AFDDs for single-socket circuits

S

Selfmade

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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.
 
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Selfmade said:
Ahhhh yes but the customer might want them and might be happy to pay for them. Who am I to make a value judgement on their cost/benefit analysis?

Personally if I was doing a CU in my own home I'd probably fit an AFDD for the kitchen sockets but not bother elsewhere.
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You should also point out to the customer that the device will fail at some point, but you don't know when :)
 
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Ha that’s a good one! Must be a manufacturers video

what works are not primarily designed and engineered around cost 🙄

so how much is a CU change going to be now approx?

8-10 type A rcbos, SPD, 12way board with main switch, approx 3 afdds for socket circuits, plus bits and pieces, days labour for fitting and testing, plus allowance for returning to site for further investigation if afdd starts playing up on an appliance that you couldn't detect during testing

must be talking £1000-1200 plus a bit of VAT

thats going to be a hard sell for most electricians I would guess depending on your area in the country

like others have said, I think I will be offering budget, mid-range and premium versions of a consumer unit change
 

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Just now a quick search for the Fusebox brand has RCBO for around £15+VAT and AFDD for around £105+VAT, so around £110 extra parts cost per circuit to the customer (inc VAT), and a bit of margin for returns and call outs for odd trips, so say £150.

Not sure what is typical for a home these days, but it is looking like £300-450 extra if you have 2-3 RFC and if not much else (couple of lights, couple of fixed kitchen appliances), then it is probably adding 50% to a CU change?

Some folk won't have issues with the cost but I bet the majority of customers do! More so when it is a hard sell as to what they really offer in terms of improved safety. We see general fire stats quoted from time to time but so far I have not seen an analysis of what AFDD would have likely stopped versus stuff they would not have detected.

Sure if the were down to £20 versus £15 for RCBO then nobody is going to have a big issue with them, but just now it is going to be a problem for many.
 
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pc1966 said:
More so when it is a hard sell as to what they really offer in terms of improved safety
Click to expand...
There's a certain amount of chicken and egg here, until they end up in more installations we won't see if electrical fire statistics fall in general terms.
What could completely throw the stats is lockdown and the amount of time people spent working at home, and then people returning to workplaces, leading to a rise and fall in domestic fires.

I've had a quick look at some publicly available data:

Percentage of fires, non-fatal casualties and fire-related fatalities in accidental dwelling fires by selected sources of ignition, England; year ending March 2020
1660640070695.png

So electrical-appliance ignition source caused 13% of fires and accounted for 4% of fatalities.
Electrical distribution ignition sources are in fact killing more people.
(Space-heating source fatalities are really quite scary - people plugging in a fan heater in one room and not running the CH is going to be a real issue)

But maybe more relevant is this graph (same year)
Percentage of fires in accidental dwelling, fires by cause of fire, England; year ending March 2020
1660640751021.png

My conclusion for now - If 15% of fires are being caused by faulty appliances then maybe our advice should simply be that AFDDs are an attempt to bring down that number. The reality is that we won't know if it works for several years.

What could help would be some government funded TV adverts, like the original "Wake up - get a smoke alarm" campaign.
 
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timhoward said:
There's a certain amount of chicken and egg here, until they end up in more installations we won't see if electrical fire statistics fall in general terms.
What could completely throw the stats is lockdown and the amount of time people spent working at home, and then people returning to workplaces, leading to a rise and fall in domestic fires.

I've had a quick look at some publicly available data:

Percentage of fires, non-fatal casualties and fire-related fatalities in accidental dwelling fires by selected sources of ignition, England; year ending March 2020
View attachment 100501
So electrical-appliance ignition source caused 13% of fires and accounted for 4% of fatalities.
Electrical distribution ignition sources are in fact killing more people.
(Space-heating source fatalities are really quite scary - people plugging in a fan heater in one room and not running the CH is going to be a real issue)

But maybe more relevant is this graph (same year)
Percentage of fires in accidental dwelling, fires by cause of fire, England; year ending March 2020
View attachment 100502
My conclusion for now - If 15% of fires are being caused by faulty appliances then maybe our advice should simply be that AFDDs are an attempt to bring down that number. The reality is that we won't know if it works for several years.

What could help would be some government funded TV adverts, like the original "Wake up - get a smoke alarm" campaign.
Click to expand...

I wonder what the percentage of that 15% would have been for ones that have had a proper eicr and pat test done.

In my opinion fit AFDD only where required I think they need to be in the wild for a few more years yet, let's wait and find out what the failure rate is first as there most certainly will be.
 
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Fascinating conversation folks!

One quick note about some of the graphs others have shown above - I think when they refer to appliances they are not just referring to electrical appliances. So gas heaters for e.g. would be included.
 
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pc1966 said:
Just now a quick search for the Fusebox brand has RCBO for around £15+VAT and AFDD for around £105+VAT, so around £110 extra parts cost per circuit to the customer (inc VAT), and a bit of margin for returns and call outs for odd trips, so say £150.

Not sure what is typical for a home these days, but it is looking like £300-450 extra if you have 2-3 RFC and if not much else (couple of lights, couple of fixed kitchen appliances), then it is probably adding 50% to a CU change?

