Spurring of a spurred socket

[Welsh_sparky_21]

Is spurring off a sockets that’s already been spurred off a major no no?? It’s for a socket behind a wall mounted tv so not gony be a major load on the cable

 

[Dartlec]

The wiring regulations are not statutory, and departures are permitted where it can be demonstrated that the resulting degree of safety is not less than that obtained by compliance.
Nobody can give a valid reason why a single socket spurred from another single socket itself wired from a spur is any less safe than a double outlet on a spur. There is no more chance of overloading the supply cable, or the outlets themselves, and it can be tested and verified in the same way as any other wiring.

I think if someone supplied a certificate for such work, noting the departure and attaching a risk assessment (even a simple one), then I wouldn't immediately consider it bad practise.

However, I wonder if there is more risk of maximum load being run on two single sockets, perhaps with multi gang extensions in each if they are the only sockets in the room - at which point you could run 14A through each without a fuse tripping. (Though these days there are fewer things outside of heating that get close to that of course)

Double socket designers clearly have decided that the risk of both outlets being run at maximum is low enough to justify their rating. In the case of single sockets the installer is becoming the designer and has to justify that risk.

If I were assessing the situation for continued use in an EICR I think I'd be working from the starting point of a C2 and looking whether there are reasons it should not be noted as such.

If it was in a bedroom with no heating and a heater or hairdryer might be plugged in I might judge it differently than if it was behind a TV as in this case and less likely to be used for anything else.

However, what would happen when the next owner comes along and decides to get that single socket replaced with a double by her handyman who isn't as careful as the original installer? Should the original installer be taking that possibility into account? I honestly don't know the answer to that... Would a judge consider him to have no responsibility if something were to occur?

The answer to the original question is clearly no it's not compliant. However it may well be safe in most circumstances, but possibly not all.

 

[radiohead]

"I think if someone supplied a certificate for such work, noting the departure and attaching a risk assessment (even a simple one), then I wouldn't immediately consider it bad practise.

However, I wonder if there is more risk of maximum load being run on two single sockets, perhaps with multi gang extensions in each if they are the only sockets in the room - at which point you could run 14A through each without a fuse tripping. (Though these days there are fewer things outside of heating that get close to that of course)"
Are you suggesting that an end user would think there is a difference between what he can plug into a single socket and a double socket?
It does not matter how many muti-gang extensions are run off a 13a outlet, they are protected against overload by a 13a fuse in the plug.

"Double socket designers clearly have decided that the risk of both outlets being run at maximum is low enough to justify their rating. In the case of single sockets the installer is becoming the designer and has to justify that risk."
Again, an end user will not differentiate between a single or double outlet, he sees a 13a socket and plugs whatever he wants into it

"If I were assessing the situation for continued use in an EICR I think I'd be working from the starting point of a C2 and looking whether there are reasons it should not be noted as such."
I disagree. I cannot see how a double outlet on a spur is safe and compliant but two single outlets are potentially dangerous. Illogical.

"If it was in a bedroom with no heating and a heater or hairdryer might be plugged in I might judge it differently than if it was behind a TV as in this case and less likely to be used for anything else."

"However, what would happen when the next owner comes along and decides to get that single socket replaced with a double by her handyman who isn't as careful as the original installer? Should the original installer be taking that possibility into account? I honestly don't know the answer to that... Would a judge consider him to have no responsibility if something were to occur?"
What if the handyman extends the ring in 1.0mm, what if he changes the OCPD for a 50a?
Those working with electrics in dwellings are required to be competent. We cannot be responsible for what happens to an installation after we have handed it over.
"The answer to the original question is clearly no it's not compliant. However it may well be safe in most circumstances, but possibly not all".
In which would it not be safe?

My answers in red

 

[Pete999]

Departures are permitted but there’s a difference between a departure and a non compliance

"I think if someone supplied a certificate for such work, noting the departure and attaching a risk assessment (even a simple one), then I wouldn't immediately consider it bad practise.

However, I wonder if there is more risk of maximum load being run on two single sockets, perhaps with multi gang extensions in each if they are the only sockets in the room - at which point you could run 14A through each without a fuse tripping. (Though these days there are fewer things outside of heating that get close to that of course)"
Are you suggesting that an end user would think there is a difference between what he can plug into a single socket and a double socket?
It does not matter how many muti-gang extensions are run off a 13a outlet, they are protected against overload by a 13a fuse in the plug.

