As per IEC 61869 “Instrument transformers – Inductive voltage transformers”

Accuracy class	Ratio error from0.8Un to 1.2Un	Déphasage de 0,8Un to 1,2Un
0,1	0,1%	5′
0,2	0,2%	10′
0,5	0,5%	20′
1	1%	40′
3	3%	–

Ratio errors and phase displacement of metering classes

Accuracy class	Ratio error from 0,05Un to voltage factor x Un	Phase displ. from 0,05Un to voltage factor x Un
3P	3%	120′
6P	6%	240′

Ratio errors and phase displacement of protection classes