6.3
Fastening
6.4
Mounting instructions
6.5
Shielded measuring current transformer variants
When used in outgoing circuits with high load or inrush currents, local saturations of the magnet-
ic core material of the measuring current transformers can occur. It is therefore recommended to
use the shielded P versions to prevent nuisance tripping.
The values are listed in the technical data and refer to a correctly selected internal diameter of the
measuring current transformer: d2 ≥ 2 x d1 (cable diameter).
a
b
c
CTBC20(P), CTBC35(P)
a
b
c
CTBC60(P)
a
b
c
CTBC120(P) ... CTBC210(P)
Type
a
b
c
CTBC20(P) 31.4 49 2 x ø 5.5
CTBC35(P) 49.8 49 2 x ø 5.5
CTBC60(P)
56
66 3 x ø 6.5
CTBC120(P) 103 81 4 x ø 6.5
CTBC210(P) 180 98 4 x ø 6.5
All current-carrying cables must be routed together through
the measuring current transformer. Never route an existing
protective conductor through the measuring current trans-
former.
PE
L1
L2
L3
N
P1 (K): YE
P2 (L): GY
*
*
The primary conductors may only be bent from the specified
minimum distance. The minimum bending radius specified by
the manufacturers must be observed.
* Distance to 90° angle = 2 x external diameter
The cables must be centred in the measuring current trans-
former.
To prevent nuisance tripping, the measuring current trans-
formers should not be completely filled with cables. The inter-
nal diameter of the current transformer should be at least
twice the diameter of the conductor bundle to be measured.
The following applies: d2 ≥ 2 x d1
16 MRCDB423_D00396_01_M_XXEN/06.2021
Measuring current transformers
