Page 214 - B_ELSB_Cat_2022_01_MCBs

1/214 ELECTRICAL INSTALL ATION SOLUTIONS FOR BUILDINGS - TECHNICAL DETAILS 9AKK 107991 A8329
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MCBs technical details
Particular supply sources and loads

Lighting circuit protection may be supplied directly by the device manufacturer.
Selection of circuit-breakers for the protection of lighting Considering the utilization current, it is important to select
circuit and calculation of their rated current the version of the breaker with a rated current just above
To select the correct circuit-breaker for use in the protection the value calculated, defining the cable cross-section
of lighting circuits you need to know the type of load based accordingly. The tables below show the rated current values
on which you will work out the breaker’s rated current. The of the circuit-breakers to be used according to the type
protection circuit utilization current can be calculated simply and power of the device connected.
starting with the rated power and the lighting voltage, or it

Table 1 High pressure discharge lamps
230 V and 400 V AC three-phase with or without power factor correcting capacitors, star or delta connection

Mercury vapour fluorescent lamp Pw [W] <700 <1000 <2000
I [A] 6 10 16
Mercury vapour metal halogen lamp Pw [W] <375 <1000 <2000
I [A] 6 10 16
High pressure sodium Pw [W] <400 <1000
discharge lamp
I [A] 6 16
Table 2 Fluorescent lamps
230 VAC single-phase/three-phase with neutral (400 V), with star connection.
The tables indicate the rated current of the circuit-breakers according to the lamp power and type of power supply.

Example of calculation
- Starter dissipated power: 25% of lamp power
- Reference temperature: 30 and 40 °C according to circuit-breaker
- Power factor: lamp without capacitors cos φ=0.6
lamp with capacitors cos φ=0.86
Method of calculation
- IB = (PL * n°L * KST * KC) / (Un * cos φ) where: - Un = rated voltage 230 V
- cos φ = power factor
- PL = lamp power
- n°L = number of lamps per phase
- KST = 1.25
- KC = 1 for star connection and 1.732
for delta connection

Type of lamp Tube diss. pwr. [W] Number of lamps per phase
Single 18 4 9 14 29 49 78 98 122 157 196 245 309 392 490
without 36 2 4 7 14 24 39 49 61 78 98 122 154 196 245
capacitors
58 1 3 4 9 15 24 30 38 48 60 76 95 121 152
Single with 18 7 14 21 42 70 112 140 175 225 281 351 443 562 703
capacitors 36 3 7 10 21 35 56 70 87 112 140 175 221 281 351
58 2 4 6 13 21 34 43 54 69 87 109 137 174 218
Double with 2x18=36 3 7 10 21 35 56 70 87 112 140 175 221 281 351
capacitors
2x36=72 1 3 5 10 17 28 35 43 56 70 87 110 140 175
2x58=116 1 2 3 6 10 17 21 27 34 43 54 68 87 109
I [A] - 2P and 4P circuit-breakers 1 2 3 6 10 16 20 25 32 40 50 63 80 100
n