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WIRING ACCESSORIES AND SINGLE PHASE DISTRIBUTION
PG00400018U – March 2012
6kA Miniature Circuit Breakers (MCBs) technical Data
Eaton’s range of 6kA high performance Miniature Circuit Breakers
(MCBs) are manufactured to IEC/EN 60898, meeting the latest UK,
European and International standards, with ratings from 2A to 63A
as standard.
DIN rail mountable and suitable for use with both pin and comb
type busbar systems, Eaton’s MCBs are suitable for use on
230/240 V, AC systems and are calibrated for use at 40
o
C
. These
devices suite with the other modular devices including RCBOs,
RCCBs and Isolators, for use within Eaton’s MEM consumer units
and a wide range of other applications.
The Eaton 6kA MCBs are fitted with box clamp terminals suitable
for use with cables up to 25mm
2
.
The Eaton 6kA miniature circuit breakers are available with both
B and C characteristic curves as standard. Type B MCBs are most
commonly used in domestic applications, however the use of type
C devices may be desirable e.g. on lighting circuits where high
switching surges are involved. Type D devices are not commonly
used in other than industrial applications.
IEC/EN 60898
Instantaneous
Typical
Eaton 6kA
Type
Trip Current (x In)
Application
MCB Type
B
3 to 5
Domestic
EAD B
C
5 to 10
Commercial
EAD C
Light Industrial
D
10 to 20
General
–
Industrial
Type B:
Suitable for general, domestic and commercial installations
having little or no switching surges
Type C:
Suitable for general use in commercial or industrial
applications where the greater use of fluorescent lighting and small
motors can produce switching surges, which may cause nuisance
tripping of type B breakers.
Type D:
Suitable for General Industrial applications where there are
a lot of high inrush switching surges associated with equipment
such as transformers, large motors, welding and X ray equipment.
Earth fault loop impedance’s (Zs) to provide compliance
with BS 7671
The wiring regulations BS 7671 makes specific reference to MCB
types and the maximum earth loop impedance allowable to meet
the required disconnection times.
It can be seen that it is much easier to achieve adequate
disconnection times with type B devices than it is with types C and
indeed type D devices.
Maximum earth fault loop impedance i.e. Zs ohms for final circuits
fed from Miniature Circuit Breakers MCBs or RCBOs with Uo of
230V, for instantaneous operation giving compliance with 0.4s
disconnection time of Reg 411.3.2.2 and 5s disconnection time
of 411.3.2.3
Table Zs Ohms
Device
Standard
2A
4A
6A
10A
13A
16A
20A
25A
32A
40A
45A
50A
63A
Type B MCB
BS EN 60898
23.00
11.50
7.67
4.60
3.54
2.88
2.30
1.84
1.44
1.15
–
0.92
0.73
Type C MCB
BS EN 60898
11.50
5.75
3.83
2.30
1.77
1.44
1.15
0.92
0.72
0.58
–
0.46
0.37
Type B RCBO BS EN 61009
–
–
7.67
4.60
–
2.88
2.30
1.84
1.44
1.15
1.02
–
–
Type C RCBO BS EN 61009
–
–
3.83
2.30
–
1.44
1.15
0.92
0.72
0.58
0.51
–
–
0.0005
]ces[ t
N
I / I
7200
3600
1200
600
300
120
60
30
10
5
2
1
0.5
0.2
0.1
0.05
0.02
0.005
0.01
0.002
0.001
50 40
30
20 15
109876 5 4 3
2
1
N
N
N
N
1
2
nt
N
N
4
5
7
6
3
I = 1.13 I : t > 1 h
t
I = 1.45 I : t < 1 h
2.55 I : t = 1- 60 s (I < 32A)
t = 1-120 s (I > 32A)
5 I : t < 0.1 s
N
10 I : t < 0.1 s
conventional non-tripping current
conventional tripping current
Type B: 3 I : t > 0.1 s
N
Type C: 5 I : t > 0.1 s
Tripping characteristic
nach EN 60898
N
7
5
6
4
3
3
2
1
C B
Tripping characteristic type B and C
Technical data
Switch and protection devices dimensions and data
12.5