Discuss 2 spurs coming from the same socket - NOT a spur from a spur! in the Electrical Forum area at ElectriciansForums.net

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HappyHippyDad

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Hello all..

I have recently added a spur for a customer and it got me thinking again about how many spurs could I actually take from the same socket!

The only socket I could use to take the spur from was on the ring and was already feeding a spur. Now I could have extended the ring but after a small amount of investigation I found that the existing spur was to a single socket hidden behind kitchen cupboards and never used so I disconnected and then fitted my spur.

It did make me think what was wrong with adding 2 spurs to the same socket though. The new socket was a crabtree and could easily accomadate 4 2.5mm conductors.

A double socket that is feeding a double socket spur has the (unlikely) potential to take 26A from the spur plus another 26A from whatever is plugged into it (therfore a maximum of 32A could flow through that one socket). By adding another spur to the socket the maximum it could take is not changed (still 32A).

I think the answer is that although possible its not a good idea to push the limit of a socket and by adding another spur I am pushing it closer to the limit of 32A more frequently which would be bad practice and unecessary as you can just extend the ring, but I'm thinking about it and need answers from the experienced chaps as otherwise I shall become frustrated!!!!
 
A poorly designed 32a ring can be loaded at more than 32a for a period of time before the OCPD operates.The only problem I can envisage with the scenario you describe is uneven loading of the ring circuit,with a possible considerable load at one point of the ring.That said as far as I'm aware there is no regulation preventing two spurs being wired from the same part of a ring.
 
look in bgb. appendix 15. 1 single or 1 double socket on an unfused spur. asny more, fuse down with a FCU to 13A.
 
A poorly designed 32a ring can be loaded at more than 32a for a period of time before the OCPD operates.The only problem I can envisage with the scenario you describe is uneven loading of the ring circuit,with a possible considerable load at one point of the ring.That said as far as I'm aware there is no regulation preventing two spurs being wired from the same part of a ring.

Thanks Wirepuller,
Thats what I was thinking but what would actually be wrong with that? I suppose the more unbalanced a ring the closer you are getting to a single 2.5mm taking 32A? (I know thats virtually impossible, just looking at the extreme to try and understand if an unbalanced ring is dangerous)

look in bgb. appendix 15. 1 single or 1 double socket on an unfused spur. asny more, fuse down with a FCU to 13A.

This would only be 1 socket on an unfused spur Tel, just 2 of them on the same socket (i.e 4 conductors in live terminal of socket)
 
This arrangement is OK, but as you say can tend to overloading at a particular point on the ring.
In reality the loading is not likely to be a problem unless these spurs are for water /air heating appliances.
You would still have to limit the maximum spurs to less than total points on the ring.
Normally the problem with two sockets spurred individually off a ring socket is space for the cables.
 
I'd also consider taking two spurs from one point a bit of a bodge job, I mean how much harder than that would it be to extend the ring?
 
2 x 26 = 52
Not sure if I'm reading you're post correctly if you have 2 x 2g socket of an existing 2g socket that is 6 socket on 2 legs of a ring . I agree unless these sockets are in a busy kitchen it is unlikely to be pulling at high end of OCPD but we just don't as we don't know if these sockets will get used for something different in future witch could cause issue
 
soz. misread the OP.
 
This arrangement is OK, but as you say can tend to overloading at a particular point on the ring.
In reality the loading is not likely to be a problem unless these spurs are for water /air heating appliances.
You would still have to limit the maximum spurs to less than total points on the ring.
Normally the problem with two sockets spurred individually off a ring socket is space for the cables.

Thanks Richard,
I think I would only use it as a last resort then, so it will probably never occur. I had a bit of a practice with the crabtree 2g socket and was suprised when 4 x 2.5mm conductors easily fitted in!

I'd also consider taking two spurs from one point a bit of a bodge job, I mean how much harder than that would it be to extend the ring?

Yes, It does seem a bit of a bodge doesn't it, just not quite sure why. You're quite right, not much harder to extend the ring, I was just interested in the facts and figures.
 
2 x 26 = 52
Not sure if I'm reading you're post correctly if you have 2 x 2g socket of an existing 2g socket that is 6 socket on 2 legs of a ring . I agree unless these sockets are in a busy kitchen it is unlikely to be pulling at high end of OCPD but we just don't as we don't know if these sockets will get used for something different in future witch could cause issue



Simon
I believe that most double sockets are rated for 20 amp continuous load only,they are not manufactured to be able to withstand a 26 amp load for a sustained period so are not rated as such

Add to that,the likelyhood of using a number of appliances in the same location that take anywhere near that load and the risks are reduced greatly

I agree,there are much better ways to make the addition,especially getting all your eggs in the one basket, but it may not warrant any code if it were an eicr
 
Simon
I believe that most double sockets are rated for 20 amp continuous load only,they are not manufactured to be able to withstand a 26 amp load for a sustained period so are not rated as such

Add to that,the likelyhood of using a number of appliances in the same location that take anywhere near that load and the risks are reduced greatly

I agree,there are much better ways to make the addition,especially getting all your eggs in the one basket, but it may not warrant any code if it were an eicr

That was another question of mine Des. What is a socket rated at? A junction box is clearly rated. A socket is acting much the same as a junction box so it should have a clear rating. Sockets state on them 13A, but what is that referring to as they clearly take much more than 13A? What is its rating?
 
the socket may only be rated for 20a but the connection is external to the socket, therefore if the connections are tight the socket is not loaded
 
Simon
I believe that most double sockets are rated for 20 amp continuous load only,they are not manufactured to be able to withstand a 26 amp load for a sustained period so are not rated as such

Add to that,the likelyhood of using a number of appliances in the same location that take anywhere near that load and the risks are reduced greatly

I agree,there are much better ways to make the addition,especially getting all your eggs in the one basket, but it may not warrant any code if it were an eicr

I was quoting OP
 
A double socket that is feeding a double socket spur has the (unlikely) potential to take 26A from the spur plus another 26A from whatever is plugged into it (therfore a maximum of 32A could flow through that one socket). By adding another spur to the socket the maximum it could take is not changed (still 32A).

!!!!
I might be misunderstanding this ?
 
I was quoting OP

Understood
2 spurs coming from the same socket - NOT a spur from a spur! {filename} | ElectriciansForums.net

I was only making available some information I had read
2 spurs coming from the same socket - NOT a spur from a spur! {filename} | ElectriciansForums.net
 
I changed a socket last week in a guys kitchen. It had three spurs off the ring in it! Five 2.5's do fit in a Crabtree socket, but by god did I swear! They all lunged out at me as I took the old socket off!
 
They might physically fit, but can you trust the terminal to make secure contact to all conductors at the same time? I can think of situations with four or five cables in one hole, three were clamped but the others fell out. Not an ideal setup, you must have put in some effort to get it back together as I can imagine the original workmanship not being of the best.
 

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