Spur sockets and ring mains

Theres an implied assumption in the whole design of a ring that large long duration loads will likely be "spread arround". ...
Only if one is within a certain distance of one end of a ring. If, as is very commonly the case, the CCC of the cable is 27A, then it is only within the first ~15.6% of cable from CU (at either end of the ring) that it matters. Once one is outside of that region, it is impossible to overload any of the cable, even if the entire 32A load is connected to a single point on the ring. In the 'worst case' allowed by regs (CCC=20A) that ~15.6% increases to ~37.5%.
I would assume the theory is that those who don't want to think too hard will follow the "informative" sections of the regs and more than likely end up with a reasonable result. Those who feel the need to ignore the informative sections can do so but they need to think harder about what they are doing.
I agree totally, but it's surprising to see how many seem to take the 'not thinking too hard' approach and hence think/talk of the guidelines as if they were regulations. In the case of two single sockets on an unfused spur, one doesn't really have to think very hard at all, or apply much 'discretion' - it's almost a non-brainer - yet we constantly see people seemingly expressing the view that it is simply 'not allowed'.

Kind Regards, John
 
Sponsored Links
Sponsored Links
Out of interest does anyone have the 15th and 16th editions to hand so they can tell us what they say on the subject of spurs and whether they say it in a "normative" or "informative" section?
 

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
Back
Top