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Most clients will not have a clue what you are even talking about, and I can see the answers you would be getting, why ask me your the professional, how much, your just trying to rip me off.
Saw the 6amp module on test (youtube) it was rubbish didn't even trip, only on a high load current above 6amps, which kinda defeats the object.
 
Not being funny, but if these AFDD's were cheaper, it wouldn't be up for discussion. After all, everyone is fitting SP's. The only surge damage I've ever seen, is when lightning struck next doors house.
 
Why are they not needed?
The regs say:

421.1.7 Arc fault detection devices conforming to BS EN 62606 are recommended as a means of providing additional protection against fire caused by arc faults in AC final circuits.

If used, an AFDD shall be placed at the origin of the circuit to be protected. NOTE: Examples of where such devices can be used include:
• premises with sleeping accommodation
• locations with a risk of fire due to the nature of processed or stored materials, i.e. BE2 locations (e.g. barns woodworking shops, stores of combustible materials)
• locations with combustible constructional materials, i.e. CA2 locations (e.g. wooden buildings)
• fire propagating structures, i.e. CB2 locations
• locations with endangering of irreplaceable goods. "


Don't houses have "Sleeping accommodations"?

This was discussed a few years ago in this thread.
 
Why are they not needed?
The regs say:

421.1.7 Arc fault detection devices conforming to BS EN 62606 are recommended as a means of providing additional protection against fire caused by arc faults in AC final circuits.

If used, an AFDD shall be placed at the origin of the circuit to be protected. NOTE: Examples of where such devices can be used include:
• premises with sleeping accommodation
• locations with a risk of fire due to the nature of processed or stored materials, i.e. BE2 locations (e.g. barns woodworking shops, stores of combustible materials)
• locations with combustible constructional materials, i.e. CA2 locations (e.g. wooden buildings)
• fire propagating structures, i.e. CB2 locations
• locations with endangering of irreplaceable goods. "


Don't houses have "Sleeping accommodations"?

This was discussed a few years ago in this thread.
It’s not accommodation tho for domestic in the sense of say accommodation like a hotel.
The regulations use the word dwellings for domestic so I don’t think that the word accommodation applies, plus it’s a recommendation only and not a full blown requirement to install them.
 
It’s not accommodation tho for domestic in the sense of say accommodation like a hotel.
The regulations use the word dwellings for domestic so I don’t think that the word accommodation applies

Just checked the regs. "Accommodation" is used 12 times and you are correct, it doesn't apply to houses. It does apply to caravans, leisure vehicles, mobile homes & motor caravans.

plus it’s a recommendation only and not a full blown requirement to install them.

We live in a 'blame' society. When you are up in court and they tell you the regs 'recommend' you to use them, you have to prove you have done so.
 
Just checked the regs. "Accommodation" is used 12 times and you are correct, it doesn't apply to houses. It does apply to caravans, leisure vehicles, mobile homes & motor caravans.



We live in a 'blame' society. When you are up in court and they tell you the regs 'recommend' you to use them, you have to prove you have done so.
Just checked the regs. "Accommodation" is used 12 times and you are correct, it doesn't apply to houses. It does apply to caravans, leisure vehicles, mobile homes & motor caravans.



We live in a 'blame' society. When you are up in court and they tell you the regs 'recommend' you to use them, you have to prove you have done so.
The regulations are only recommending that the designer select AFDD’s not that the client does, as a means of fire protection, as the designer they are other means to skin a cat so no I do not feel that you will have to prove anything.
They do not have to be installed at all for compliance with bs7671 so cannot be used against anyone in a court of law against a non statutory document.

As a side note I’d definitely consider installing them if DB’s and CU’s could actually have the capacity to install them and that the price was not ridiculous.
Also the fact that most are 2 module and that’s not including an rcbo into the mix.
They remain a non starter for me and I do not recommend them to a client as they are my choice whether to install or not.
 
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Just now they will add something like £1k to the cost of a CU change, and only a few AFDD are single-width modules (e.g. Wylex/Crabtree brand AFDD/RCBO units), so you have that extra size to deal with. And all of this for a marginal gain in safety.

