advice

[spinlondon]

Excuse me, but I would suggest that it is you that is being argumentative.

As for your question you tell me.

Remember that the OSG is a simple guide to the requirements of BS7671, and electricians and electrical installers should always consult BS7671 to satisfy themselves of compliance.

The figures quoted in Table 4.1 of the OSG, are not the minimum allowed by BS7671.

However using the figures will ensure compliance with BS7671.

So no different to a 16th. edition board then?

There is no requirement in BS7671 for a board to contain any RCDs or RCBOs.

 

[ADS]

Excuse me, but I would suggest that it is you that is being argumentative.As for your question you tell me.

Remember that the OSG is a simple guide to the requirements of BS7671, and electricians and electrical installers should always consult BS7671 to satisfy themselves of compliance.

The figures quoted in Table 4.1 of the OSG, are not the minimum allowed by BS7671.However using the figures will ensure compliance with BS7671.

So no different to a 16th. edition board then?

There is no requirement in BS7671 for a board to contain any RCDs or RCBOs.

They are the minimum allowed for the stated 'Line' or 'Neutral' CSA.

Where it is desired not to calculate the minimum cross-sectional area of a protective conductor in accordance with Regulation 543.1.3, the cross-sectional area may be determined in accordance with Table 54.7

CSA of Line conductor (S) in mm sq

S < 16 - - - CSA of protective conductor = S

16 < S <= 35 - - - CSA of protective conductor = 16

S > 35 - - - CSA of protective conductor = S/2

How is the above 'Regs' quote not saying the same thing as Table 4.1 in the OSG???

It is stating the exact same thing - so like I said - unless you have 'incommers' of less than 16mm or bigger than 35mm, your 'Earthing conductor' will be 16mm - and your 'Bonding' will be 10mm.

Why are you arguing this?

 

[spinlondon]

Is there any point in continuing?

You have quoted Regulation 543.1.4, then ignored the information contained therein.

I'll try one last time.

There are two methods of determining the CSA of earthing conductors.

One is to calculate using the adiabatic equation as per Regulation 543.1.3.

The other method, if you can't be asked to do the calculation, is to use Table 54.7 as per Regulation 543.1.4.

Table 54.7 is a guide and the figures therin will ensure compliance with Regulation 543.1.3, but they are not the minimum required by BS7671. That can only be determined by calculation.

Why exactly do you think they suggest two methods?

Do you think that both methods will provide the same result?

Do the calculation for a 63A BS88 fuse, and then tell me what the minimum CSA is.

 

[Sidewinder]

ADS,

Spin has a point.

As I said in post #11 there is always the adiabatic.

If you have sufficient data.

Spin,

ADS has a point.

If you comply with the tables then you comply with the regs do you not.

 

[spinlondon]

I think you will find that I have stated that using the tables will ensure compliance with BS7671.

My point is that the minimum allowed by BS7671, and therefore the minimum required to be determined as adequate is not that as stated in the OSG, or in Table 54.7, but must be calculated.

If the calculation indicates that anything up to 12mm

 

[ianmacd]

I think you will find that I have stated that using the tables will ensure compliance with BS7671.My point is that the minimum allowed by BS7671, and therefore the minimum required to be determined as adequate is not that as stated in the OSG, or in Table 54.7, but must be calculated.

If the calculation indicates that anything up to 12mm

 

[spinlondon]

Yes it would.

The requirement is to use a CSA that is not less than half of what is 'required' for the earthing conductor, not half of what is actually used.

 

[ianmacd]

But since 12mm is not available you are required to have a 16mm conductor, therefore you need a 10mm binding conductor.

Now I know you will argue the oposite because, as ADS suggests, you are argumentative.

 

[spinlondon]

This is pretty basic stuff.

Something that was covered in the first year of my 2360 course.

It would appear that the newer courses don't cover as much.

I suggest you read the Regulation, and then consider why the word 'required' is used.

If the Regulation wanted the bonding to be half the CSA of whatever size earthing conductor is actually used, then the word 'required' would not be there.

 

[ianmacd]

The word 'required' is used because it may not actually be 'installed'.

 

[spinlondon]

The word 'required' is used because it may not actually be 'installed'.

If it's not installed, then how do you propose sizing the bonding conductors to it?

How about calculating what size it is required to be, and sizing to that?

Sound familiar?

 

[ianmacd]

If it's not installed, then how do you propose sizing the bonding conductors to it?How about calculating what size it is required to be, and sizing to that?

Sound familiar?

Yes so you agree it should be 10mm then. Thank god for that. Thought you were going to argue it for no good reason forever.

At least you have realised that by calculating it you know your required size would be a 16mm cable if its calculated at 12mm and therefore your Main Bonds would be 10mm

Thanks for agreeing Spin.

 

[spinlondon]

Grow up Ian.

The fact that you are unable to source the correct size of conductor has no bearing on the Regulations. If you decide to use a conductor size that is larger than that required, that is your choice. The Regulations require you to size according to what is required, not what is installed.

Consider what your actions would be if you required a 12mm

 

[ianmacd]

Grow up Ian.The fact that you are unable to source the correct size of conductor has no bearing on the Regulations. If you decide to use a conductor size that is larger than that required, that is your choice. The Regulations require you to size according to what is required, not what is installed.

Consider what your actions would be if you required a 12mm

 

[spinlondon]

Like I said in my previous post, grow up.

Your comments are childish and an obvious attempt to be insulting.

I have not suggested not installing 16mm

 

[ianmacd]

I'm sure that you didn't do that really, you imagined that potential copyright infringment .

I think we should just agree to disagree on this as I know I won't budge and I suspect you will not either. Doesn't make either of us any less wrong (or right).

P.S. Many consider my sence of humour very strange.

 

[spinlondon]

I'm sure that you didn't do that really, you imagined that potential copyright infringment .QUOTE]I was under the impression that you already had a hard copy, so no copyright would have been infringed.

Are you saying that the copy you downloaded last week is your only copy? Tut Tut.

You do know that there are errors in the early editions?