Do we have to fit AFDD's in domestic installations?

[HappyHippyDad]

I can't find any really up to date threads on whether we have to fit AFDD's.

I am specifically talking about in a domestic premise. I can see that 421.1.7 shows where an AFDD HAS to be fitted (i.e in one of the 4 bullet points), but then it says below ( the bullet points) it is 'recommended' that AFDD's are fitted in ALL premises for socket outlets.

The Napit Webinar (02/11/2022) kind of skips lightly over this point. At 11 mins and 25 seconds he says something along the lines of 'it is up to the designer whether to use the recommendation of using AFDD's'.

It clearly is not mandatory otherwise the reg would not state the 4 examples of where it actually is mandatory. So it is actually optional, but there isn't any criteria given to help you decide whether or not you should fit one.

Does anyone have any clarification on this?

 

[newfutile]

If it was a serial arc then no, low current arcs are not detected,in the USA maybe as there current will be twice ours for the same wattage

 

[brianmoooore]

May have started with a serial arc, but there's enough carbon there to leak sufficient current to the cpc to trip a RCD.

 

[mainline]

May have started with a serial arc, but there's enough carbon there to leak sufficient current to the cpc to trip a RCD.

Maybe not before catching the house on fire, though.

 

[7029 dave]

Dave tight is better than any torque screwdriver or any AFDD's

 

[Dustydazzler]

DELTIGHT

 

[Midwest]

RCD would have taken care of the above.

Not continuity between cpc & line in this fault.

 

[LukeD]

Ive got a EICR to do today that requires measuring the building height ( floors ) to see if it come under HRRB regs and needs AFD’s

They better hope its under 18m !! Otherwise its 5x new AFD and thats not cheap !

 

[Markyd]

I live in a timber clad and old oak barn conversion. It has been fully rewired to a high standard. Because of multiple buildings, we have multiple CUs, all Hager. We recently decided to fit AFDDs to all areas where we have any kind of fire risk concern and had no difficulty getting them via our trade accounts. What is interesting is the resistance to using them which I think is largely driven by cost. We paid £102 each, plus fitting and testing and some other necessary changes due to CU space. This is not a trivial sum for AFDD multiples in domestic properties. I am a developer, not a qualified electrician, though I am familiar with the regs. If the regulatory authorities think AFDDs will materially reduce fire risk then having vague wording like "recommended" is ridiculous. Eventually insurance companies will drive this. I specify them in developments now. They make sense to me.

NOT HAGER my god anything but them....they dont even trip when they are nearly on fire

 

[davesparks]

Ive got a EICR to do today that requires measuring the building height ( floors ) to see if it come under HRRB regs and needs AFD’s

They better hope its under 18m !! Otherwise its 5x new AFD and thats not cheap !

Not necessarily 5x new AFDDs, that would only be a C3 and so a recommendation, not a requirement.

 

[davesparks]

NOT HAGER my god anything but them....they dont even trip when they are nearly on fire

That's a very extreme statement, do you have much evidence for this?

 

[pc1966]

They better hope its under 18m !! Otherwise its 5x new AFD and thats not cheap !

As @davesparks pointed out the guidance (BPG #4 page 20) codes this as C3 so not essential to change.

If they need a new CU for other reasons then you should be fitting AFDD due to the current regs requiring them, but not as an EICR-forced change.

 

[Markyd]

That's a very extreme statement, do you have much evidence for this?

Here you go Watch them all.....brilliant

 

[Simon47]

I've only watched the first of the videos, not a good showing to not detect some serious arcing.
I've seen the result of parallel arcing at church. We had a fuse blowing intermittently but couldn't find any cause. It was only when someone mentioned a socjet not working that I found a length of T&E going through a 3ft thick wall where the mice had been at it - and about 6" was burned away from arcing, just like the test the video showed the Hager device not detecting.