77
3
Selection and application
3-10 Protecting SSCs using MCCBs or MMSs
Table 3-23 Protecting SSCs for heater circuits using MCCB (short-circuit region)
Rated voltage
SSC type
MCCB
Fuse
Type
Icu (kA)
Type
I
2
t
u
10
3
A
2
S)
Icu (kA)
230V AC
SS03
SS08
SS20
SS30
SS40
SS50
SS80
SS120
BW32SAQ-3P005
BW32SAQ-3P010
BW32SAQ-3P040
BW32SAQ-3P060
BW32SAQ-3P080
BW63SAQ-3P120
BW125JAQ-3P450
BW250JAQ-3P600
5
5
5
5
10
10
50
50
CR2LS-10
CR2LS-10
CR2LS-30
CR2LS-50
CR2LS-70
CR2LS-100
CR2L-140
CR2L-200
0.04
0.04
0.35
0.85
2.3
4.0
7.0
17
100
100
100
100
100
100
100
100
400V AC
SS30
H
SS50
H
SS80
H
SS120
H
BW32SAQ-3P060
BW63SAQ-3P120
BW125JAQ-3P450
BW250JAQ-3P600
2.5
7.5
30
30
CR6L-50
CR6L-100
CR6L-200
CR6L-200
1.8
7.0
30
30
100
*1
100
*1
100
*1
100
*1
.OTES s )NDICATES33#SMOUNTEDONSTANDARDCOOLINGlNS
s 5SEAN"7*!10FOR33
applications with through current at or below 100A.
s 5SEATWOPOLE-##"INSINGLEPHASECIRCUIT33#APPLICATIONSORATHREEPOLE-##"INTHREEPHASECIRCUIT33#APPLICATIONS
*1 Breaking capacity at 600V AC.
Solid-state contactor
3-10 Protecting SSCs using MCCBs or
MMSs
When an MCCB is used to protect a solid-state contactor
(SSC), protection over the entire range of its overload
region to the short-circuit region would be difficult to achieve
with an MCCB alone. To ensure complete protection of the
SSC with an MCCB, the MCCB should be combined with a
thermal overload relay and current-limiting fuse, or any other
appropriate protective device.
3-10-1 For heater (resistive load) circuits
Table 3-23 lists recommended combinations of MCCBs and
SSCs for heater control purposes. These combinations enable
MCCBs to protect SSCs in region B, and current-limiting
fuses to protect in region C (Fig. 3-33). The SSCs can thus be
protected against short-circuit currents two times higher than
the SSC’s rated current and lower than the current-limiting
fuse breaking capacity with MCCBs.
