As per IEC 61869 “Instrument transformers – current transformers”

Accuracy class	Error 0,05In	Error 0,2In	Error 0,5In	Error In	Error 1,2In
0,1	0,4%	0,2%	–	0,1%	0,1%
0,2	0,75%	0,35%	–	0,2%	0,2%
0,5	1,5%	0,75%	–	0,5%	0,5%
1	3%	1,5%	–	1%	1%
3	–	–	3%	–	3%

Ratio errors accuracy classes

Accuracy class	Phase displ. 0,05In	Phase displ. 0,2In	Phase displ. In	Phase displ. 1,2In
0,1	15′	8′	5′	5′
0,2	30′	15′	10′	10′
0,5	90′	45′	30′	30′
1	180′	90′	60′	60′
3	–	–	–	–

Phase displacement accuracy classes

Accuracy class	Error 0,01In	Error 0,05In	Error 0,2In	Error In	Error 1,2In	Composite error at rated accuracy limit current
0,2S	0,75%	0,35%	0,2%	0,2%	0,2%	–
0,5S	1,5%	0,75%	0,5%	0,5%	0,5%	–
5P	–	–	–	1%	–	5%
10P	–	–	–	3%	–	10%

Ratio errors classes S and protection

Accuracy class	Phase displ. 0,01In	Phase displ. 0,05In	Phase displ. 0,2In	Phase displ. In	Phase displ. 1,2In
0,2S	30′	15′	10′	10′	10′
0,5S	90′	45′	30′	30′	30′
5P	–	–	–	60′	–
10P	–	–	–	–	–

Phase displacement classes S and protection