4mm radial circuit

[Guest55]

at the end of the day you can talk about the finer points of reference methods and ccc till the cows come home.
but 4mm under floors on a 32mcb works just fine , end of.
you either see that through experience or you get hung up on the regs because you lack said experience.
im happy to rely on my own engineering judgements that come with 20 years in the game , many others dont.

 

[Heisenberg]

at the end of the day you can talk about the finer points of reference methods and ccc till the cows come home.
but 4mm under floors on a 32mcb works just fine , end of.
you either see that through experience or you get hung up on the regs because you lack said experience.
im happy to rely on my own engineering judgements that come with 20 years in the game , many others dont.

The trouble is, a lot of you old timers want to have your cake and eat it. Anyone who comes on here and says something that is against the regs, generally but not always, gets blasted and labelled a Electrical Trainee. Yet, when the forum Illuminati do it, we're just told to accept it as 'experience'.

At the end of the day, to coin your phrase, sticking to the regs never got anyone killed, so I find it strange that people would get criticised for doing so.

Cheers

 

[Sparkytlec]

Perhaps if you disregarded BS 7671 when it comes to CCC of cables, and use the manufacturers data, you may find that your worries are totally unfounded!!

Why do you and it seems many others, need every situation documented in BS7671 (or by other bodies), it's never going to happen!! BS7671 is basically only a guide at the end of the day, your still expected to make your own educated decisions based on your electrical knowledge etc!!

I actually agree with your statement as you could wire a house in two bits of wet string if it worked. However in this day and age of litigation it only takes the slightest thing to happen and someone gets hurt, (it may not be even anything to do with the circuit you have wired) then there is an investigation and the HSE say prove your work is safe and there are only two ways to do that one is to have proven manufactures test data or to have abided with current BS7671. When you can't prove that say sorry but that's not good enough. At best it's a heavy fine at worst it's a prison sentence and yes that can and dose happen!

There fore I'm not willing to risk it.

 

[Richard Burns]

This is all assuming that 'under the floorboards' is method B.

What does 1.5De ≤ V < 50De mean?

where De is diameter of cable and V is height of space.

I can understand one side or the other but together it doesn't seem to make sense.

If say the cable is 4 mm2 flex of diameter 11.6 mm
the minimum dimension of the space must be greater than 1.5 x 11.6 mm = 17.4 mm
the minimum dimension of the space must be less than than 50 x 11.6 mm = 580 mm
Outside of these values the installation method does not apply.
Since most spaces between floor boards are greater than 17 mm and less than 580 mm it probably does apply in this case.

 

[Guest55]

The trouble is, a lot of you old timers want to have your cake and eat it. Anyone who comes on here and says something that is against the regs, generally but not always, gets blasted and labelled a Electrical Trainee. Yet, when the forum Illuminati do it, we're just told to accept it as 'experience'.

At the end of the day, to coin your phrase, sticking to the regs never got anyone killed, so I find it strange that people would get criticised for doing so.

Cheers

i've never said any of things so you must be mistaking me for someone else.
if fact im happy to admit to bending guidelines when i know an install will work perfectly fine.
i care not if others do also , thats their business.

and i'm only 41.
;-)

 

[Geoffsd]

Thank you.

Yes that was my thinking about the formula

so, method B applies because of being less than 50 x 11.6 (580mm)

Considering B applies to conduit as well, that's a hell of a space before method C could be used.

When is 1.5 x 11.6 (17.4mm) ever going to be needed and what happens if it's 17.3 ?

 

[trev]

and i'm only 41.
;-)

Take a seat over there with the rest of us dinosaurs mate

 

[Guest55]

Take a seat over there with the rest of us dinosaurs mate

put a sock in it grandad , im still cool and hip.
;-)

 

[trev]

So am I, it's only me kids that say I'm not

 

[Engineer54]

I actually agree with your statement as you could wire a house in two bits of wet string if it worked. However in this day and age of litigation it only takes the slightest thing to happen and someone gets hurt, (it may not be even anything to do with the circuit you have wired) then there is an investigation and the HSE say prove your work is safe and there are only two ways to do that one is to have proven manufactures test data or to have abided with current BS7671. When you can't prove that say sorry but that's not good enough. At best it's a heavy fine at worst it's a prison sentence and yes that can and dose happen!

There fore I'm not willing to risk it.

That's half the problem with today's electricians they aren't taught or given enough basic knowledge to enable them to think for themselves!!!
You should be able to prove each and every installation. If you need to totally rely on what BS7671 says to get things right, or more importantly what it ''Doesn't'' say, it's a sad day all round!! lol!!

 

[Heisenberg]

i've never said any of things so you must be mistaking me for someone else.
if fact im happy to admit to bending guidelines when i know an install will work perfectly fine.
i care not if others do also , thats their business.

and i'm only 41.
;-)

I wasn't meaning you in particular Biff, but I guess trouble just follows you around
The 'old timers' line was a metaphor for people that have been in the industry their whole careers, rather than a dig at people above a certain age.

I know that this forum comes down hard on people that are out of their depth, and rightly so. I just feel that sometimes those of us at the lesser end of the experience stakes can't really win

And whilst I might not be your senior when it comes to electrics, I got you beat on the race to the cemetery :angelsad2:

Cheers

 

[marshr02]

That's half the problem with today's electricians they aren't taught or given enough basic knowledge to enable them to think for themselves!!!
You should be able to prove each and every installation. If you need to totally rely on what BS7671 says to get things right, or more importantly what it ''Doesn't'' say, it's a sad day all round!! lol!!

Sorry - with respect - this is poor science. You can't think or apply basic knowledge in this specific example - in the absence of clear data from either manufacturers or standards bodies then the only way forward is either decades of experience OR carry out your own properly controlled tests. Anything else from say an electrician with 3 years experience is a wet finger in the air. Notice I am valuing the knowledge of experience electricans (say Biff for example), and not castigating recently qualified electricians for requesting clearer data - as they aim to work safely.

 

[Sparkytlec]

Sorry - with respect - this is poor science. You can't think or apply basic knowledge in this specific example - in the absence of clear data from either manufacturers or standards bodies then the only way forward is either decades of experience OR carry out your own properly controlled tests. Anything else from say an electrician with 3 years experience is a wet finger in the air. Notice I am valuing the knowledge of experience electricans (say Biff for example), and not castigating recently qualified electricians for requesting clearer data - as they aim to work safely.

That's what I was trying to say. But you put it better!

 

[Engineer54]

Sorry - with respect - this is poor science. You can't think or apply basic knowledge in this specific example - in the absence of clear data from either manufacturers or standards bodies then the only way forward is either decades of experience OR carry out your own properly controlled tests. Anything else from say an electrician with 3 years experience is a wet finger in the air. Notice I am valuing the knowledge of experience electricans (say Biff for example), and not castigating recently qualified electricians for requesting clearer data - as they aim to work safely.

To a point, you may well be right, but you'll never get absolute, or on the nail accurate data from the tables in BS7671 or even in manufacturers cable data. Both will include cover-all safety margins, more so it seems in BS 7671.

I'm not castigating the recently qualified electricians as such, it's the training they get at collage these days that's at fault. As for the fast track zero to thinking they are qualified 17 days to 5 weeks, well they stand no chance!! lol!!