Too many or not enough..... - Page 2 - Electricians Forum | Electrical Forum | An electrical forum for electricians in the UK

Grae79 · 25-02-2008

still don't see the flaw...

the table's to be used if you can't be bothered to use the equation, basically. you have to use either one or the other to determine the cpc size.

01-03-2008

Quote:

Originally Posted by alan

The flaw is you have a table stating a fact that is not adhered to.
If it is different in other parts of the book it does not matter it is still a flaw.
And if the BS 7671 was law- you end up with one lawyer quote one rule and other quoting another. Which will be nonsense. I heard on the gripe vine that the 17th as a few flaws.

oh theres flaws allright

like appendix 15 which shows a radial circuit and describes it as 'starting and finishing at the distribution board' (or words to that effect)

that's a ring main to me

and the formula for getting rid of supplementry bonds in the bathroom (you know, as long as extraenous conductive parts are less than 1667 ohms to MET)

If you read the formula EXACTLY as it is written in the book you get a figure of over
383Kohms!!!!!