ring main in concrete or wall?

[mikeh2000]

Hi all,I'm just about to do a complete re-wire of my house,central heating system,burglar alarm and telephone system,oh and new kitchen units and bathroom suite!
The house is wired in such a way that all the downstairs sockets are spurs from above,and the kitchen is even worse than that,just a spur from above that s been spured on and on!
I'm intending to put a new ring main for downstairs as well as a seperate one for the kitchen but my question is this:
any ideas on what the best way might be to feed the sockets.I'm looking at either having the ring main for downstairs above the ceiling and dropping the cables down,or more ambitiously,gouging out the concrete floor and maybe putting the cable in some sort of conduit which would be a longer job but I feel safer in the long run.

 

[breezer]

dropping them down would be easier, plastic conduit will not not THAT much mechanical protection, where as steel conduit will, how ever, for steel conduit you will need an electrians pipe bender , 20mm di (and holder), tallow, and a lot of experiance, not to mention conduit fittings and conduit.

Easier to drop them down the wall and use steel capping

 

[kingkevbo]

you are right to get rid of the spurs, i had a similar setup in my house, but drop the ring down from the ceiling mate, thats how i have it, it is no less safe, as long as you bore the joists, dont chisel a channel thats against the regs now.

Chasing out concrete will take ages and wont be any safer, dont bother i say.

If you live in a flood risk area it would be better to have the ring high anyway!!

 

[mikeh2000]

Not quite in a flood area as I live in the highest town in dorset,famous for that hill in the hovis ad.
I had a think after I logged off and will probably go the way of steel conduit as I can get hold of all the parts,benders,dies etc etc.
As an addition is there any problem with the consumer unit being in the hall directly below the bathroom and also directly under the bath,taps end?

 

[paulfromswindon]

Sorry to criticise your choices mike, but are you really sure that you want to go to the hassle of steel conduit in a house? In 18 years, I have never seen anyone do that in a normal house. Wire it in normal cable via the first floor void matey, save yourself the time, aggro, and money.

Have a good one

Paul

 

[kingkevbo]

theres no problem with the consumer unit being there as long as the bath doesn't leak!!

No, seriously, there should be no problems but make sure the silicone sealant around the bath is all intact

It sounds to me that you are making a lot of work for yourself with this steel conduit idea, i am assuming that the wires are all already there for the ring main in the ceiling. You must be higly motivated, rather you than me chase out all that concrete!

 

[kingkevbo]

also you dont have to keep the downstairs sockets as spurs, you can wire them into the ring if you bring two cables down from the ceiling, it really would be so much easier

 

[mikeh2000]

not worried about the money side paul,I'm a maintenance engineer in a large factory and can get my hands on just about anything I need!
I'm going to be fitting a new bathroom suite(and floor now I've took the laminate off and noticed the rotten floor underneath!) so hopefully I shouldn't have a problem with leaks.

 

[breezer]

i still dont rcomend you use conduit, but good luck

 

[ban-all-sheds]

Fascinating - so there's at least 3 of us, me, mikeh2000 and spur-man whose sockets downstairs are spurs from up above.

Actually - probably 10's or even 100's of 1000's - I expect a lot of houses were built that way in the 50's. When did the rule about only being able to run spur cables from other sockets come into force, as some of my spurs come from JBs?

Thinking about what I've got, maybe mikeh2000 meant straight lengths of steel conduit buried in the wall, rather than a whole ring in conduit, then he wouldn't need bends or conduit fittings.

 

[mikeh2000]

my house was built in the late 60's I think,back when a packet of smiths crisps cost 5d according to an empty packet I found buried in a partition wall!
I wasn't going to use conduit for the whole ring but just as a bit of protection on the drops as my wife likes to hang a lot of pictures and such on the walls.

 

[paulfromswindon]

Ban - you can still run spurs off the ring via JBs, but most sparks avoid it when they can - makes fault-finding etc more difficult in the future. Sometimes it's unavoidable though.

Mike, i'm with you now, it would provide very good protection for the drops. We usually use plastic or tin capping, but it won't stop a drill -- people just push a bit harder! Conduit may be tough enough for people to take the hint. Another plus is that it would make it easy to rewire in future. Just be careful about the sharp edges at the top and bottom of the drops - I would bush it into the socket box..

Cheers

Paul

 

[ban-all-sheds]

My conduit has got rubber boots over the ends - are these still available?

Glad to see I can use JBs to take spurs off a ring (as that's what I've already got ).

Am I right though that I still can't have more spurs off the ring than there are sockets on it? And if so, is that a rule that makes any sense?

 

[paulfromswindon]

Dunno if you can get rubber boots - probably, i'd have thought. If not, put a coupler & brass bush on the ends - I think you can get ones that mean you don't need to put a thread on the conduit.

You are still correct that you can't have more spurs than there are sockets on the ring. It does make sense, cos people would decide it's easier to put two sockest on the ring, with 15 spurs!

 

[ban-all-sheds]

You are still correct that you can't have more spurs than there are sockets on the ring. It does make sense, cos people would decide it's easier to put two sockest on the ring, with 15 spurs!

Actually, no, it doesn't make sense. What would be wrong, i.e. unsafe, with 15 spurs and 2 sockets if 15 spurs and 15 sockets was safe? Consider the following "logic":

If I had a ring with 8 sockets on it, I could have 8 spurs, either from the sockets or from JBs - it makes no odds.

I assume that I would be under no legal obligation to ever actually use the sockets on the ring?

And that it would not be dangerous to not use them?

(If that's not the case, then please stop reading here, and refer me to the wiring regulation which states that a ring where none of the sockets are in use is forbidden.)

So if those sockets are never used, then they might as well not be there - I defy anybody to draw me a diagram which shows how the current flowing in different parts of the ring or along the spurs would be different between the situations of 8 unused sockets on a ring, or 80, or a ring of cable with no sockets at all.

I can certainly see the argument in favour preferring to only spur off sockets, because it makes the wiring more accessible, and I would certainly entertain the notion that more than 1 spur from the same socket is potentially unsafe because of the difficulty of getting a good connection with that many conductors in the socket terminals.

But I really cannot see why this:


====[socket]=====[socket]=====[socket]======
=======|==========|==========|
=======|==========|==========|
=====spur========spur========spur


is any safer than this:


====[socket]=====(jn box)=====[socket]======
=======|==========|==========|
=======|==========|==========|
=====spur========spur========spur


and if it's not safer, why is it required?


I can just tell that someone is going to say "none of this matters, that's what the regulations say so that's what you must do". But the problem is that every time a rule that cannot be justified prevents someone from doing what they want it lessens their respect for the rules in general, and makes them more dismissive of all the others, many of which do have genuine safety implications.

If the regulation which says "no more spurs than there are sockets" cannot be justified, then it behoves all of us, professionals more so, to lobby the IEE to remove it when they publish Edition 17.