Some folk won't have issues with the cost but I bet the majority of customers do! More so when it is a hard sell as to what they really offer in terms of improved safety. We see general fire stats quoted from time to time but so far I have not seen an analysis of what AFDD would have likely stopped versus stuff they would not have detected.

Sure if the were down to £20 versus £15 for RCBO then nobody is going to have a big issue with them, but just now it is going to be a problem for many.
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Some of the tight landlords won’t like paying 50 squid for an EICR and then 300/400 for a small update repair .😉
 
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timhoward said:
So electrical-appliance ignition source caused 13% of fires and accounted for 4% of fatalities.
Electrical distribution ignition sources are in fact killing more people.
Click to expand...
Thanks for looking up those stats.

However, they do not identify the details of it. If it were an arcing break then AFDD would have a good chance of reducing the fires and thus fatalities, however, most of the faulty appliance recalls I remember have been stuff like tumble dryers clogging with lint and catching fire, or fridge-freezers, etc, and they are not going to be helped by AFDD as by time it fails to the arcing point it is well underway as a blaze! A quick search pulled up these:

www.theguardian.com

Which? names 250 fridges and freezers that pose fire risk

Consumer group tells retailers to stop selling models using ‘unsafe’ plastic backing material
www.theguardian.com www.theguardian.com

https://www.-----------------------.../08/reminder-beko-fridge-freezer-fire-recall/

Total Recalls: How to check if your tumble dryer is a safety risk

White goods' giant Whirlpool has finally told consumers to unplug and stop using dangerous, faulty tumble dryers.
www.london-fire.gov.uk www.london-fire.gov.uk
 
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Welchyboy1 said:
Ha that’s a good one! Must be a manufacturers video
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That image you show saying "cost should not be the major factor" is really condescending and misses the point completely. If we were talking something like £5 extra for AFDD then it might be reasonable, but if it is potentially the difference between £400 and £800 for a CU change (adjusted for your area's affluence) then it is going to make a lot of people thing twice and either not do it, or go to some Dodgy Dave character who offers it for 1/3 the price and makes a complete hash of it.

That is the reality, are you trying to make a few installations a fraction of a percent safer but at the cost of many other being left unsafe or even made more dangerous?

While folks on this forum debate the choices of CU brand and design aspects like dual RCD versus RCBO, the reality is any of you could install any cheap CU and make an old or damaged installation far safer than ignoring it or leaving it to some untrained incompetent.

At least for now for most homes AFDD are options so offering budget and best-case can cover a range of client's ability to pay.
 
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pc1966 said:
That image you show saying "cost should not be the major factor" is really condescending and misses the point completely. If we were talking something like £5 extra for AFDD then it might be reasonable, but if it is potentially the difference between £400 and £800 for a CU change (adjusted for your area's affluence) then it is going to make a lot of people thing twice and either not do it, or go to some Dodgy Dave character who offers it for 1/3 the price and makes a complete hash of it.
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Unfortunately it is easy to say "cost should not be a major factor" but for some who are watching the pennies "significant cost is the major factor" in their budgeting for improvements to their property
pc1966 said:
That is the reality, are you trying to make a few installations a fraction of a percent safer but at the cost of many other being left unsafe or even made more dangerous?
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MCB's and RCD'S / RCBO's have over a number of years developed a track record for majorly improving safety. With RCD's / RCBO's it is difficult to quantify the improvement because no one reports or tracks why or when they trip. So moving onto AFDD's who has found, analysed and reported the faults where an AFDD "may" offer a significant safety improvement to an installation
pc1966 said:
While folks on this forum debate the choices of CU brand and design aspects like dual RCD versus RCBO, the reality is any of you could install any cheap CU and make an old or damaged installation far safer than ignoring it or leaving it to some untrained incompetent.
Click to expand...
I have picked you quite a few jobs recently because I will do exactly that, mainly for older people who want a safer installation but don't want the trauma of major renovation work, I'm sure there are a lot who will call me out but while it is not to the letter of the regs it gives the homeowner some piece of mind that they will get a better indication that they have a fault
pc1966 said:
At least for now for most homes AFDD are options so offering budget and best-case can cover a range of client's ability to pay.
Click to expand...
The problem is the "must" and "mandatory" group who force the issue without any hard facts or fault analysis to back up the safety value they offer

How long before we see real world figures that show that SPD's are actually doing their job, offering protection from a lightning strike is a bit of an unknown when you look at the strike risk for an area which depends a lot on the figures you use for the calc. A hospital I used to do a lot of work 20 - 25 years ago at took a strike one Sunday morning causing £450K - £500K of damage one of the hospital engineers was subsequently tasked with doing a risk assessment on future risk of a a strike the outcome of which was they could have a lightning strike once every 42 days or once every 4 years or once every 40 years or once every 400 years depending what factors were applied in the calculation, the cost estimate for the necessary surge protection was £500K - £600K given the most of the buildings were part of a workhouse dating back some 300 - 400 years and there were no records of a strike in the previous 50 - 60 years the decision was to not bother putting the protection in. So were are the historical figures to compare to the theoretical figures to actually assess the risk of needing an SPD on an installation and IMO the same goes for the AFDD how many faults have any of us out on the ground seen where an AFDD "may" have detected the fault an earlier stage than the existing protection devices
 
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pc1966 said:
That image you show saying "cost should not be the major factor" is really condescending and misses the point completely. If we were talking something like £5 extra for AFDD then it might be reasonable, but if it is potentially the difference between £400 and £800 for a CU change (adjusted for your area's affluence) then it is going to make a lot of people thing twice and either not do it, or go to some Dodgy Dave character who offers it for 1/3 the price and makes a complete hash of it.

