Intro

IEEE C57.13-2016, Table 11: Standard multi-ratio current transformer taps*


600:5
Ratio 
1200:5
Tap
2000:5
Ratio
3000:5
Tap 
4000:5
Ratio 
Tap
Ratio
Tap
Ratio
Tap
Ratio
5000:5
Tap
50:5
X2-X3
100:5
X2-X3
300:5
X3-X4
300:5
X3-X4
500:5
X1-X2
500:5
X2-X3
100:5
X1-X2
200:5
X1-X2
400:5
X1-X2
500:5
X4-X5
1000:5
X3-X4
1000:5
X4-X5
150:5
X1-X3
300:5
X1-X3
500:5
X4-X5
800:5
X3-X5
1500:5
X2-X3
1500:5
X1-X2
200:5
X4-X5
400:5
X4-X5
800:5
X2-X3
1000:5
X1-X2
2000:5
X1-X3
2000:5
X3-X4
250:5
X3-X4
500:5
X3-X4
1100:5
X2-X4
1200:5
X2-X3
2500:5
X2-X4
2500:5
X2-X4
300:5
X2-X4
600:5
X2-X4
1200:5
X1-X3
1500:5
X2-X4
3000:5
X1-X4
3000:5
X3-X5
400:5
X1-X4
800:5
X1-X4
1500:5
X1-X4
2000:5
X2-X5
3500:5
X2-X5
3500:5
X2-X5
450:5
X3-X5
900:5
X3-X5
1600:5
X2-X5
2200:5
X1-X3
4000:5
X1-X5
4000:5
X1-X4
500:5
X2-X5
1000:5
X2-X5
2000:5
X1-X5
2500:5
X1-X4
5000:5
X1-X5
600:5
X1-X5
1200:5
X1-X5
3000:5
X1-X5

*Contact factory for customer specific ratio taps.

IEEE C57.13-2016, Table 8: Standard accuracy class for metering service and 
corresponding limits of transformer correction factors*


Accuracy
class








Voltage Transformers Current Transformers
90% to 100% rated voltage 100% rated current+ 10% rated current 5% rated current
Min Max Min Max Min Max Min Max
0.15S
-
-
0.9985
1.0015
-
-
0.9985
1.0015
0.15
0.9985
1.0015
0.9985
1.0015
-
-
0.9970
1.0030
0.3S
-
-
0.9970
1.0030
-
-
0.9970
1.0030
0.3
0.9970
1.0030
0.9970
1.0030
0.9940
1.0060
-
-
0.6
0.9940
1.0060
0.9940
1.0060
0.9880
1.0120
-
-
1.2
0.9880
1.0120
0.9880
1.0120
0.9760
1.0240
-
-

*Other accuracy requirements may be specified and should be included on the nameplate.
+For current transformers, the 100% rated current limit also applies to the current corresponding to the continuous thermal current rating factor.
IEEE C57.13-2016, Table 19: Standard VT burdens at 60 Hz
Burden
designation
Secondary
volt-amperes
Burden
power factor
W 12.5 0.10
X 25.0 0.70
M 35.0 0.20
Y 75.0 0.85
Z 200.0 0.85
ZZ 400.0 0.85
IEEE C57.13-2016, Table 10: Standard 5A secondary CT burdens*
Burden
designation
Resistance
(ohms)
Inductance
(millihenrys)
Impedance
(ohms)
Volt-
amperes
Power
factor
Metering burdens
E-0.04+ 0.04 0.0 0.04 1.0 1.0
E-0.2+ 0.20 0.0 0.20 5.0 1.0
B-0.1 0.09 0.116 0.1 2.5 0.9
B-0.2 0.18 0.232 0.2 5.0 0.9
B-0.5 0.45 0.580 0.5 12.5 0.9
B-0.9 0.81 1.040 0.9 22.5 0.9
B-1.8 1.62 2.080 1.8 45.0 0.9
Relaying burdens
B-1 0.5 2.3 1.0 25 0.5
B-2 1.0 4.6 2.0 50 0.5
B-4 2.0 9.2 4.0 100 0.5
B-8 4.0 18.5 8.0 200 0.5
*at 60 Hz
—I N S T R U M E N T T R A N S F O R M E R S
IEEE Standard Ratings