AFDDs for single-socket circuits

[Selfmade]

Haven't been on here for a while, so sorry if this has been discussed before.

BS7671 2018 + A2 Regulation 421.1.7 recommends AFDDs for "single-phase AC circuits supplying socket outlets..." (requires in certain premises). My intention is that from September 27th I will recommend them to customers (in practice I already do in some situations) and require a signed waiver if they don't want the expense. At least I will do so for the actual Sockets Circuits - typically ring final, serving a number of sockets for general use and sometimes also fixed equipment via FCUs.

What I'm not sure about is circuits that serve just a single socket, such as a dedicated circuit for a fridge or an oven. In the case of a fridge, it will likely draw less than 2A, so an AFDD is unlikely to perform any useful function. In the case of an oven, one could justify cutting off the plug and connecting it via an FCU, in which case the circuit is no longer supplying a socket, yet with or without a socket it's still the same appliance and the same wiring. Yet in both cases if a socket is fitted an AFDD is recommended according to the regs.

BTW I understand a case could be made for AFDD protection for an oven and oven circuit. But for this question I'm just interested in the definition of 'circuits supplying socket outlets' for the purposes of this recommendation.

 

[Dustydazzler]

There are already AFFFDDDS hitting the seconds market at cheap prices

10amp wylex afdd/rcbo Only Installed For Two Weeks then Removed | eBay

10amp wylex affdd/rcbo Only Installed For Two Weeks then Removed.

www.ebay.co.uk

 

[DPG]

There are already AFFFDDDS hitting the seconds market at cheap prices

10amp wylex afdd/rcbo Only Installed For Two Weeks then Removed | eBay

10amp wylex affdd/rcbo Only Installed For Two Weeks then Removed.

www.ebay.co.uk

Makes you wonder why they removed it. Nuisance tripping? Or maybe they have a genuine fault on their installation which will now never be found.

 

[Dustydazzler]

Makes you wonder why they removed it. Nuisance tripping? Or maybe they have a genuine fault on their installation which will now never be found.

Best guess would be nuisance tripping and went back to a normal Mcb

 

[DPG]

Best guess would be nuisance tripping and went back to a normal Mcb

But it could have been detecting a genuine fault on the circuit.

 

[Dustydazzler]

But it could have been detecting a genuine fault on the circuit.

Yes , but customer probably not happy having to keep walking to the consumer unit so sparks changed to an Mcb

 

[DPG]

Yes , but customer probably not happy having to keep walking to the consumer unit so sparks changed to an Mcb

Indeed, and that's the worrying thing.

 

[timhoward]

A little observation - a high percentage of the 2nd hand AFDD's on ebay are Wylex. Coincidence? One to watch at least!

 

[timhoward]

Yes , but customer probably not happy having to keep walking to the consumer unit so sparks changed to an Mcb

and the question is did the 'sparks' check the fault code to see which technology was causing the trip....or just rip it out regardless.

 

[Dustydazzler]

and the question is did the 'sparks' check the fault code to see which technology was causing the trip....or just rip it out regardless.

I have seen 5 or 6 YouTube videos from the States where they literally yank out the AFCI /AFFDDDS if they get a nuisance trip problem and literally replace it with a Mcb

I imagine we will adopt a much similar strategy

 

[DPG]

I have seen 5 or 6 YouTube videos from the States where they literally yank out the AFCI /AFFDDDS if they get a nuisance trip problem and literally replace it with a Mcb

I imagine we will adopt a much similar strategy

Got to be brave to visit an installation with a tripping issue, remove a protective device and then sign your name on the paperwork to say you've done it.

 

[Dustydazzler]

Got to be brave to visit an installation with a tripping issue, remove a protective device and then sign your name on the paperwork to say you've done it.

Who said anything about 'sign'

Cash meet hand see you later

 

[pc1966]

Thing is they are also RCBO so odd tripping might be something simple like N-E fault or borrowed neutral, both easy to detect and fixable without wandering in to the AFDD side of things.

Worrying though to see then removed.

Also a bit odd that is a 10A one, not obvious for what. BIG lighting circuit? Under-provisioned single socket?

 

[DPG]

I definitely think these things are going to catch the cowboy sparks out. Let's face it, some of them won't even notice that it's an AFDD and not just an RCBO.

 

[UNG]

But it could have been detecting a genuine fault on the circuit.

But with the usual test equipment we have can we easily identify the early stages of an arc fault on a circuit and that could be the problem that we have to work with

The Hager AFDD's are reprogrammable via bluetooth so nuisance tripping can be filtered out but how do we know from the information gathered by the Hager data tool and the modified firmware provided by Hager that we are not inadvertantly desensitising the AFDD
The lack of information or any training on AFDD's is woeful and there seems to be a blind faith that they are the be all and end all of electrical safety when there is no external method of testing and confirming the functionality of these devices

 

[Dustydazzler]

But with the usual test equipment we have can we easily identify the early stages of an arc fault on a circuit and that could be the problem that we have to work with

The Hager AFDD's are reprogrammable via bluetooth so nuisance tripping can be filtered out but how do we know from the information gathered by the Hager data tool and the modified firmware provided by Hager that we are not inadvertantly desensitising the AFDD
The lack of information or any training on AFDD's is woeful and there seems to be a blind faith that they are the be all and end all of electrical safety when there is no external method of testing and confirming the functionality of these devices

From what I gather the Americans / Canadians have been using AFCI devices in their homes since around 2012 , but due to nuisance tripping issues limit the use of AFCI to certain rooms only
They had so much nuisance tripping early on they removed their use from Kitchens because certain appliances would repeatedly trip the device even on a brand new install