Adding a spur

[J4rman]

Hi

Im wondering if you can answer a question for me please as I can't find a definitive answer.

Do I need a qualified electrician to add an extra double socket via a spur or can I complete this myself?

The reason I ask is that the regs changed last year and I'm a little confused. I have fitted the socket to the wall but it just needs wiring in now. The distance from a suitable socket is around 3-4m and the 2.5mm T&E will be ran under the floor and into an unused space above the stairs (angled ceiling)

Is there a limit to how long a spur can be? I have read that 3m is max. It's a 2 bed house and there is a proteus rcd protecting the whole house.

Any advice would be great.

Thanks

MJ

 

[Taylortwocities]

You can do it yourself, there's no problem running a spur for that short distance.

Your only real issue to to check that the scket that you are connecting from is actually on a ring final and is not already a spur.

How many cables are there in the existing socket?

There is more guidance on the lovely WIKI at //www.diynot.com/wiki/Electrics:Socket-Circuits

 

[ban-all-sheds]

Your only real issue to to check that the scket that you are connecting from is actually on a ring final and is not already a spur

Continuities?

EFLI?

Polarity?

RCD?

 

[skotl]

Your only real issue to to check that the scket that you are connecting from is actually on a ring final and is not already a spur

Continuities?

EFLI?

Polarity?

RCD?

Sigh...

 

[ban-all-sheds]

So would you care to explain why those tests are not necessary?

 

[ericmark]

The 3 meter rule is questionable as to if it applies to socket supply. I would not worry too much about it. 434.2.1 is the regulation number.

What is far more important is the inspection and testing. It's not simply connect the wires and if it works it is OK.

An unfused spur relies on the fuse in the plug to protect the cable and as a result only one is allowed per connection to the ring final or 32A radial so the point where it is going to be connected to need testing to find out what it is.

In an ideal world if two cables come to the socket it's OK but we don't live in an ideal world so it needs testing.

In the day of the fuse having a cable a little too long would mean it took a little too long for the fuse to blow with a fault but it still would blow. But with the MCB which has replaced the fuse it is two devices in one. The thermal part is slow acting and will stop over heating but it is far too slow to protect against shock but the magnetic part is very fast but needs a lot of current to flow for it to operate. This is why we measure the earth loop impedance which unlike insulation resistance varies with the size of the MCB used.

The RCD to some extent has reduced the need for earth loop impedance measurements but again these can be faulty and again need testing and one can hardly measure 40ms with a stop watch.

Clearly many do fit sockets without doing the tests but also we do have fatalities and house fires as a result.

Over 25 years ago my father-in-law said to me I would never forgive myself if I didn't fit RCD's and my children were injured. So I fitted two RCD's which my lad did manage to trip so likely it did save him and allow him to become an electrical engineer as well. Yet my father-in-law also an electrical engineer never fitted them to his house. He did not have children playing radio in his house or stripping down computers.

It is the same in my mothers house she has no high powered equipment that she is likely to plug in causing any overload. At 89 she does very little. However if his or her house were sold or let to a family with children a re-wire and fitting of RCD protection would have to be done first.

It all comes down to a risk assessment. And I assess the risk of fitting new sockets without testing is too great. However I have a full test kit. I did look into the idea of testing without expensive equipment but found one needs at least 5 figure readings which you don't get with DIY measurement tools so impossible to test without special tools.

Having said that you can test for a socket being on a ring with simple multi-meters. You can also kill yourself trying to use one as often supplied with leads designed for extra low voltage only.

There is an old saying "Fools jump in where angles fear to tread."

 

[JohnW2]

Clearly many do fit sockets without doing the tests but also we do have fatalities and house fires as a result.

To be objective .... There are (very small numbers of) fatalities and house fires due to electricity. Whether (m)any of them are 'the result of' sockets being fitted without doing the tests is pure conjecture - and my guess would be that it is extremely rare, if not unknown, for that, per se, to be the cause of deaths or house fires.

There is an old saying "Fools jump in where angles fear to tread."

Indeed ... and, like many old sayings, it has definitely stood the test of time!

Kind Regards, John

 

[Taylortwocities]

There is an old saying "Fools jump in where angles fear to tread."

Obtuse, or acute?

 

[ericmark]

I would agree with John after a house fire it is hard to say if testing would have prevented the fire and there are very few fatalities.

Emma Shaw hit the head lines and is rather a high profile case of where testing or lack of it was blamed for the death.

Although there are other deaths due to poor installation and lack of periodic testing where the land lord has been fined the Emma Shaw one is only one I know of where the person responsible for testing (not person doing the testing) was found guilty.

However I think police and courts would be rather heartless to take a DIY person to court to prove they had killed some one in the house. The Emma Shaw case was well over 4 years before results were published as it was before 2008 so there was no RCD protection 31st of March the IET forum had "The Mr Hoult the NICEIC QS was found guilty last week of the charges relating to Section 7 of the Health and Safety at Work Act." and she died December 2007 the work clearly done before this date.

Although except for driving offences we have no statue of limitation I would consider after 10 years work should be retested so any faults are then down to the person who should have ordered the re-test or the person doing the re-test. I keep test sheets so I can show I did test and these were the results it's not to protect the house holder it protects me I can show what it was like when I left rather than what it was like after DIY work latter.

 

[JohnW2]

However I think police and courts would be rather heartless to take a DIY person to court to prove they had killed some one in the house.

Even if they did, I don't think that the absence of testing would be the main thing of interest to a Court. If someone had done something so dangerous that it was the main/primary cause of a subsequent death, then it would be that dangerous work which would be the main issue, rather than the absence of testing (which may, or may not, have detected the danger). Don't forget that there are some flavours of seriously dangerous work which would not be picked up by any testing - so doing the testing is no guarantee against subsequent prosecution for death/injury due to dangerous work. The main value of testing would be, in at least some cases, to detect the danger - which could then be rectified (so that there would be no subsequent death or Court hearing) - so it's really more in the interests of the person (DIYer or electrician) than anything else.

I keep test sheets so I can show I did test and these were the results it's not to protect the house holder it protects me I can show what it was like when I left rather than what it was like after DIY work latter.

I don't think you should derive much comfort from your belief that a piece of paper written by yourself would be taken by a Court to afford much proof of what you had or hadn't done

Kind Regards, John

 

[ban-all-sheds]

 

[JohnW2]

<nothing>

Kind Regards, John

 

[ban-all-sheds]

Changed my mind about adding a witty comment to TTC's one from this morning.

 

[Taylortwocities]

A cute what, perhaps?

 

[J4rman]

So from these replies I take it you recommend an electrician.

The socket only has two wires so is not a spur.

How much do you think an electrician would charge? The sockets and wall boxes are fitted and I will lift and refit the floor

Thanks

Mark