In most cases the client would be better spending the extra money on a fire alarm and/or some extinguishers!
 
Just now they will add something like £1k to the cost of a CU change, and only a few AFDD are single-width modules (e.g. Wylex/Crabtree brand AFDD/RCBO units), so you have that extra size to deal with. And all of this for a marginal gain in safety.

In most cases the client would be better spending the extra money on a fire alarm and/or some extinguishers!
Or on a SPD that they might not need :rolleyes:
 
If an RCD trips we have test equipment to enable us to decide whether there is a wiring fault, a connected equipment fault or it's a faulty RCD
So an AFDD trips how do we identify the cause, I had quite a long chat with one of the Megger guy's at Elex a couple of years back as the AFDD was starting to appear on the horizon, he was saying that identifying the cause would be a decision to rewire the circuit, replace the AFDD or potentially doing both all of which has a high cost for the customer. Then there is the question of the AFDD test button and how reliable it is look how often the RCD test button works but fails when tested with a meter. The case for AFDD's seems driven by the manufacturers who seem to have total belief that their AFDD's are capable of identifying all arc fault situations that could possibly occur yet there is no test equipment available that allows the electrician on the ground to prove that an AFDD protected circuit will be disconnected if an arc fault occurs

Currently I can demonstrate to a customer why their RCD or a connected circuit or a piece of connected equipment is faulty, How do or can I go to a customers premises with a tripping AFDD and not be able to do any tests and suggest a repair that has the potential to cost anything from a few hundred to a few thousand pounds after the AFDD and the wiring has been swapped because I don't have any equipment to identify the exact cause of the problem

It's a bit liking taking your car for a repair only to be told it needs a couple of ECU's when real fault is a damaged connector
 
Then there is the question of the AFDD test button and how reliable it is look how often the RCD test button works but fails when tested with a meter.
This!

As you say there it is putting great faith in the AFDD self-test capabilities and without any 3rd party diagnostics you are in the position of not knowing if the AFDD is flaky or there really is a sparking connection somewhere.
 
The crabtree combined AFDD's give an LED indication of which element of the device has caused it to operate
 
Have a look at this thread. I have thought about it for a long time and tend to think @Cookie and @Sisyphus (who may disavow the below!) are correct. Effectively AFDD are fraudulent and manufactured by the people who make the regs. Go figure!
AFDDs are a massive fraud - https://www.electriciansforums.net/threads/afdds-are-a-massive-fraud.175536/#post-1553501 it is a long thread and I think there was another one. What is being said is that RCD do the job of AFDD in essence (gross simplification). We are being foisted with items that are not needed and very little science to show they are. We and the public are paying hand over fist for profit for the big boys, if we don't sign up to this fraud we are out of the scheme.

It is a difficult one. I say the above as if you look at the thread and links there are very convincing arguments this really is the case. I recall Wago wanted in on the European market. Hager, who are on JPEL who write the regs, brought in the requirement for the MF mark, which stopped Wago getting in on the market as their application for MF mark was massively delayed. I have no doubt there are many other instances of this type of practice.
We need an engineering committee with no such conflict of interests to write the regs from a purely science/practice viewpoint.
Good read. There has been a certain whiff in the air regarding AFDD, s which has not been pleasant to the nostrils. The manner they have been "marketed" has, nt helped. Now in time as you say we may be provided with a bit more background supporting the reasons for their introduction. But for now I think in many sparks mind, the jury is still out on them.
I have never had direct experience of an electrical fire. The cases I have heard of were either down to overloading at the DB (rare) or caused by appliances (most common) I have never heard for instance of a case involving arcing in the fixed wiring of an installation
 
Good read. There has been a certain whiff in the air regarding AFDD, s which has not been pleasant to the nostrils. The manner they have been "marketed" has, nt helped. Now in time as you say we may be provided with a bit more background supporting the reasons for their introduction. But for now I think in many sparks mind, the jury is still out on them.
I have never had direct experience of an electrical fire. The cases I have heard of were either down to overloading at the DB (rare) or caused by appliances (most common) I have never heard for instance of a case involving arcing in the fixed wiring of an installation

There are definitely other cause, including loose connections. A colleague of mine attended a consumer unit last week which had overheated and caused smoke damage and charring. Suspected loose connection at bus bar or main switch which had become worse over time.
 
