Again the dreaded 18th edition additions...AFDDs

[michaelw6]

Ive search the forums and cannot find a conclusive answer.
I have been reading my New Regs Book today (Thank you sam400) and the IET BSI changes within BS7671:2018.
Now it says 'chapter 42 protection against thermal effects:- New regulation 421.1.7 recommending installation of arc fault devices. now when you read this regulation is says as above. The AFDD shall be placed at the origin of the circuit to be protected. Example: Premises with sleeping accommodation.
Now that to me would be a domestic dwelling, yet when i ring wholesalers i just get the reply 'Nobodys fitting them! We have no call for them! or Waiting to hear back from supplier!'
Now when it comes to SPD devices they are being pre fitted into consumer units now, even with type A RCDs.(Hager)
Id like to install Schneider but they dont seem to do anything 18th yet.
My Question is Regs say they need to be fitted. Can you get a main one to cover all or should i just fit them to the lighting and sockets where the bedrooms are? or every circuit?
Not fitted any AFDD's myself yet so what do you guys do and what manufacturers do you use?

 

[Dustydazzler]

Arc fault circuit breakers are a cash cow

 

[Ian1981]

Ive search the forums and cannot find a conclusive answer.
I have been reading my New Regs Book today (Thank you sam400) and the IET BSI changes within BS7671:2018.
Now it says 'chapter 42 protection against thermal effects:- New regulation 421.1.7 recommending installation of arc fault devices. now when you read this regulation is says as above. The AFDD shall be placed at the origin of the circuit to be protected. Example: Premises with sleeping accommodation.
Now that to me would be a domestic dwelling, yet when i ring wholesalers i just get the reply 'Nobodys fitting them! We have no call for them! or Waiting to hear back from supplier!'
Now when it comes to SPD devices they are being pre fitted into consumer units now, even with type A RCDs.(Hager)
Id like to install Schneider but they dont seem to do anything 18th yet.
My Question is Regs say they need to be fitted. Can you get a main one to cover all or should i just fit them to the lighting and sockets where the bedrooms are? or every circuit?
Not fitted any AFDD's myself yet so what do you guys do and what manufacturers do you use?

The regulations do not say they must be installed, they are only a recommendation,but if installed then they shall be installed at the origin of the circuit that is to be protected, add that to the cost of the product is why nobody is installing them.
I would add that the term sleeping accommodation refers to hotels,HMO’s and the like rather than a domestic dwelling as bs7671 references the term ‘dwellings’ as your typical domestic house

 

[Midwest]

You’d think that someone who can publish a technical document, would also have a reasonable grasp of the English language to phrase descriptions or definitions, so as not to cause a misunderstanding or confusion. Or is that too much of a big ask

 

[Wilko]

How hard would be to add a few things into the definitions? Sorry, thats a self answering question as it's clearly tooo hard for IET.

 

[Spoon]

Welcome to the forum @SparkyNinja.

 

[Spoon]

As above, they are a 'recommendation'.
You could give the customer 2 options. One with AFDD's and one without. The one with, stating the advantages of having AFDD's.
Then it is up to the customer to decide.

 

[Spoon]

We had a post about these and John Ward testing them, where he did a rubbish test.
When looking into the details of AFDD's it looks like the current had to be over 2.5A when detecting.
Not sure how what will work out for lighting circuits in modern houses that have all LED lights.

 

[Dustydazzler]

Having spoken to afew electrical engineers about the concept of arc fault circuit interruption, they were all very sceptical about the functionality of these devices.
From what I gather arc fault breakers were introduced into the Nec code due to the amount of extension lead shorts and overload burn outs in America and Canada.
Their leads and plugtops are much more flimsy than ours.

 

[ackbarthestar]

Having spoken to afew electrical engineers about the concept of arc fault circuit interruption, they were all very sceptical about the functionality of these devices.
From what I gather arc fault breakers were introduced into the Nec code due to the amount of extension lead shorts and overload burn outs in America and Canada.
Their leads and plugtops are much more flimsy than ours.

The American electrical supply is 115V single phase with a correspending higher current for the equivalent appliance power rating, so its no surprise that there is a greater chance of the need for a method of arc detection.

I think that once the manufacturers have got to grips with the risks involved in this country where the likelihood is actually quite small compared to other factors then the designs of protective devices may have combined functionality such as RCBO with SPD and AFDD. Until then the regs only recommend the use which stands for very little.

 

[Midwest]

^^^^
You were saying?