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8.8. INtrINSIC UNCErtAINty ANd oPErAtING UNCErtAINty
C.A 6550 and C.A 6555 megohmmeters comply with standard IEC-61557, which requires that the operating uncertainty, called
B, be less than 30%.
In insulation measurements, B = ± ( |A| + 1,15
√
E
1
² + E
2
² + E
3
² )
with
A = intrinsic uncertainty
E
1
= influence of the reference position ±90°.
E
2
= influence of the supply voltage within the limits indicated by the manufacturer.
E
3
= influence of the temperature between 0 and 35°C.
