B
breezer
ban-all-sheds said:
I agree this is not a text service, i had to read it twice to understand it
ring main in concrete or wall?
- Thread starter mikeh2000
- Start date
I agree this is not a text service, i had to read it twice to understand it
Sponsored Links
If you are going to use the argument that spurs can't exceed non-spurred sockets, as we need other sockets to consume some of the 30/32A ring capacity to make them safe, then you ought to be happy with this:
because as long as you're using more than one socket, your condition of the total capacity being shared is met.
If you really believe that the only way that spurred sockets can be safe is when current is being consumed elsewhere, then you should never fit unfused spurs, even for 1 socket, and you should never fit double sockets, because you cannot guarantee that even with a ring the only load won't be two 3kW heaters....
because as long as you're using more than one socket, your condition of the total capacity being shared is met.
If you really believe that the only way that spurred sockets can be safe is when current is being consumed elsewhere, then you should never fit unfused spurs, even for 1 socket, and you should never fit double sockets, because you cannot guarantee that even with a ring the only load won't be two 3kW heaters....
B
breezer
hmmmmmmmmmmmm blue sokets, nice 
do you recomend
these plug tops too
do you recomend
these plug tops too
Sponsored Links
2.5mm is rated at 28amps - the ring and spur system has been designed correctly.
i know it has been designed correctly and should be safe, however what happens if, for example,someone was to add a spur to that. if its on a 32amp breaker and the cable is rated at 27-28 amps then the breaker is not protecting the cable again overload upto 32 amps
Yes it is pushing the limit, and 4mm² would be safer under those conditions, but in reality, with 2.5mm² cable and a 26A load the socket itself would probably catch fire before the cable did.andrew2022 said:
The interesting thing is that even if you did use 4mm², it would still be aginst the regs because you'd have too many spurs off the ring...
Only if they are available with flashing lights inside.breezer said:hmmmmmmmmmmmm blue sokets, nice
(The reason those sockets are shown blue is that the pic is the 3rd of 3 in a series examining the unfortunate reality of my ring main layout - in the other two I show sockets on both floors, and I wanted to distinguish between the two. The upstairs ones are shown as grey, which is not a comment on my wife's cleaning abilities....)
That's why you aren't allowed to have more than one socket outlet on an unfused spur. With one socket, even a double one pushed beyond its safe capacity, the plugtop fuses give you 26A protection...andrew2022 said:
think we may be going round in rings here.
Take your point BAS. I seem to remember multiple socket non fused spurs were once allowed. Anyone know the history of which regulation change came first?
Where did you get the pic from?
Except, you might have a ring with no sockets and one spur? The more sockets there are, the less the risk of any one spur being overloaded. The rule would improve the chances that the spur could not be overloaded in small installations.
Actually it is pretty much the same problem if you plug the two heaters into the first or last double socket on a long ring.
Take your point BAS. I seem to remember multiple socket non fused spurs were once allowed. Anyone know the history of which regulation change came first?
Where did you get the pic from?
Except, you might have a ring with no sockets and one spur? The more sockets there are, the less the risk of any one spur being overloaded. The rule would improve the chances that the spur could not be overloaded in small installations.
Actually it is pretty much the same problem if you plug the two heaters into the first or last double socket on a long ring.
I drew it.Damocles said:
True. But AFAIK there's no reg to say that sockets must be accessible, so I could put in a ring using sockets under the floorboards as JBs, and spur off each one to another socket. Electrically identical to the above, and compliant....
Anyway - the above is what I will be doing, and if I can get 4mm² down to the sockets I will.
Maybe you should suggest a new regulation about making sockets accesible? Absolutely sure there isn't one?
Anyway, you know as well as I that you have 3 months left in which you can do whatsoever you please to your own wiring.
Anyway, you know as well as I that you have 3 months left in which you can do whatsoever you please to your own wiring.
Oh - a lot longer than that...
sockets have screw connections on the back
screw connections have to be accessible for inspection don't they?
now maybe if you resine encapsulated the back of teh socket it would be ok
afaict the only advantage of rings over 20A radials is that you can use a lot of power in one place and you save a tiny bit on breakers and CU capacity
screw connections have to be accessible for inspection don't they?
now maybe if you resine encapsulated the back of teh socket it would be ok
afaict the only advantage of rings over 20A radials is that you can use a lot of power in one place and you save a tiny bit on breakers and CU capacity
Well I reckon its down to using less copper. There used to be a shortage when they drew up the regulations.
Say, do you think someone has emailed that cartoon to john prescott? He may want to know what his boys have been up to
Say, do you think someone has emailed that cartoon to john prescott? He may want to know what his boys have been up to
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
Sponsored Links
