AFDD in 18th 2nd Amendment

[John-SJW]

It’s a big book of regulations.

If I everything was “you must do this”, “you must do that”, “ you must not do the other” then it would be even more boring than it is now reading it cover to cover

It is not a novel to read while in bed.

 

[davesparks]

“Shall” and “must” mean the same thing… you could interchange those two words in any of the regs and it would mean the same.

They aren't as interchangeable as you would think, swapping shall for must in the regulations would make them grammatically incorrect and potentially change their meaning.

 

[littlespark]

They aren't as interchangeable as you would think, swapping shall for must in the regulations would make them grammatically incorrect and potentially change their meaning.

If its grammatically incorrect, then it wouldnt be in the regs at all.

What i meant was that as long as the sentence still made sense, then shall and must can be swapped.

I wouldn't say one is as "serious" as the other... even the ten commandments used "Shall" (which could be down to translation, of course)


I think ill just sit and watch some more python videos

 

[JBW175]

If its grammatically incorrect, then it wouldnt be in the regs at all.

What i meant was that as long as the sentence still made sense, then shall and must can be swapped.

I wouldn't say one is as "serious" as the other... even the ten commandments used "Shall" (which could be down to translation, of course)


I think ill just sit and watch some more python videos

We had an eleventh commandment when I was at school. It belonged to my physics teacher Mr Shaw; he was a mean aim with a board rubber.

“Right boys, you all know the 10 commandments, we’ll here’s the 11th, Shaws’ rule; Thou shall not prat about!”

The old bugger wasn’t one for nonsense.

 

[littlespark]

Tangent!

Our science teacher was a hippy Liverpudlian…. And everybody he disagreed with was a “great steaming wassack!”

 

[mainline]

Just did a bit of digging as I know there have been changes to these boards over the years, but can not find anything which confirms if aluminium was ever used for the enclosure. I know they used to be (probably still are) cast, rather than pressed, which might account for the odd feel it had when drilling.

Try a search for the CFGAR1-BD

 

[mainline]

Try a search for the CFGAR1-BD

Not listed on the Bg site as far as I can see, but lots of other Sites, all saying aluminium.

If this is indeed the case, it should put an end to the debate of whether steel is effectively the only permissible material.

 

[nicebutdim]

Not listed on the Bg site as far as I can see, but lots of other Sites, all saying aluminium.

If this is indeed the case, it should put an end to the debate of whether steel is effectively the only permissible material.

It may not put an end to the debate as it's now an obsolete part number.

I wonder exactly when it became obsolete - prior to, or after, introduction of requirement for non- combustible material?

 

[mainline]

It may not put an end to the debate as it's now an obsolete part number.

I wonder exactly when it became obsolete - prior to, or after, introduction of requirement for non- combustible material?

Still available though and 18th compliant.

 

[nicebutdim]

Still available though and 18th compliant.

That would seem to settle the issue.

 

[John-SJW]

A point brought up in this thread was that expensive AFDDs being mandatory in flats in blocks of 6 floors and over, installation will be cut to the bare bone to save costs, with 1940s/50s levels of scant circuits. They may filter down to all residential installations. But it can be done safely and cheaply...

So let's look at a 3 bed flat on the 6th floor.
1. One final ring with a 32A AFDD. This has no heavy current appliances apart from say a 3kW kettle. Most being TVs and the likes.
2. RCBOs on all other circuits.
3. LED lighting, smoke alarm and bathroom extractor fan has one circuit using 1.00mm cable. 3A RCBO.
4. Heavy kitchen appliances on one circuit. A 4mm cable to a bank of FCUs in the kitchen. 1.5mm cable from FCU to each appliance: w/machine, tumble dryer, dish washer. Appliances hard wired in - safer. 40A RCBO.
5. 6mm cooker cable to the oven and induction hob - no need to be on separate circuits. Both hard wired in. 40A RCBO.

So, four circuits. One AFDD and three RCBOs. 1.00mm and 1.5mm cable used. Cheap and safe.

The same could be for an average British semi. Maybe with two lighting circuits - but two are not required. This gives five circuits. Installation costs are then cut right down.

 

[nicebutdim]

I don't see an argument in favour of such distribution. It's likely that some sparks will take that sort of approach, but I'd expect most would follow a combination of logic, regulatory guidance and sound engineering judgment to limit the possibility of overloading and nuisance tripping.

Given the potential leakage from dish washers, washing machines and fridge freezers, not to mention a plethora of other appliances likely to make their way into modern homes, I'd question the ability of anyone designing such an installation.

 

[John-SJW]

I don't see an argument in favour of such distribution. It's likely that some sparks will take that sort of approach, but I'd expect most would follow a combination of logic, regulatory guidance and sound engineering judgment to limit the possibility of overloading and nuisance tripping.

Given the potential leakage from dish washers, washing machines and fridge freezers, not to mention a plethora of other appliances likely to make their way into modern homes, I'd question the ability of anyone designing such an installation.

Nuisance tripping? Where? How?
Overloading? Where?

Q1? Is it safe? Yes.
Q2? Is it legal? Yes.
Q3? Does it protect against arcing on sockets? Yes.
Q4? Does it give full RCD protection? Yes.
Q5? Does full overload protection? Yes.
Q5? Does it give full fault protection? Yes.

You may not see an argument for it, and more will be on your side because of: we have always done it this way. My point is that as AFDDs are expensive and mandatory with copper cable prices rising as world copper prices rise, these sorts of installations may be coming soon, and be quite common.

As a side issue, the British are famous for over-sizing cable. 6mm to a hob when 4mm will do it. 1.5mm for lighting when 1.00mm can do it, 2.5 from an FCU to an appliance when 1.5mm can do it, etc.

 

[nicebutdim]

Nuisance tripping? Where? How?

Q1? Is it safe? Yes.
Q2? Is it legal? Yes.
Q3? Does it protect against arcing? Yes.

You may not see an argument for it, and more will be on your side because of: we have alwasy done it this way. My point is that as AFDDs are expensive and mandatory with copper cable prices rising as world copper prices rise, these sorts of installations may be coming soon, and be quite common.

As a side issue, the British are famous for over-sizing cable. 6mm to a hob when 4mm will do it. 1.5mm for lighting when 1.00mm can do it, 2.5 from an FCU to an appliance when 1.5mm can do it, etc.

It's not a case of 'we've always done it this way' - quite the opposite, in fact, and I don't consider the questions you're applying to such design to be sufficient to ensure a problem free installation for the modern home.

There may, of course, be a significant difference between the approachs one takes for a new build or re-wire, depending on circumstances for the latter.

 

[John-SJW]

ensure a problem free installation for the modern home.

Tell me where that installation would give problems? All heavy appliance are on their own radial. As are the cooking appliances - a 3kW oven or hob with 13A plugs are not on the ring. The ring will take few heavy current appliances and these used only for very short periods. The installation will be sound indeed with high protection.

I think you may be on about devices that operate on earth leakage.