If the regulations change then so will the advise given to clients. But at the present time nobody is going to be pursued for not fitting AFDD's, even if the place burns down assuming the current requirements of Bs7671 have been met.
My point wasn't about the advice that we give - it was about acceptance of the technology. If we keep ignoring it playing the current card, we'll find down the road that we'll have to adapt them anyway.
 
They will come down in price eventually to the point they are comparable to today's RCBOs and probably future MFTs will have some test capability for that (assuming the AFDD manufacturers agree to a common sensitivity profile, etc, allowing 3rd party testing).

But for now they are a lot of money for a marginal benefit.

I may be wrong, but it would then be nice to see some impartial analysis of the percentage of fires that would be stopped by AFDD to see what the real gains are.
 
My point wasn't about the advice that we give - it was about acceptance of the technology. If we keep ignoring it playing the current card, we'll find down the road that we'll have to adapt them anyway.
The problem is having the tools to verify the technology and being able to identify an AFDD fault or an in circuit fault, we are currently being blindly pushed into AFDD use to protect against something similar to a lightning strike and in the recent weather how many domestic properties have been struck by lightning.

Having to adapt to them sounds like we will be forced into blindly accepting the technology, the problem of acceptance will only be solved when better and more informed information put out into the industry domain

How do you explain to a customer that a CU swap is now going to cost around £2 - 2.5k because they may or just might get a "lightning strike" in one of their circuits. You do a rewire you fit AFDD's to protect against that possible "lightning strike" what does that say to the customer about the quality of your workmanship when one result from a google AFDD search will give you

Arc Fault Detection - Hager UK

Extract from Arc Fault Detection - Hager UK said:
Potential Causes

Arc faults can be caused by all types of line faults and worn contacts;
  • Kink / break in a cable
  • Cable wear due to frequent use
  • Cable damage resulting from drilling or construction work
  • Incorrect wire stripping
  • Incorrect bending radii
  • Loose screwed connections
  • Defective wall plugs
  • Rodents biting cables
An AFDD will trip the circuit when a potentially hazardous arc occurs, eliminating the resulting fire hazard.

If AFDD use becomes mandatory there is the potential that basic electrical safety upgrades will not happen as the cost may be too high for people to accept
 
If AFDD use becomes mandatory there is the potential that basic electrical safety upgrades will not happen as the cost may be too high for people to accept
Exactly, that would lead to far more risk!

I doubt they will become mandatory for some time, not least until costs come down and some sort of 3rd party testing becomes practical.
 
There are definitely other cause, including loose connections. A colleague of mine attended a consumer unit last week which had overheated and caused smoke damage and charring. Suspected loose connection at bus bar or main switch which had become worse over time.
There are definitely other cause, including loose connections. A colleague of mine attended a consumer unit last week which had overheated and caused smoke damage and charring. Suspected loose connection at bus bar or main switch which had become worse over time.
Agreed. When I used "overloading" in my post, I should have said overheating. All the cases I am aware of were caused by overheating due to high resistance points resulting from either loose connections or worn switches etc
 
They will come down in price eventually to the point they are comparable to today's RCBOs and probably future MFTs will have some test capability for that (assuming the AFDD manufacturers agree to a common sensitivity profile, etc, allowing 3rd party testing).

But for now they are a lot of money for a marginal benefit.

I may be wrong, but it would then be nice to see some impartial analysis of the percentage of fires that would be stopped by AFDD to see what the real gains are.
Far from been wrong, I think you have hit the nail right on the head. Impartial analysis would highlight to what degree is this an actual issue.? Who of us would, nt agree to enhanced protective measures.?
 

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