Bi and Omni directional RCD's how can one tell what has been fitted.

[ericmark]

(probably something to do with perceived risks to the device itself, even if I can't think what!)

I think the test button, and under fault conditions the electronics staying active after it has tripped?

 

[ebee]

I looked on the IEE forum Wiring and the regulations yesterday an seem like they are having a similar discussion about it.

 

[JohnW2]

I think the test button, and under fault conditions the electronics staying active after it has tripped?

For a start, I think that, these days, all these devices disable the test button circuitry when the device trips. However, as I've said,even if that were not the case, I don't see that having the test button circuitry (and, indeed, also all of the internal electronics) still powered after the device is tripped is no different/worse from having those things powered continuously for months or years during normal service.

1....

 

[JohnW2]

I looked on the IEE forum Wiring and the regulations yesterday an seem like they are having a similar discussion about it.

That doesn't surprise me. I've also just looked at the few comments which already exist in the DPC of Amd 3 - and, again, some of themreflect discussions we've been having here, particularly this one:

It is not clear what evidence there is to support the concerns raised by Beama. Having tried to replicate the problem with a selection of RCBOs I have found no issues. With a reverse power flow the tripping times were all within the expected range and no damage was observed when the RCBOs were reverse connected with the mains removed. The current flows backwards and forward in the same manner through the RCBO irrespective of the direction of the power. The only thing that changes is the phase relationship between the voltage and the current. As far as I can see RCBOs make a differential assessment of the current using ferrite ring and this measurement world not be significantly affected by the phase of the voltage. I do not have the privilege of a circuit diagram so can’t be absolutely certain that there is no detrimental effect on performance, it does seem unlikely that there is and the measurements I have made suggest that there is no mal effect. I observe only that the repeated operation of the RCD test button was possible after the RCBO had tripped. In practice this would not occur where the device is connected to a G98 or G99 device because the generator would be quickly disconnected after the RCBO has tripped. Perhaps Beama could share their findings. If there are devices that have been proved to have a problem could they be identified and flagged. Is this really a problem deserving an accelerated consultation process?

There are also a good few comments about the ('unfamiliar') concept of "power flow".

Kind Regards,John