AFDDs for single-socket circuits

[Markyd]

Would you fit them to all though, not just sockets?

Prob on 10a upwards

 

[mainline]

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.

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.

 

[Selfmade]

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.

 

[ipf]

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.

Some of the tight landlords won’t like paying 50 squid for an EICR and then 300/400 for a small update repair .

 

[pc1966]

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.

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:

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

Beko Fridge Freezer Fire Recall Recall | Electrical Safety First

The Beko Fridge Freezer Fire Recall has been recalled. This product may have safety issues or dangerous defects.

www.electricalsafetyfirst.org.uk

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

 

[pc1966]

Ha that’s a good one! Must be a manufacturers video

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.

 

[UNG]

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.

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

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?

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

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.

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

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.

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

 

[Selfmade]

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.

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.

 

[Selfmade]

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

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?

 

[UNG]

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?

i tink you have really missed the point I was making

 

[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

 

[mainline]

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

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.

 

[westward10]

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.

 

[nicebutdim]

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

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?

 

[DPG]

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?

Probably a fair point. And it avoids the conspiracy theories.

 

[Dartlec]

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?

 

[Markyd]

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

Have a look at the Hagar products...AFDD's with bluetooth capability to upgrade firmware

 

[Dustydazzler]

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?

In America you can actually but a double socket or as they call it a duplex receptacle which has built in AFCI capability.
You are recommended to use the AFCI sockets where white goods appliances , hair dryers , fridge freezers and hoovers etc are to be plugged in...
This way then you don't need AFCI at the board just at the individual socket out-let,

 

[mainline]

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?

There can be a fire risk of some white goods having their power removed whilst part way through a program.

 

[UNG]

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.

This is one of the points I made in an earlier post
What happens if the firmware / software throws a checksum error do they automatically reset as all the AFDD's I've looked at have no indication for it but how often is anyone going to check anyway
When you look at the evolution of the consumer unit years ago convention was to have the higher rated fuses next to the main switch fast forward a decade or three and it is not recommended and you should spread the higher current using circuits across the CU to prevent a build up of heat affecting the RCBO's, AFDD's now are going to add to the heating effect so are we going to need a ventilated CU to reduce the heat build up or a half module gap separating the the circuit devices

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

I mentioned the programmable Hager AFDD's much earlier in this thread but having thought more about it I'm not sure about them, if you have a nuisance trip because an arc signature is detected then how do you evolve the programmed arc signature to eliminate the nuisance trip without missing a real arc fault but we also have the issue of is there an arc fault and how do we verify we haven't before going down the route of reprogramming the AFDD

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

That is anyones guess or is that for the PAT brigade to identify during inspections

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?)

If all the reports from across the pond are to be believed the use of AFCI's is not that widespread with many taken out after installation

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.

As with a lot of stats in some circumstances it is difficult to prove, people will tell you the introduction of Part P saved lives but within 2 years the regs brought in RCD's on everything so what saved the lives, move on and how many lives has the RCD saved we will never know the true number as it trips it is reset and no one logs the fact it tripped or the circumstances why it tripped.
So how will the technology prove itself, the coarse analysis of fire causes will not produce sufficient evidence IMO to prove their worth and what would the price need to come down to make them an automatic fit like we do with RCBO's

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?

And we come back around to cost and safety which is something that is lost on the appliance manufacturers

 

[stewartrossinv]

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.

The analytical team I managed until I retired from the Scottish Fire and Rescue Service were (and are) responsible amongst other things for publishing comparable fire statistics for Scotland.

The stats you kindly quoted are derived from data completed by all fire and rescue services in England, Scotland and Wales on the National Incident Recording System (IRS). The IRS provides some very detailed questions about the source of ignition, item first ignited, fire location, spread of the fire, proportion of the property affected by fire, and so on, but it cannot and does not have the capability of delving into detailed causes that would not be known to the attending crews.

I mention this because knowing that (say) an electrical appliance was the source of ignition tells you very little other than that there was a fire resulting from the use of some form of white goods. The firefighter who records the details on the IRS is recording which item they believe was responsible for the fire and (based on what they found on scene) how it ignited whatever it ignited. The 'which item ignited' can be straightforward when there is a completely destroyed fridge or tumble drier extinguished by the crew sitting in what remains of a kitchen, but the more detailed causal information on why that appliance caught fire is most likely to be ascertained by specialist fire investigators following fatal or major fires. The Beko fridge recall resulted from fire investigation work undertaken (if I remember correctly) by London Fire Brigade, not from analysis of IRS data.

The Beko fridge-freezer fires related to (as I recall) mains spark-suppression capacitors short-circuiting and setting fire to the surrounding casework. I don't know whether or not an AFDD would in any way have stood a chance of detecting the sudden short of the capacitor - the resulting fire started by the shorted capacitor which then spread to the plastic casing is not arc-related at all.

Similarly, the major fires which resulted in the recall of thousands of Whirlpool tumble driers relate to combustion of materials in the drier, not to arcs in its motors or heaters.

The stats quoted are quite correct - but of the 15% of fires the number which may be arc-related is likely to be a small minority. We simply do not know from what is recorded on the IRS, but in the 12 years in which I was involved in this field I can only say that true arc-related fires in Scotland at least were so few that I can't recall any details. That's not to say that AFDDs won't save some lives - only that the Whirlpool fires amongst others would not have been caught by AFDDs, and those dreadful appliance fires have resulted in fatalities.

-Stewart

 

[timhoward]

Thanks @stewartrossinv for adding some helpful context to the debate.