Fused spur from existing ring

GreySquirrel

Fused spur from existing ring

I want to put a fused spur from an existing.

Do I have to put the fused junction box in the ring so that the spur cable is fully protected?

or

can I use an ordinary junction box and start the spur with 2.5 mm^2 T&E and put the fused box further down the line of the spur?

or can I use an ordinary junction box and start the spur with 4.0 mm^2 T&E and put the fused box further down the line of the spur?

M cebee

hey-thought we clarified that already:)

the new rules says 'non-fused spurs not allowed'

imo that means you have to fit a fused spur 'on the ring' when you branch off-even with 4sq

i guess the thinking is that someone may branch off the 4sq later

GreySquirrel

M cebee wrote: »

hey-thought we clarified that already:)

the new rules says 'non-fused spurs not allowed'

imo that means you have to fit a fused spur 'on the ring' when you branch off-even with 4sq

i guess the thinking is that someone may branch off the 4sq later

This is a different spur.

I just wanted to be sure. I thought your answer would the right one.

M cebee

that's my understanding from reading the rules-i'm not gospel though:pac:

i think they clamped down on problems associated with rings-spurs being one of the main issues

GreySquirrel

My new (4th) regulations have not arrived yet.

I've extended the ring and got a dispensation from the wife to use mini trunking on the new segment.

All electrical items should have a WAF number - Wife Approval Factor number.

In the new reuglations is it an option that main overcurrent device goes in the meter cabinet or on the fuse board?

M cebee

i think it goes in the meter cabinet for new domestic generally

there's some exceptions

GreySquirrel

I've left the ring at this point alone and won't be putting in a spur.

Bruthal

As i always said, i think rings are more trouble than benefit. Dont think i have ever wired one.

Bruthal

Well maybe more trouble than benefit is bad wording, but what advantages do they have that 2 radials would not do, maybe a lower loop impedence, but not much else in a standard domestic setup? And after all, they are gone now except in kitchens, and in a kitchen whats the benefit that again 2 radials cant cover?

GreySquirrel

Just to clarify, I extended the ring to one side of the room and left the ring alone on the opposite. leaving the ring alone was more of a mechanical than electrical choice. I would have had to drill through a huge joist and up behind a skirting on a solid wall. then i woul have had to put in a fused junction box to run the spur.

I've got some trunking to cover in the extra cable.

Bruthal

You could possibly of reduced the ring circuit MCB to 20 amp and just spured straight out of it then, depending on how much load would usualy be on the circuit.

GreySquirrel

I suppose I could have split the ring and turned it into two radials with two 20amp mcb's but that would still leave me with the joist and skirting to do. Also I'm not sure of the exact route the ring takes when it leaves the room

the new sockets on the ring will be powering computer equipment. the room is my childhood bedroom which hadn't been decorated in over twenty years. i'm not sure when it was re-wired but i remember seeing some kind of certificate in my father's papers which i have to tidy up.

M cebee

voltage drop on the longer runs-they're advantageous that way

non-fused spurs and 'breaks' in the ring-are safety issues

they'll still have their uses on for DSO's and big distribution circuits

should prob be phased out of domestic use

btw-it's kitchens they're not allowed in

Bruthal

M cebee wrote: »

voltage drop on the longer runs-they're advantageous that way

non-fused spurs and 'breaks' in the ring-are safety issues

they'll still have their uses on for DSO's and big distribution circuits

should prob be phased out of domestic use

btw-it's kitchens they're not allowed in

Well its domestic use i mean that they have no big advantage in an average house, yes gone in kichens is what i should of said rather than "except in kitchens". Would of been tricky to put isolating switches on kitchen ring circuits possibly.

GreySquirrel

The ring is extended and in mini-trunking. Very neat, even though I say so myself.

Room ready for the new carpet.

Only a new backbox for the light switch and probably a new ceiling rose to be done. I can do these after the carpet man is gone.

GreySquirrel

GreySquirrel wrote: »

The ring is extended and in mini-trunking. Very neat, even though I say so myself.

Room ready for the new carpet.

Only a new backbox for the light switch and probably a new ceiling rose to be done. I can do these after the carpet man is gone.

Put in new back box and light switch only to discover the back box was all perished around the edges like it had melted. I it was new and in a sealed plastic bag.

Very annoying. Bringing the box and switch back to the store.