Translation of CT classes between IEC and ANSI 2

[brcbwsc]

I need some way of translate IEC CT class 0,2 to an ANSI Class C??? are there any standard way of doing this?

 

[scottf]

You're trying to compare a metering accuracy class to a protection accuracy class. The closest IEEE accuracy to the IEC 0.2 class would be the IEEE class 0.15 or 0.3.

IEC defines the burden as a VA, i.e. Cl. 0.2 - 15 VA. IEEE defines burden as impedance, i.e., 0.3B1.8 (up to 1.8 ohms).

 

[cuky2000]

Here is a rough equivalence for selection of Instrument transformers (CTs & PTs) by application in accordance with IEC and equivalent with ANSI/IEEE.

---------------------------------------------------------------------
Application IEC Class ANSI Class
---------------------------------------------------------------------
Precision measurement & calibartion 0.1 0.3
Accurate pwr & tariff metering 0.2 0.3
Tariff & accurate measuring instruments 0.5 0.6
Industrial Meters: V, I, P, meters 1 1.2
Ammeter or volmeters, overcurrent/V relay 3 1.2
Current Transf. protective cores 5P,10P C,T
----------------------------------------------------------------------
_{SOURCE: ABB Switchgear Manual, 10th edition.}

 

[scottf]

cuky2000-

That info is slightly dated, whereas the IEEE equal for the first 2 IEC classes listed is the 0.15 class.