Solution to high cost AFDDs?

[Selfmade]

Hi Folks

Screwfix have Wylex combined AFDD/RCBOs for over £200 each. For a simple hypothetical installation with 2 lighting and two ring final sockets circuits, that's over £800 for devices alone.

So, if one were to install two consumer unit enclosures, one with main switch and two 40A AFDD/RCBOs, each feeding one 32A MCB for a sockets circuit and one 6A MCB for a lighting circuit, in the other enclosure, arranged so that sockets and lights in each room are on different AFDDs, one would in effect have a dual AFDD/RCD consumer unit, something that doesn't (yet?) seem to be available to buy.

Can anyone see any problems with this?

 

[stevethesparks]

When you get an "arc fault" how you going to find it?
Its going to be like finding an rcd/leakage fault with no test gear.

My solution is don't fit them until the manufacturers come up with a much cheaper alternative preferably that take up just one space in the consumers unit.
They also need to introduce some sort of testing equipment, or add-on so we have half a chance of dealing with such faults. (more expense)
At least some sort of port on such a device to plug something into, to enable half a chance of investigation in a fault.

What would be the criteria for recommending these in for a residential system, and how would circuits to be protected be chosen?

Don't get me wrong, arc detection is a great idea that could add more to the safety of a system, but at present it is ill thought out and another knee jerk reaction for an excuse to update the regs once again at our cost.

 

[Pete999]

When you get an "arc fault" how you going to find it?
Its going to be like finding an rcd/leakage fault with no test gear.

My solution is don't fit them until the manufacturers come up with a much cheaper alternative preferably that take up just one space in the consumers unit.
They also need to introduce some sort of testing equipment, or add-on so we have half a chance of dealing with such faults. (more expense)

What would be the criteria for recommending these in for a residential system, and how would circuits to be protected be chosen?

Don't get me wrong, arc detection is a great idea that could add more to the safety of a system, but at present it is ill thought out and another knee jerk reaction for an excuse to update the regs once again at our cost.

Perhaps the new 18th MFT they keep advertising will have this function!! I don't think

 

[stevethesparks]

It will more like it'll be a re-badged 17th edition MFT with added cost.

Call me cynical

 

[stevethesparks]

Racal apollo 2 (security industry year ago) had two pins you could plug an led bar graph onto to see the +/- levels of interference/noise in a room.
This sort of thing would surely be a pretty easy thing to copy by means of a port on each afdd.
It would be a start at least.

 

[stevethesparks]

18th edition 1st amendment:
Items that may cause false triggering that can be fitted with a snubber device along with a risk assessment.

 

[Shoei]

I'd like to see evidence that AFDDs will prevent fires in compliant UK installations before recommending them to a customer. If anyone's seen any please post a link.

AFCIs originated in the US where for various reasons they have a higher incidence of electrical fires due to arcing. In particular, they use higher currents, the UL insulation which prioritises fire resistance is often soft and prone to damage. Timber buildings are more commonplace and American electricians use wire twist connections a lot, with obvious consequences.

In the UK AFDDs look like the latest bandwagon for manufacturers to up sell circuit protection. If we want to improve electrical safety it seems strange that we don't make RCDs mandatory on existing installations. The money can be found to give away low energy bulbs, loft insulation and smart meters, why not a program to provide every domestic user with basic RCD protection?

 

[Pete999]

I don't know if everyone is panicking unnecessarily, after all AFDDs are only a recommendation at present, you can recommend them to clients, but if they balk at forking out £200 plus for one, then don't note that you did recommend their inclusion but they declined due to cost reasons, so in conclusion are folks panicking over nothing?

 

[stevethesparks]

You maybe right......but I do like a good moan

 

[Pete999]

You maybe right......but I do like a good moan

Yeah I thought I did as well, once.

 

[Pete999]

It will more like it'll be a re-badged 17th edition MFT with added cost.

Call me cynical

Yes you're right, Cynicalthesparks.

 

[Toneyz]

Perhaps the new 18th MFT they keep advertising will have this function!! I don't think

I have put a post-it note on my MFT with a big 19 on it does this make it a 19th edition tester?

 

[stevethesparks]

Scenario 1
Me: yes madam, cost of replacement CU £450.00, I can also thoroughly recommend an AFDD at the additional cost of £200 per circuit.
Client: Oh ok, which circuits should I protect?
Me: Oh, you know, the ones that will will be more susceptible to arc problems, fans, cookers, drills (ring finals), showers, it your choice.
Client: you'll be telling me next that I also need to uprate my main protective bonding. On yer bike.

Scenario 2
Me: I could add some AFDD's at £200 each but I wouldn't bother, you don't really need them. I can just put on my paperwork that you declined them - as long as I have informed you that they are available.
Client: You're a cowboy, on yer bike.

I'm done, I'm off to dinner

 

[stevethesparks]

Yes you're right, Cynicalthesparks.

I'll have to change my name, I've never had so much fun

 

[Pete999]

I have put a post-it note on my MFT with a big 19 on it does this make it a 19th edition tester?

Send it away for remodeling as an 18th edition tester

 

[Selfmade]

Wow! What a popular topic! Forgot to say, Happy New Year All!

 

[Selfmade]

When you get an "arc fault" how you going to find it?
Its going to be like finding an rcd/leakage fault with no test gear.

My solution is don't fit them until the manufacturers come up with a much cheaper alternative preferably that take up just one space in the consumers unit.

Insulation resistance might show a parallel arc, maybe higher than expected resistance for a series arc (maybe a bit of guesswork with the second)? Or try switching off one MCB at a time and resetting the AFDD (maybe not much use for an intermittent fault)? Your solution may well be more practical!

 

[Selfmade]

18th edition 1st amendment:
Items that may cause false triggering that can be fitted with a snubber device along with a risk assessment.

Like every single light switch

 

[Selfmade]

Perhaps the new 18th MFT they keep advertising will have this function!! I don't think

Something to help us press the test button and tick a box on the form.

 

[Generator]

There's a more sinister aspect of this AFDD business - they're not mandatory BUT, if a homeowner declines a 'recommendation', what would be an insurance company's response to a future claim following a fire?