2 spurs from a Junction Box....worried?

[mikep83]

Hi folks.

I cut one of the cables on my ring circuit, attached the 2 now separate ends to a new 30a junction box, and then run 2 additional spurs from the same junction box, using 32a twin and earth, on the end of each of these new spurs is a twin plug socket with usb.

I did the work with my father in law, who’s an avid DIYer and has been doing diy for 60 years.

We did a really good job, cables cut nice, neat, secure, tested them, and all working.

Due to a rush to get the job done before decorators, I pre installed the new sockets and cabling, ready for the junction, and only then did I realise I should have extended the ring.....it was too late, I had sealed the walls up and could not get another cable in. We used a square 30a MK box, which had ample room for the cables.

These are bedside outlets, not for heavy consuming items.

Some forums and people have now put the fear of god in me that this is dangerous, however I have read mixed opinions (e.g. apparatly 1 spur from any point is the Reg, ok.....so I have 2 on mine, but is this really much different than if I added another junction 10 inches away for my second spur)

Is this really a concern to warrant me ripping it all back out?

It’s a good tidy job.
I know there’s regulations and partP......hindsight is a wonderful thing.

Views?
Many thanks.

 

[Pete999]

Excellent post, my only clarification would be about the point of connection. I'm not sure whether you are referring to the overload of the actual terminal block or other termination there?
If 40A was taken anywhere there would be an overload as normal which would be protected by the opd.
The actual issue of concern to that reg is overload in the cables rather than a point. This could come when the total load on the spurs would be 32A. This would not be an overload on the opd, but if (and only if) the shorter leg is less than 1/6 of the total length of the ring (assuming clipped direct), there could be an overload in that leg.
The intention of that reg is to ensure that is taken into account and considered unlikely.

On Site Guide page 76 7.2.2 Socket outlets:

The length represents the total cable loop length and does not include any spurs.

A rule of thumb for rings , infused spur length should no exceed 1/8th the cable length from the spur to the furthest point of the ring.

The total number of fused spurs is unlimited, but the number of non fused spurs is no to exceed the total number of socket outlets and items of stationary equipment connected directly to the circuit.

A non fused spur feeds only 1 single or 1 twin socket outlet or 1 permanently connected item of electrical equipment. Such a spur is connected to a circuit at the terminals of socket outlets or at a junction box or at the origin of the circuit in the distribution board.

A fused spur is connected to the circuit through a fused connection unit, the rating of the fuse in the FCU not exceeding that of the cable forming the spur and, in any event not exceeding 13 Amps. The number of socket outlets which may be supplied by a FCU is unlimited.

The circuit is assumed to have a load of 20Amps at the furthest point and the balance to the rating of the protective device evenly distributed (for a 32 Amp device this equates to a load of 26Amps at the furthest point.

 

[Pete999]

Excellent post, my only clarification would be about the point of connection. I'm not sure whether you are referring to the overload of the actual terminal block or other termination there?
If 40A was taken anywhere there would be an overload as normal which would be protected by the opd.
The actual issue of concern to that reg is overload in the cables rather than a point. This could come when the total load on the spurs would be 32A. This would not be an overload on the opd, but if (and only if) the shorter leg is less than 1/6 of the total length of the ring (assuming clipped direct), there could be an overload in that leg.
The intention of that reg is to ensure that is taken into account and considered unlikely.

On Site Guide page 76 7.2.2 Socket outlets:

The length represents the total cable loop length and does not include any spurs.

A rule of thumb for rings , infused spur length should no exceed 1/8th the cable length from the spur to the furthest point of the ring.

The total number of fused spurs is unlimited, but the number of non fused spurs is no to exceed the total number of socket outlets and items of stationary equipment connected directly to the circuit.

A non fused spur feeds only 1 single or 1 twin socket outlet or 1 permanently connected item of electrical equipment. Such a spur is connected to a circuit at the terminals of socket outlets or at a junction box or at the origin of the circuit in the distribution board.

A fused spur is connected to the circuit through a fused connection unit, the rating of the fuse in the FCU not exceeding that of the cable forming the spur and, in any event not exceeding 13 Amps. The number of socket outlets which may be supplied by a FCU is unlimited.

The circuit is assumed to have a load of 20Amps at the furthest point and the balance to the rating of the protective device evenly distributed (for a 32 Amp device this equates to a load of 26Amps at the furthest point.

Now someone please tell me that both, BS7671 Appendix 15 fig 15A and the OSG, both compiled incidentally by the IET are both wrong.

