Instrument Security Factor 1

[farale]

Hi,

What does the "1FS10" mean on nameplate of a current transformer?
"FS10" should be it's Instrument Security Factor and means after 10*Ip, the CT will saturate.
But what is the "1" before "FS"?
I have seen 3FS5, 0.5FS10, etc.
Are they based on IEC60044?

Thanks all

 

[farale]

is it the accuracy class?

 

[scottf]

That means accuracy class 1.0 (1% class) with a security factory of 10.