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Discuss Type 'A' RCD test results in the Electrical Wiring, Theories and Regulations area at ElectriciansForums.net

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I just installed my first type 'A' RCD. When I tested it, I was amazed by the disconnection time. It was 148ms @ 1IΔn. Okay this is less than the required 300ms, and I know I take the 5IΔn for the report, but even so, this seems high to me.
Is this correct for Type A RCD, they are slower to respond than Type AC ?
 
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Baddegg

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I use a lot of fusebox stuff and you get use to the times when testing but I have noticed when install the type A the times are slightly higher than Ac’s....
 

Risteard

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I have found that typically Hager Type A RCDs (I haven't installed Type AC in years) have a slower operating time when tested on the Type AC setting than when tested on the Type A setting. I haven't been able to establish a good explanation for this.
 

pc1966

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I have found that typically Hager Type A RCDs (I haven't installed Type AC in years) have a slower operating time when tested on the Type AC setting than when tested on the Type A setting. I haven't been able to establish a good explanation for this.
I think that may be fairly common.

I tested some 'type AC' RCD FCUs with type A testing to see what would happen and in one phase/polarity they tripped faster and at lower current than expected going on 0.5*In in (from memory) 12ms or so, but slower other polarity slower but still meeting the 1*In times around the 140ms time. On type AC testing they were around the 28ms both phases.

I have no idea how universal that is as I just to see what might happen with some older kit that has not been updated to type A for the rectified style of load they feed.
 

happyhippydad

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I just installed my first type 'A' RCD. When I tested it, I was amazed by the disconnection time. It was 148ms @ 1IΔn. Okay this is less than the required 300ms, and I know I take the 5IΔn for the report, but even so, this seems high to me.
Is this correct for Type A RCD, they are slower to respond than Type AC ?
From the replies it sounds like you have your answer, however I have noticed that 'sometimes' RCD's react differently depending on if you test them, i.e. actually at the RCD or if you have tested at a socket, switch or light. Where did you test this one Jeremy? Oops I mean Michael 😉
 
I actually tested from socket, when I go back and retest, I'll do it properly this time from RCD according to Hager instructions (Thanks Westwood10) . Be interesting to see how this differs from socket.
 

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