I checked out John Ward's great Youtube trilogy on Arc Fault Detection Devices
(quote JW:
'Arc Fault Deception Devices' ![Grin ;D](https://www.eevblog.com/forum/Smileys/default/xgrin.gif.pagespeed.ic.QVVz6XIT20.png)
)
and there is no way I would have a 3 way 'all in one' combo wasting 3 Din rail spaces,
eventually nuisance tripping, or not at all, once the unit ages a bit and or exposed to hot/cold/dust/moisture snafus
If they become compulsory here, I'll opt for a larger main board or addon if necessary with separate module AFDDs or AFCDs,
so I can test and get them swapped out if they are duds/placebos,
and leave the working MCB and RCDs or RCBO combos alone to do their job.
![ThumbsUp :-+](https://www.eevblog.com/forum/Smileys/default/icon_smile_thumbsup.gif.pagespeed.ce._JElyJQqdB.gif)
..and save serious dollars not having to pay out on clapped 3 space 'three in ones'
![Phew :phew:](https://www.eevblog.com/forum/Smileys/default/phew.gif.pagespeed.ce.n2uLOVFYMP.gif)