"Double socket designers clearly have decided that the risk of both outlets being run at maximum is low enough to justify their rating. In the case of single sockets the installer is becoming the designer and has to justify that risk."
Again, an end user will not differentiate between a single or double outlet, he sees a 13a socket and plugs whatever he wants into it

"If I were assessing the situation for continued use in an EICR I think I'd be working from the starting point of a C2 and looking whether there are reasons it should not be noted as such."
I disagree. I cannot see how a double outlet on a spur is safe and compliant but two single outlets are potentially dangerous. Illogical.

"If it was in a bedroom with no heating and a heater or hairdryer might be plugged in I might judge it differently than if it was behind a TV as in this case and less likely to be used for anything else."

"However, what would happen when the next owner comes along and decides to get that single socket replaced with a double by her handyman who isn't as careful as the original installer? Should the original installer be taking that possibility into account? I honestly don't know the answer to that... Would a judge consider him to have no responsibility if something were to occur?"
What if the handyman extends the ring in 1.0mm, what if he changes the OCPD for a 50a?
Those working with electrics in dwellings are required to be competent. We cannot be responsible for what happens to an installation after we have handed it over.
"The answer to the original question is clearly no it's not compliant. However it may well be safe in most circumstances, but possibly not all".
In which would it not be safe?

My answers in red

Because a spur constitutes a single or a double outlet

 

[radiohead]

Because a spur constitutes a single or a double outlet

Only to those who behave like lemmings and are unable to actually apply some logic to whatever they are doing.
[automerge]1599416303[/automerge]
Utterly predictable red cross Pete.
No valid argument.
No logic.
No explanation for a point of view.

I respect any differing argument if you can actually put one forward beyond... 'because it is, ok'?

 

[littlespark]

Before any other scouser chirps in, I will quote one of their favourite phrases....

"Eeeh... calm down, calm down!"


No point trying to argue the case... BS7671 says its non compliant, therefore we shouldn't be doing it, or advising that its safe to do so.
Non compliant, if this is indeed an RFC, wired in 2.5, off a 32A OCPD.

The ideal solution has been suggested, early on.. (13A FCU supplying the spur) Arguing over why it 'could' be done, or speculating why it shouldn't just in case an idiot comes along later...
These conversations have no doubt been discussed before any regs were published, and they've come up with "only one unfused spur from an RFC"

 

[radiohead]

Before any other scouser chirps in, I will quote one of their favourite phrases....

"Eeeh... calm down, calm down!"


No point trying to argue the case... BS7671 says its non compliant, therefore we shouldn't be doing it, or advising that its safe to do so.
Non compliant, if this is indeed an RFC, wired in 2.5, off a 32A OCPD.

The ideal solution has been suggested, early on.. (13A FCU supplying the spur) Arguing over why it 'could' be done, or speculating why it shouldn't just in case an idiot comes along later...
These conversations have no doubt been discussed before any regs were published, and they've come up with "only one unfused spur from an RFC"

These are the same people who made 13a RCD protected socket outlets non compliant for additional protection in Bs7671 2018.

 

[Pretty Mouth]

Interesting discussion. I have often wondered why we are allowed a double socket on a spur, but are not allowed a single socket spurred from another spurred single.

BS7671 says its non compliant

Does it though? I know it's not permitted according to the design guide in app. 15, but which regulation does it break? (still talking about the singles scenario)

 

[Ian1981]

These are the same people who made 13a RCD protected socket outlets non compliant for additional protection in Bs7671 2018.

Because bs 7288 says they are not suitable for additional protection hence why they were removed.

 

[Pretty Mouth]

I dug this out from the 14th edition, am 3 1976. Back then, 2 singles could be fed from an unfused spur:

 

[radiohead]

I did my apprenticeship under the 14th and now you mention it I do recall something along those lines. I wish I hadn't thrown my copy of the 14th away, would make interesting reading now.

 

[Dartlec]

"I think if someone supplied a certificate for such work, noting the departure and attaching a risk assessment (even a simple one), then I wouldn't immediately consider it bad practise.

However, I wonder if there is more risk of maximum load being run on two single sockets, perhaps with multi gang extensions in each if they are the only sockets in the room - at which point you could run 14A through each without a fuse tripping. (Though these days there are fewer things outside of heating that get close to that of course)"
Are you suggesting that an end user would think there is a difference between what he can plug into a single socket and a double socket?
It does not matter how many muti-gang extensions are run off a 13a outlet, they are protected against overload by a 13a fuse in the plug.

