bathroom bonding-again

[andypandy]

dinbatwrote in an earlier mail:

"547-03-03 - A supplementary bonding conductor connecting two extraneous-conductive-parts shall have a cross sectional area not less than 2.5 sq mm if sheathed or orherwise provided with mechanical protection or 4 sq mm if mechanical protection is not provided..."

6 sq mm does not come into it unless you are complying with 547-03-01 and 02, which deals with the situation where one or both of the extraneous-conductive-parts is an exposed-conductive-part. The requirement here is that the supplementary bonding conductor must be not less than half that of the protective conductor connected to the exposed conductive part/s. Both of these regs also state, "If mechanical protection is not provided, its cross-sectional area shall be not less than 4 sq mm."

And 547-03 is the regulation referred to in 601-01-01, dealing with supplementary bonding in bathrooms.

I still cannot see where the 6mm comes into the equation. For the cable to be 6mm and not less than half the csa of the "protective conductor" then we must be looking at some main bonding. However the main bonding cable would have to be 10mm and the main bond to my consumer unit is 16mm so this would not be adequate.
I can only find info that says that 4mm is the min. for bonding bathrooms without mechanical protection.
I seem to be chasing my tail with this one, so any help would be very much appreciated!

 

[securespark]

Not quite sure why you are chasing your tail on this one.

That excerpt you copied was from a post where there was some confusion as to whether 4mm2 or 6mm2 earth cable should be used for supplementary bonding in a bathroom, and it was cleared up - 4mm2 it is.

6mm2 used to be the standard for main earth bonding in the 15th Edition. The confusion arose because some people around here (naming no names, Jim - oops did I just say Jim, sorry!) are in a bit of a time-warp!!!!

No offence meant to anyone BTW!!

 

[Big_Spark]

hahahahaha

Nice post there Secure

However I also agree. I have always used 6mms for bonding, old habits die hard.

I would have been concerned if it was 4mm being used and 6mm required though!!

From a cost point of view there is not a lot of difference for the amount we use, and also we tend to use more 6mm G/Y than we do 4mm G/Y in normal use..normally is circuits using 10mm singles and for bonding in areas with heavy use, just sort of get into a habit and stick with it.

 

[securespark]

Wasn't really having a go...!

I know many people who do the main bonding in 10mm2 then carry on bonding in the bathroom with the same. As you say, as long as you don't use substandard sizes....

Simon

 

[andypandy]

right, that's that cleared up then!

thanks for the replies.

 

[ban-all-sheds]

Wasn't really having a go...!

I know many people who do the main bonding in 10mm2 then carry on bonding in the bathroom with the same. As you say, as long as you don't use substandard sizes....

Simon

Yo - but 10mm is a right bvgger to keep continuous and curled round the screws on the straps....

 

[securespark]

I keep the cable straight (ie the cable goes "straight through" the screw) or I guess you can crimp...

 

[ban-all-sheds]

I'm never happy with the amount of contact you get when it goes straight thru - always prefer it looped around, just like the example below labelled "Double wire"

 

[Big_Spark]

All connection on Earth Clamps should be CRIMPED connections to prevent them being accidentally pulled out of the terminal, and also to prevent undue oxidation of the contact between the copper of the cable and the metal of the clamp reducing the effectiveness of the connection.

 

[journeyman]

Oh well!

here

Back to the drawing board.

 

[Big_Spark]

According to the NICEIC they do not support the use of these clamps until such time as they have been fully approved by the BSi and the IEE, who are researching them.

There is concern because the clamp is made from non-conductive material and if the core does not make contact with the pipe, as intended, then the bond is useless.

Apparently MEM are looking into making an aluminium version.

 

[securespark]

Ban

Why does your lovely diagram show an earth strap on a plastic gas pipe???

 

[kendor]

I'd like to know what site he rips the drawings off from, and he doesn't acknowledge the artist's efforts in producing them either I just hope they aren't copyrighted!

 

[journeyman]

 

[ban-all-sheds]

I'd like to know what site he rips the drawings off from, and he doesn't acknowledge the artist's efforts in producing them either I just hope they aren't copyrighted!

If you look at the way that diagrams appear on here, you'll see that they are just links to the originals, wherever they are, so nothing is actually "copied" from another site. I suppose it would be an idea in future to explicitly add a caption that tells people where they are from, but the problem is that any URLs put in posts tend to get automagically transformed into the obscured format....