 

[SparkyChick]

On Site Guide page 76 7.2.2 Socket outlets:

A non fused spur feeds only 1 single or 1 twin socket outlet or 1 permanently connected item of electrical equipment.
Such a spur is connected to a circuit at the terminals of socket outlets or at a junction box or at the origin of the circuit in the distribution board.

Yes, I read this section of the OSG last night.

He has two spurs, one double outlet each (compliant), they originate from a junction box (compliant).

It says nothing about the number of spurs that can originate from a socket outlet or junction, only that they should originate from them.

But taking the OSGs guidance it to it's logical conclusion, is it wrong to take a spur from the supply side of an FCU, a SFCU, a 20A DP switch because the OSG doesn't explicitly list them as possible sources for a spur?

The OSG is guidance only, a watered down interpretation of the regulations for quick reference on site.

 

['mr2'gd4u]

So... I contact both the iet and the niceic. The iet went to voicemail but the niceic said it isn't Compliant... Now for my opinion It's fine as it is only used as a bedside socket, however you can't rely on the op removing it if he moves etc.

 

[Pete999]

Yes, I read this section of the OSG last night.

He has two spurs, one double outlet each (compliant), they originate from a junction box (compliant).

It says nothing about the number of spurs that can originate from a socket outlet or junction, only that they should originate from them.

But taking the OSGs guidance it to it's logical conclusion, is it wrong to take a spur from the supply side of an FCU, a SFCU, a 20A DP switch because the OSG doesn't explicitly list them as possible sources for a spur?

The OSG is guidance only, a watered down interpretation of the regulations for quick reference on site.

Your para three, it mentions 1 spur equates to 1 single or 1 twin socket outlet or 1 item of fixed equipment.
Para 4
No it does not preclude the items you mention

 

[SparkyChick]

Your para three, it mentions 1 spur equates to 1 single or 1 twin socket outlet or 1 item of fixed equipment.

Yes, he has two spurs, one double socket each... compliant.

 

[Pete999]

Yes, he has two spurs, one double socket each... compliant.

Fed from the same jb not compliant in my humble eyes.

 

[Spoon]

The iet went to voicemail but the niceic said it isn't Compliant...

Well that's interesting to know.
It will be interesting to see what the iet say about it when they get back to you.

 

[SparkyChick]

Fed from the same jb not compliant in my humble eyes.

Well yes... in your opinion it's not, in my opinion it is.

I could be swayed very easily with a regulation that prohibits it, but as far as I can tell, there is no such regulation. Thus as I've said, it may not be good practice (and we agree you and I are unlikely to use this method), but good practice is not the same as the regulations.

 

[Pete999]

So... I contact both the iet and the niceic. The iet went to voicemail but the niceic said it isn't Compliant... Now for my opinion It's fine as it is only used as a bedside socket, however you can't rely on the op removing it if he moves etc.

Interesting, thanks for contacting them Mate.

 

[Pete999]

Well yes... in your opinion it's not, in my opinion it is.

I could be swayed very easily with a regulation that prohibits it, but as far as I can tell, there is no such regulation. Thus as I've said, it may not be good practice (and we agree you and I are unlikely to use this method), but good practice is not the same as the regulations.

I'm not going to wave the white flag SC, but shall we agree to disagree?

 

['mr2'gd4u]

Interesting, thanks for contacting them Mate.

I had to put my own queries to bed on this matter so I had to contact them. It would be interesting to see what the iet do say, if anything, they tend not to call me back

 

[SparkyChick]

I'm not going to wave the white flag SC, but shall we agree to disagree?

Hell no, this is a fight to the death

I think it's quite an interesting debate because it highlights yet another ambiguity in the regulations that appears to be based on what people consider to make up the regulations.

As I've said all along, personally I wouldn't do it unless I had absolutely no other choice because I don't consider it to be good practice, I much prefer to extend the ring onto new outlets because it provides better options for future changes and greatly reduces the risk of someone down the line adding a spur from a spur.

So yes, we can agree to disagree

 

['mr2'gd4u]

Thing is I can to a degree agree with SC and Co. As it is essentially the same as running a ring and then spur off for every socket but I'm assuming that due to it being on a single point of the ring it's classed as 1 spur with 2 sockets on, even if the is no leg between the rfc and the jb.

 

[Pete999]

Hell no, this is a fight to the death

I think it's quite an interesting debate because it highlights yet another ambiguity in the regulations that appears to be based on what people consider to make up the regulations.

As I've said all along, personally I wouldn't do it unless I had absolutely no other choice because I don't consider it to be good practice, I much prefer to extend the ring onto new outlets because it provides better options for future changes and greatly reduces the risk of someone down the line adding a spur from a spur.

So yes, we can agree to disagree

That's good it was going to be hard to find a suitable venue for the final battle.