I'm in the 'prove they do something' camp.   I haven't seen amazing stories of how wonderful they are from America (where they've been mandated on bedroom branch circuits for years). And the amazing John Ward has tried and failed to trip one using series and parallel arcs of a type that seem to be reasonably accurate to my eyes.  (although a slow overheating connection with occasional bursts of FZZZZZTTTTT arcing under load may be what they're looking for... and to my knowledge that's hard to simulate)


In short, i think they're overpriced for something with no guarantee that it will do any good.


Edit: plus the fact, I absolutely do NOT trust electronics in a consumer unit. I never rely on RCD protection from RCBOs... or even modern RCDs. I install my circuits as if they weren't there. . I see too many 'electricians' taking a horribly relaxed attitude to earthing and bonding because 'there's an RCD'


The fact that bonding isn't related to YOUR electrical installation alone, but the rest of the network... seems to escape them.Open PEN on the supply side, and your extraneous metalwork is at a different potential to your electric kettle... which you're filling at the sink :\,\N,\N 1037"

I'm in the 'prove they do something' camp.   I haven't seen amazing stories of how wonderful they are from America (where they've been mandated on bedroom branch circuits for years). And the amazing John Ward has tried and failed to trip one using series and parallel arcs of a type that seem to be reasonably accurate to my eyes.  (although a slow overheating connection with occasional bursts of FZZZZZTTTTT arcing under load may be what they're looking for... and to my knowledge that's hard to simulate)


In short, i think they're overpriced for something with no guarantee that it will do any good.


Edit: plus the fact, I absolutely do NOT trust electronics in a consumer unit. I never rely on RCD protection from RCBOs... or even modern RCDs. I install my circuits as if they weren't there. . I see too many 'electricians' taking a horribly relaxed attitude to earthing and bonding because 'there's an RCD'


The fact that bonding isn't related to YOUR electrical installation alone, but the rest of the network... seems to escape them.Open PEN on the supply side, and your extraneous metalwork is at a different potential to your electric kettle... which you're filling at the sink :\,\N,\N 1037"