Definition of Protection Devices at the Start of the Line
Original instructions
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Introduction
It is recommended that you install a protection device at the start of the line on the power supply network, including these elements:
Choice of Line Circuit Breaker
Consider these factors when you choose the size of the line circuit breaker:
The choice of minimum circuit breaker size is made according to these rules:
NOTE: Protect all poles of the main power line by at least fuses or breakers rated 15 A for North America and 16 A for other countries.
This graph shows an example of characteristics provided by a circuit breaker manufacturer:
Choice of Line Fuse
When you choose the size of the line fuse, consider:
The choice of minimum fuse size is made according to these rules:
Power Supply Characteristics
This table gives a synthesis of the current characteristics needed to define the minimum size of the circuit breaker and fuse for a given power supply module:
Power Supply Module
nominal input current Irms
signaling current I(1)
current characteristic
It
I2t
BMXCPS2000
(100...240 Vac)
at 115 Vac
0.61 A
–
–
–
at 120 Vac
–
30 A
0.03 As
0.5 A2s
at 240 Vac
0.31 A
60 A
0.06 As
2 A2s
BMXCPS2010
(24 Vdc)
at 24 Vdc
1 A
30 A
0.15 As
0.6 A2s
BMXCPS3020(H)
(24...48 Vdc)
at 24 Vdc
1.65 A
30 A
0.2 As
1 A2s
at 48 Vdc
0.83 A
60 A
0.3 As
3 A2s
BMXCPS3500(H)
(100...240 Vac)
at 115 Vac
1.04 A
–
–
–
at 120 Vac
–
30 A
0.05 As
1 A2s
at 240 Vac
0.52 A
60 A
0.07 As
3 A2s
BMXCPS3540T
(125 Vdc)
at 125 Vdc
0.36 A
30 A
0.05 As
2 A2s
BMXCPS4002(H)
(100...240 Vac)
at 115 Vac
1.1 A
30 A
0.1 As
1 A2s
at 120 Vac
–
–
–
–
at 240 Vac
0.55 A
60 A
0.15 As
4 A2s
BMXCPS4022(H)
(24...48 Vdc)
at 24 Vdc
1.9 A
60 A
0.05 As
0.4 A2s
at 48 Vdc
1 A
60 A
0.08 As
1.9 A2s
BMXCPS3522(H)
(125 Vdc)
at 125 Vdc
0.6 A
60 A
0.025 As
0.15 A2s 
1
values at initial power-up and at 25 °C (77 °F)