What Reason for RCD Working on 0degrees, not 180degrees?

[acvc]

Tested an RCD today, 30mA.

15mA time : >1999ms
30mA : 44.1ms on 0degrees / 53.8 on 180degrees
150mA : 15.8 on 0degrees / >40ms on 180degrees.

I did this four times, similar results each time. Zs at that socket 0.91ohms.

I don't understand why an RCD would trip on one angle of the phase and not the other.

Can anyone fill me in?

Thanks in advance

 

[Adam W]

Could be a faulty rcd. Surely that's why we do testing?

 

[Hawk81]

i would change RCD and test again. sounds like a faulty RCD

 

[GStueyXR]

Seen it before, changed RCD, same problem. Changed again twice, same problem. Stopped buying hagar, solved !

 

[robd]

A mate had the same problem on a Volex RCD, using his Fluke testers which had just been calibrated, tried it with my megger, no problem. Took the flukes back to Neweys, they sent them off and the testers were faulty...and they had been fine before they were calibrated.