"Double socket designers clearly have decided that the risk of both outlets being run at maximum is low enough to justify their rating. In the case of single sockets the installer is becoming the designer and has to justify that risk."
Again, an end user will not differentiate between a single or double outlet, he sees a 13a socket and plugs whatever he wants into it

"If I were assessing the situation for continued use in an EICR I think I'd be working from the starting point of a C2 and looking whether there are reasons it should not be noted as such."
I disagree. I cannot see how a double outlet on a spur is safe and compliant but two single outlets are potentially dangerous. Illogical.

"If it was in a bedroom with no heating and a heater or hairdryer might be plugged in I might judge it differently than if it was behind a TV as in this case and less likely to be used for anything else."

"However, what would happen when the next owner comes along and decides to get that single socket replaced with a double by her handyman who isn't as careful as the original installer? Should the original installer be taking that possibility into account? I honestly don't know the answer to that... Would a judge consider him to have no responsibility if something were to occur?"
What if the handyman extends the ring in 1.0mm, what if he changes the OCPD for a 50a?
Those working with electrics in dwellings are required to be competent. We cannot be responsible for what happens to an installation after we have handed it over.
"The answer to the original question is clearly no it's not compliant. However it may well be safe in most circumstances, but possibly not all".
In which would it not be safe?

My answers in red

I think the one statement I might take question with is:

"Are you suggesting that an end user would think there is a difference between what he can plug into a single socket and a double socket?"

Because I as an installer would know that a double socket is not rated at 26A (There may be ones that are - I actually don't know?) and would therefore have to take that into account when installing the circuit...

It's an interesting discussion and I'm not particularly wedded to my answer being the correct one or only acceptable one. Some of it was me thinking aloud and I welcome discussions like this which make me think.

If we take a large heater as the largest likely load on a socket outlet these days, then it is unlikely that two would be plugged into a double socket because of the limited length of the lead. It may be more likely that in a large room one could be plugged into each single socket though.

That may be an edge case though I agree - and whether it is something the installer should consider is something I don't know.

The regulations can end up taking some of the 'logic' out of the design part of installation, but following them (or more normally the OSG or various guidance based on them) makes life easier as it reduces the number of things that have to be considered when doing a simple job such as installing an extra socket, not to mention being a very easy way to prove to third parties that you have carried out a 'safe' installation.

They can also end up with slightly illogical circumstances I agree.

Some years ago as I was still finding my feet as a domestic installer I had a disagreement with an assessor because I had run a single twin and earth to a single socket from an empty 32A MCB (the only suitable one on the board).

If an RFC had been installed on that breaker, then taking a spur from the origin of the ring would have been considered OK, but running a single cable to a socket ended up as a radial on an inappropriate MCB in the inspector's judgement (and probably mine now).

Given that from another post, 2 single sockets was once specifically mentioned and is not now, I would feel that I don't have the expertise to install such a circuit and then defend it to an expert third party in the future.

Finding a circuit wired like that and judging its safeness is another issue - and I suspect that the majority of inspectors would code it as C2, but then I disagree with some of the things that NAPIT consider a C2, so each person would have to make their own mind up.

 

[davesparks]

While not technically compliant I can see no real problem with spurring a single socket from another single socket which itself is a spur.

In previous editions of the regulations this was permitted, but this was changed at some point to limit spurs to one point of any type.
I don't know why it was changed but can only assume it was done for a reason.

 

[Dartlec]

Just out of interest I priced it up and you could do a single socket and fused spur in the Click mode grid system for a bit over £5 - though not switched.

Handy way to spur off an existing twin socket without channeling out for a dual back box or a new fused spur - The spur would have to be connected before the socket in the grid system of course...

 

[ipf]

Well you should be.

I beg your pardon? I'm not into the IET Gestapo.

 

[pc1966]

I don't know why it was changed but can only assume it was done for a reason.

Probably because it is quite common for DIY changes from a single socket to a double. Then you end up with 4 * 13A outlet points on the spur.

While spurs are allowed, and occasionally make a lot of sense, I personally would like to see them banned! Actually, if they just stipulated only 2 cables per connection point then rings would be simple rings, radials would be linear radials, and testing a whole lot easier!