That is the reality, are you trying to make a few installations a fraction of a percent safer but at the cost of many other being left unsafe or even made more dangerous?

While folks on this forum debate the choices of CU brand and design aspects like dual RCD versus RCBO, the reality is any of you could install any cheap CU and make an old or damaged installation far safer than ignoring it or leaving it to some untrained incompetent.

At least for now for most homes AFDD are options so offering budget and best-case can cover a range of client's ability to pay.
Click to expand...
Some good points, but it's not just ability to pay, it's also individual choice and priorities. Concepts that are lost on too many in this age we live in.
 
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UNG said:
How long before we see real world figures that show that SPD's are actually doing their job, offering protection from a lightning strike is a bit of an unknown when you look at the strike risk for an area which depends a lot on the figures you use for the calc. A hospital I used to do a lot of work 20 - 25 years ago at took a strike one Sunday morning causing £450K - £500K of damage one of the hospital engineers was subsequently tasked with doing a risk assessment on future risk of a a strike the outcome of which was they could have a lightning strike once every 42 days or once every 4 years or once every 40 years or once every 400 years depending what factors were applied in the calculation, the cost estimate for the necessary surge protection was £500K - £600K given the most of the buildings were part of a workhouse dating back some 300 - 400 years and there were no records of a strike in the previous 50 - 60 years the decision was to not bother putting the protection in. So were are the historical figures to compare to the theoretical figures to actually assess the risk of needing an SPD on an installation and IMO the same goes for the AFDD how many faults have any of us out on the ground seen where an AFDD "may" have detected the fault an earlier stage than the existing protection devices
Click to expand...
So it's anyone's guess. In domestic where I work, people will weigh up all sorts of factors besides the economic - peace of mind vs. potential distress, sentimental value of the equipment that might be damaged, their own personal level of risk aversion etc. etc. And why shouldn't they?
 
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Selfmade said:
So it's anyone's guess. In domestic where I work, people will weigh up all sorts of factors besides the economic - peace of mind vs. potential distress, sentimental value of the equipment that might be damaged, their own personal level of risk aversion etc. etc. And why shouldn't they?
Click to expand...

i tink you have really missed the point I was making
 
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timhoward said:
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.
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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
 
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Dustydazzler said:
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
Click to expand...

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.
 
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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?
 
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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.
 
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DPG said:
But it could have been detecting a genuine fault on the circuit.
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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
 
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UNG said:
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
Click to expand...
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
 
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UNG said:
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
Click to expand...
For that price, they shouldn't have to be played with at all or have the means to be.

I can see smart consumer units being the next thing, why does the can of worms come to mind.
 
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I stand to be corrected but I believe @Megawatt our US correspondent said they fit them and then once it has been inspected they are often ditched for other devices.
 
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timhoward said:
A little observation - a high percentage of the 2nd hand AFDD's on ebay are Wylex. Coincidence? One to watch at least!
Click to expand...

Ebay has long been a steady source of supply for new Crabtree & Wylex RCBOs, with AFDDs slowly creeping in. My suspicion has long been that many make their way there from over-ordering on jobs, rather than being returned to employers., but some sellers seem to have significant supplies. Who knows?
 
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nicebutdim said:
Ebay has long been a steady source of supply for new Crabtree & Wylex RCBOs, with AFDDs slowly creeping in. My suspicion has long been that many make their way there from over-ordering on jobs, rather than being returned to employers., but some sellers seem to have significant supplies. Who knows?
Click to expand...

Probably a fair point. And it avoids the conspiracy theories.
 
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One issue I am concerned about with AFDDs is that they are effectively small computers.

That means firmware/software and with that comes issues of maintenance/errors/life expectancy due to heat/electronics.

What happens when/if they develop a new and improved version? Will there be a way to update existing units (I suspect not).

What will happen if a new appliance is released that just by coincidence produces a similar 'fingerprint' to the one looked for?

I know the idea is not new, particularly in the US, but I believe that our ones are rather different and therefore still fairly new and untested in wide usage (Are they widely used in other part of the 230V world?)

I doubt I will be fitting them anywhere other than I have to for some time to come, until the technology has proved its usefulness and the price has dropped significantly.

Surely if the belief is that a lot of the problems this will solve are within appliances, the better solution would be to include some sort of AFDD within every appliance. Wonder why the appliance makers and large companies who sit on the regs committee didn't consider that? 🤨
 
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