Specifications 61
Common CT Specifications
Type:
voltage output, integral burden resistor
Output Voltage at Rated Current:
0.33333 Vac (one-third volt)
Standard CT Wire Length:
2.4 m (8 feet)
Optional CT Wire Length:
up to 30 m (100 feet)
Split-Core CTs
Also called “opening” current transformers. These are UL recognized under UL file numbers
E96927 or E325972: CTM-0360-
xxx
, CTS-0750-
xxx
, CTS-1250-
xxx
, CTS-2000-
xxx
, where
xxx
indicates the full scale current rating between 0005 and 1500 amps.
The accuracy of the split-core CTs are specified from 10% to 100% of rated AC current. The
phase angle is specified at 50% of rated current (amps). Some low current split-core CTs have
unspecified phase angle errors.
Model
Inside
Diameter
Rated Amps (-xxx)
Accuracy /
Phase Angle
Maximum
Amps
CTM-0360-xxx
0.30" (7.5 mm)
5, 15, 30, 50, 70
±1% / <2°
100
CTS-0750-xxx
0.75” (19.0 mm)
5, 15, 20, 30, 50
±1% / not spec.
200
CTS-0750-xxx
0.75” (19.0 mm)
70, 100, 150, 200
±1% / <2°
200
CTS-1250-xxx
1.25” (31.7 mm)
70, 100
±1% / not spec.
600
CTS-1250-xxx
1.25” (31.7 mm)
150, 200, 250, 300, 400, 600
±1% / <2°
600
CTS-2000-xxx 2.00” (50.8 mm)
600, 800, 1000, 1200, 1500
±1% / <2°
1500
Table 15: Split-core CTs
Split-Core Bus Bar CTs
These current transformers are referred to as “bus bar” CTs because they are available in larger
and custom sizes appropriate for use with bus bars or multiple large conductors. These are UL
recognized under UL file number E325972:
CTB-
www
X
hhh
-
xxx
, where
www
and
hhh
indicate
the width and height in inches, and
xxx
indicates the full scale current rating.
The accuracy of the split-core bus bar CTs is specified from 10% to 100% of rated current. The
phase angle is specified at 50% of rated current (amps).
Model
Opening
Rated
Amps
Accuracy /
Phase Angle
Maximum
Amps
CTB-1.5X3.5-0600
1.5" x 3.5" (38.1 mm x 88.9 mm)
600
±1.5% / <1.5°
750
CTB-4.0X4.0-0800
4.0" x 4.0" (101.6 mm x 101.6 mm)
800
±1.5% / <1.5°
1000
CTB-4.0X4.0-1200
4.0" x 4.0" (101.6 mm x 101.6mm)
1200
±1.5% / <1.5°
1500
CTB-4.0X4.0-2000
4.0" x 4.0" (101.6 mm x 101.6 mm)
2000
±1.5% / <1.5°
2500
CTB-4.5X4.0-3000
4.5" x 4.0" (114.3 mm x 101.6 mm)
3000
±1.5% / <1.5°
3750
CTB-wwwXhhh-xxxx
Custom (www by hhh inches)
xxxx
±1.5% / <1.5°
4000
Table 16: Split-core Bus Bar CTs
Solid-Core CTs
Also called “toroid” or “donut” current transformers. These are UL recognized under UL
file number E96927: CTT-0750-100N, CTT-1250-400N, CTT-0300-030N, CTT-0500-060N,
CTT-1000-200N, CTT-0300-005N, CTT-0300-015N, CTT-0500-050N, CTT-0500-030N,
CTT-0500-015N, CTT-0750-070N, CTT-0750-050N, CTT-0750-030N, CTT-1000-150N,
CTT-1000-100N, CTT-1000-070N, CTT-1000-050N, CTT-1250-300N, CTT-1250-250N,
CTT-1250-200N, CTT-1250-150N, CTT-1250-100N, CTT-1250-070N.
