6	6	6	6	10	10	10	16	16	16	16	16	16	16	20	20	20

Fig. N57: <Metal halide (with PF correction) - Vac = 230 V

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Lamp power (W)	Number of lamps per circuit
	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20
MCB rating C tripping curve
1800	16	32	40	50	50	50	50	63	63	-	-	-	-	-	-	-	-	-	-	-
2000	16	32	40	50	50	50	50	63	63	-	-	-	-	-	-	-	-	-	-	-
MCB rating D tripping curve
1800	16	20	32	32	32	32	50	63	63	-	-	-	-	-	-	-	-	-	-	-
2000	16	25	32	32	32	32	50	63	-	-	-	-	-	-	-	-	-	-	-	-

Fig. N58: <Metal halide (with ferromagnetic ballast and PF correction) - Vac = 400 V

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Overload of the neutral conductor

The risk
In an installation including, for example, numerous fluorescent tubes with electronic ballasts supplied between phases and neutral, a high percentage of 3^rd harmonic current can cause an overload of the neutral conductor. Figure N59 below gives an overview of typical H3 level created by lighting.

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Lamp type	Typical power	Setting mode	Typical H3 level
Incandescend lamp with dimmer	100 W	Light dimmer	5 to 45 %
ELV halogen lamp	25 W	Electronic ELV transformer	5 %
Fluorescent tube	100 W	Magnetic ballast	10 %
	< 25 W	Electronic ballast	85 %
	> 25 W	+ PFC	30 %
Discharge lamp	100 W	Magnetic ballast	10 %
		Electrical ballast	30 %

Fig. N59: Overview of typical H3 level created by lighting

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The solution
Firstly, the use of a neutral conductor with a small cross-section (half) should be prohibited, as requested by Installation standard IEC  60364, section 523–5–3.
As far as overcurrent protection devices are concerned, it is necessary to provide
4-pole circuit-breakers with protected neutral (except with the TN-C system for which the PEN, a combined neutral and protection conductor, should not be cut).
This type of device can also be used for the breaking of all poles necessary to supply luminaires at the phase-to-phase voltage in the event of a fault.
A breaking device should therefore interrupt the phase and Neutral circuit simultaneously.

Leakage currents to earth

The risk
At switch-on, the earth capacitances of the electronic ballasts are responsible for residual current peaks that are likely to cause unintentional tripping of protection devices.

Two solutions
The use of Residual Current Devices providing immunity against this type of impulse current is recommended, even essential, when equipping an existing installation
(see Fig.N60).

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Fig. N60: s.i. residual current devices with immunity against impulse currents (Merlin Gerin brand)

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For a new installation, it is sensible to provide solid state or hybrid control devices (contactors and remote-control switches) that reduce these impulse currents (activation on voltage passage through zero).

Overvoltages

The risk
As illustrated in earlier sections, switching on a lighting circuit causes a transient state which is manifested by a significant overcurrent. This overcurrent is accompanied by a strong voltage fluctuation applied to the load terminals connected to the same circuit.
These voltage fluctuations can be detrimental to correct operation of sensitive loads (micro-computers, temperature controllers, etc.)
The Solution
It is advisable to separate the power supply for these sensitive loads from the lighting circuit power supply.

Sensitivity of lighting devices to line voltage disturbances

Short interruptions

• The risk

Discharge lamps require a relighting time of a few minutes after their power supply has been switched off.

• The solution

Partial lighting with instantaneous relighting (incandescent lamps or fluorescent tubes, or “hot restrike” discharge lamps) should be provided if safety requirements so dictate. Its power supply circuit is, depending on current regulations, usually distinct from the main lighting circuit.

Voltage fluctuations

• The risk

The majority of lighting devices (with the exception of lamps supplied by electronic ballasts) are sensitive to rapid fluctuations in the supply voltage. These fluctuations cause a flicker phenomenon which is unpleasant for users and may even cause significant problems. These problems depend on both the frequency of variations and their magnitude.
Standard IEC 61000-2-2 (“compatibility levels for low-frequency conducted disturbances”) specifies the maximum permissible magnitude of voltage variations as a function of the number of variations per second or per minute.
These voltage fluctuations are caused mainly by high-power fluctuating loads (arc furnaces, welding machines, starting motors).

• The solution

Special methods can be used to reduce voltage fluctuations. Nonetheless, it is advisable, wherever possible, to supply lighting circuits via a separate line supply.
The use of electronic ballasts is recommended for demanding applications (hospitals, clean rooms, inspection rooms, computer rooms, etc).

Developments in control and protection equipment

The use of light dimmers is more and more common. The constraints on ignition are therefore reduced and derating of control and protection equipment is less important.
New protection devices adapted to the constraints on lighting circuits are being introduced, for example Merlin Gerin brand circuit-breakers and modular residual current circuit-breakers with special immunity, such as s.i. type ID switches and Vigi circuit-breakers. As control and protection equipment evolves, some now offer remote control, 24-hour management, lighting control, reduced consumption, etc.