Resistive-type heating appliances and incandescent lamps (conventional or halogen)

From Electrical Installation Guide

Contents 1 Fluorescent lamps and related equipment 2 Standard tubular fluorescent lamps 3 Compact fluorescent lamps 4 Discharge lamps 5 Notes

The current demand of a heating appliance or an incandescent lamp is easily obtained from the nominal power Pn quoted by the manufacturer (i.e. cos φ = 1) (see Fig. A5).

Nominal power (kW)	Current demand (A)
	1-phase 127 V	1-phase 230 V	3-phase 230 V	3-phase 400 V
0.1	0.79	0.43	0.25	0.14
0.2	1.58	0.87	0.50	0.29
0.5	3.94	2.17	1.26	0.72
1	7.9	4.35	2.51	1.44
1.5	11.8	6.52	3.77	2.17
2	15.8	8.70	5.02	2.89
2.5	19.7	10.9	6.28	3.61
3	23.6	13	7.53	4.33
3.5	27.6	15.2	8.72	5.05
4	31.5	17.4	10	5.77
4.5	35.4	19.6	11.3	6.5
5	39.4	21.7	12.6	7.22
6	47.2	26.1	15.1	8.66
7	55.1	30.4	17.6	10.1
8	63	34.8	20.1	11.5
9	71	39.1	22.6	13
10	79	43.5	25.1	14.4

Fig.A5: Current demands of resistive heating and incandescent lighting (conventional or halogen) appliances

The currents are given by:

• 3-phase case: ^[1]

• 1-phase case: ^[1]

where U is the voltage between the terminals of the equipment.
For an incandescent lamp, the use of halogen gas allows a more concentrated light source. The light output is increased and the lifetime of the lamp is doubled.

Note: At the instant of switching on, the cold filament gives rise to a very brief but intense peak of current.

Fluorescent lamps and related equipment

The power Pn (watts) indicated on the tube of a fluorescent lamp does not include the power dissipated in the ballast.

The current is given by:

Where U = the voltage applied to the lamp, complete with its related equipment.

If no power-loss value is indicated for the ballast, a figure of 25% of Pn may be used.

Standard tubular fluorescent lamps

With (unless otherwise indicated):

• cos φ = 0.6 with no power factor (PF) correction^[2] capacitor
• cos φ = 0.86 with PF correction^[2] (single or twin tubes)
• cos φ = 0.96 for electronic ballast.

If no power-loss value is indicated for the ballast, a figure of 25% of Pn may be used.
Figure A6 gives these values for different arrangements of ballast.

Arrangement of lamps, starters and ballasts	Tube Power (W) [3]	Current (A) at 230 V			Tube Length (cm)
		Magnetic Ballast		Electronic Ballast
		Without PF Correction capacitor	With PF Correction capacitor
Single tube	18	0.20	0.14	0.10	60
	36	0.33	0.23	0.18	120
	58	0.50	0.36	0.28	150
Twin tubes	2 x 18		0.28	0.18	60
	2 x 36		0.46	0.35	120
	2 x 58		0.72	0.52	150

[3] Power in watts marked on tube

Fig. A6: Current demands and power consumption of commonly-dimensioned fluorescent lighting tubes (at 230 V-50 Hz)

Compact fluorescent lamps

Compact fluorescent lamps have the same characteristics of economy and long life as classical tubes. They are commonly used in public places which are permanently illuminated (for example: corridors, hallways, bars, etc.) and can be mounted in situations otherwise illuminated by incandescent lamps (see Fig. A7).

Type of lamp	Lamp power (W)	Current at 230 V (A)
Separated ballast lamp	10	0.080
	18	0.110
	26	0.150
Integrated ballast lamp	8	0.075
	11	0.095
	16	0.125
	21	0.170

Fig. A7: Current demands and power consumption of compact fluorescent lamps (at 230 V - 50 Hz)

Discharge lamps

The power in watts indicated on the tube of a discharge lamp does not include the power dissipated in the ballast.

Figure A8: gives the current taken by a complete unit, including all associated ancillary equipment.

These lamps depend on the luminous electrical discharge through a gas or vapour of a metallic compound, which is contained in a hermetically-sealed transparent envelope at a pre-determined pressure. These lamps have a long start-up time, during which the current Ia is greater than the nominal current In. Power and current demands are given for different types of lamp (typical average values which may differ slightly from one manufacturer to another).

Type of lamp (W)	Power demand (W) at 230 V 400 V	Current In(A)		Starting		Luminous efficiency (lumens per watt)	Average timelife of lamp (h)	Utilization
		PF not corrected 230 V 400 V	PF corrected  230 V 400 V	Ia/In	Period (mins)
High-pressure sodium vapour lamps
50	60	0.76	0.3	1.4 to 1.6	4 to 6	80 to 120	9000	Lighting of large halls Outdoor spaces Public lighting
70	80	1	0.45
100	115	1.2	0.65
150	168	1.8	0.85
250	274	3	1.4
400	431	4.4	2.2
1000	1055	10.45	4.9
Low-pressure sodium vapour lamps
26	34.5	0.45	0.17	1.1 to 1.3	7 to 15	100 to 200	8000 to 12000	Lighting of autoroutes Security lighting,station Platform, storage areas
36	46.5		0.22
66	80.5		0.39
91	105.5		0.49
131	154		0.69
Mercury vapour + metal halide (also called metal-iodide)
70	80.5	1	0.40	1.7	3 to 5	70 to 90	6000	Lighting of very large areas by     projectors (for example:     sports stadiums, etc.)
150	172	1.80	0.88				6000
250	276	2.10	1.35				6000
400	425	3.40	2.15				6000
1000	1046	8.25	5.30				6000
2000	2092     2052	16.50    8.60	10.50      6				2000
Mercury vapour + fluorescent substance (fluorescent bulb)
50	57	0.6	0.30	1.7 to 2	3 to 6	40 to 60	8000 to 12000	Workshops with very high     ceilings (halls, hangars) Outdoor lighting Low light output[4]
80	90	0.8	0.45
125	141	1.15	0.70
250	268	2.15	1.35
400	421	3.25	2.15
700	731	5.4	3.85
1000	1046	8.25	5.30
2000	2140    2080	15	11        6.1

[4] Replaced by sodium vapour lamps.
Note: these lamps are sensitive to voltage dips. They extinguish if the voltage falls to less than 50% of their nominal voltage, and will not re-ignite before cooling for approximately 4 minutes.
Note: Sodium vapour low-pressure lamps have a light-output efficiency which is superior to that of all other sources. However, use of these lamps is restricted by the fact that the yellow-orange colour emitted makes colour recognition practically impossible.

Fig. A8: Current demands of discharge lamps

Notes

1. ↑ ^{1.0 1.1} Ia in amps; U in volts. Pn is in watts. If Pn is in kW, then multiply the equation by 1,000
2. ↑ ^{2.0 2.1} “Power-factor correction” is often referred to as “compensation” in discharge-lighting-tube terminology.
   Cos φ is approximately 0.95 (the zero values of V and I are almost in phase) but the power factor is 0.5 due to the impulsive form of the current, the peak of which occurs “late” in each half cycle