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I`ve been thinking

OK the title might startle some who know me.

Ring Final rules.

What is the intention behind the rule "no more spurs than points on the ring".

I think most of us who have run rings would almost exclusively put every point on a ring and no spurs at all.

Spurs are then usually just additions.

One spur max per point.

One spur allowed at origin.

If I saw a ring with say 12 points on ring and one ring per point and say 1 point at origin that would be 12 on ring and 13 spurs that would not worry me.

In fact if I saw say 5 points at origin it would not worry me either.

If I saw 12 on ring each with one spur then 5 spurs at origin then 11 spurs on joints between points woul I worry?

No I would not although this "golden rule" would have been well and truly broken.

I think the rule intention was purely good housekeeping to keep us all on the straight and narrow.

In fact some on here have mentionded a ring in a loft with junction boxes dropped dow to spurs. Therefore all spurs and not on ring.

Note I did not pick the number of 12 points on ring for any reason, I could have picked 5 or 50 or 5000.
Parents
  • The 15th edition up to June 1987 in Appndx. 5 clarifies things a bit.(Page 120).


    "The minimum conductor size of conductor in the circuit and in non-fused spurs is given in Table 5A. (2.5mm2).However if more than two circuits are bunched together of the ambient temperature exceeds 30 deg. C, the size of conductor is increased and is determined by applying correction factors from Appndx. 9 such that the size then corresponds to a current-carrying capacity not less than


    20 Amp for circuit A1 (ring) i.e. 0.67 times the rating of the overcurrent protective device)."


    A non-fused spur is allowed to supply only one single or one twin socket outlet or one permanently connected equipment in this edition of the 15th edition.
Reply
  • The 15th edition up to June 1987 in Appndx. 5 clarifies things a bit.(Page 120).


    "The minimum conductor size of conductor in the circuit and in non-fused spurs is given in Table 5A. (2.5mm2).However if more than two circuits are bunched together of the ambient temperature exceeds 30 deg. C, the size of conductor is increased and is determined by applying correction factors from Appndx. 9 such that the size then corresponds to a current-carrying capacity not less than


    20 Amp for circuit A1 (ring) i.e. 0.67 times the rating of the overcurrent protective device)."


    A non-fused spur is allowed to supply only one single or one twin socket outlet or one permanently connected equipment in this edition of the 15th edition.
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