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Ed51

Rerouting Not Rewiring Cables - Need To Be Signed Off?

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Ed51

Rerouting Not Rewiring Cables - Need To Be Signed Off?
Rather a long post and lots of photos to look at. Appreciated if people can take time to read, look and reply.
See photos here, 


http://s807.photobucket.com/user/EarthTribe13/library/Electrician Forum


Cheers.


The property was rewired by my brother in law, who has a degree in electrical engineering. Rewire was done 34 years ago the property has been lived in all this time and there  have been no problems with the wiring. The kitchen wiring above the worktop was done about 25 years ago but the extension was never fitted out or used until recently.
I'm intending to reroute some of the cabling as at present is running along side of the doors looks very unsightly I have bought some trunking to put over  repositioned cables.
I'd like to make it quite clear I'm not adding any new cabling, wiring or spurs. I'm only redirecting the cable that is already there, just repositioning it. Though I will be connecting up the cable to new plug/switch boxes. I'd like to know as I'm only redirecting the existing cable. 
Am I under a legal requirement to have what I do, inspected and signed off by a fully qualified electrician  so as to avoid any problems with my house insurance being null and void?
You can see how unsightly things are at the moment. In photo A cable at bottom of box goes under floorboard. I lifted up floor board, there is a lot of slack cable there. I drilled a hole in ceiling beneath floor board, to reroute this cable. Cable above box in photo A ran along side of door up to ceiling, see photo A2 and A3 . Have drilled a hole in ceiling so can reroute cable away from door and cover with trunking. 
The box in Photo A on the skirting I'm intending to fit a new one on the wall. I've drilled a hole through this lathe partition wall, on the other side is a small room, I've drilled another hole on that side and lifted floorboard. Intend to pass cable under floorboard, through hole I drilled in ceiling beneath it. Have the rerouted cable run along ceiling under some trunking, then up through another hole I've drilled in ceiling, cable come up under floorboard in small room, then goes through wall to be connected to the box on the other side.
As I say any help, advice much appreciated.
Thank you.

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Sidewinder

Strictly speaking the IR for each circuit should be done, and recorded, then, the global IR calculated.

It is doubtful that on most new installations you would get anywhere near as low as 1M Ohm.

On an EICR, you should do a global IR, then and only then if it is low should you break it down, but sometimes that is not practical either.

However, the global should always be calculated, even if it is not recorded, because it can always be calculated from the individuals.

643.3.2 is pretty much the one that Risteard is on about I believe.

 

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binky

I'm not disagreeing with you, I just think you are mistaken :^O.

 

It would be very simple to have added a box for global IR on any cert - got shed loads of boxes for everything else. 

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Risteard
2 hours ago, binky said:

I'm not disagreeing with you, I just think you are mistaken :^O.

 

It would be very simple to have added a box for global IR on any cert - got shed loads of boxes for everything else. 

 

Have you read 643.3.2 then?

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binky

years ago.

 

Simple fact is if you look at any test cert there isn't any mention of global IR test results.  Now given that the various governing bodies that like to justify their existnece by making our lives more difficult have added pages and pages of codswallop to test certs but have failed to add a simple little box for what you are argueing..... This tells me you are in a minority of 1. 

 

However getting back to the original discussion of cable life, cable is, in most domestic situations, is definetly good for more than 25 years if installed properly.

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SPECIAL LOCATION
Quote

 

I'm not disagreeing with you, I just think you are mistaken .

 

It would be very simple to have added a box for global IR on any cert - got shed loads of boxes for everything else. 

 

 

1 hour ago, Risteard said:

 

Have you read 643.3.2 then?

 

 

I get the feeling were having a bit of misinterpreting what others are posting going on here.....

 

Just been scanning back over the thread...

I don't think anyone has actually said that bottom line IR acceptable value doesn't refer to the global figure...

 

Or that you can do a global test reading at the DB...

(if you want to)...

 

But one hell of a lot of the time individual circuits need to be tested as well to get the bigger picture about the condition of an installation ...

 

And 643.3.2  quotes detail relating to both Global and Individual circuit testing..

As does GN3, Examples (i) Global and (ii) Final circuit IR testing.. (Pg 51 onward)..

 

e.g.

eight final circuits all at 6Meg individual = Global 0.75Meg

Is a big difference than seven circuits at 200meg and one at 0.77Meg = Global 0.75Meg

 

OR...

eight final circuits all at 8Meg individual = Global 1.0Meg

Is a big difference than seven circuits at 200meg and one at 1.1Meg = Global 1.0Meg

 

In Both of the above example the second illustration has an installation where over 87% of it is in top-notch good condition only 12% is dubious..

whereas the first illustrations 100% of the installation has deteriorated down into single figure IR values...

 

If you just did the global value you'd miss an incredible amount of perspective on the condition of the overall installation for continual use and/or your recommended next inspection interval..

 

Hence why the schedule of test results have boxes for individual circuits NOT just a global value... 

(which would have been easier and neater with just one box))

 

As a side note...

during the old annual assessment watch the monkey do his tricks performance...

I have never been asked to do a "Global IR"...

get asked for Ze's,  PFCs,  R1+R2's,  Zs's,  Ring Continuities,  RCD trip times  and IR's on Final Circuits...

But NEVER a global IR!

 

 

Bit like when my car comes back from MOT...

 

I do rather like to see individual Tyre tread depth readings..

Not just a global  "All tyres are ok" comment.

 

Guinness 

Edited by SPECIAL LOCATION

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Risteard

As I said RECI always insist on a global insulation resistance test, and rightly so.

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Ed51
On 11/01/2019 at 11:28, phil d said:

Not rewiring could really affect the selling price, people may view, a lot may not if it says in the sales stuff that the house needs a rewire, then it's how much they'll knock you down by. A rewire may only be 2 or 3k, but add to that re-plastering, re-decorating etc and it all adds up. those that it doesn't put off completely may offer you anything up to £10k less, then it's whatever else a survey throws up. A lot of people are not practical today, they don't do diy, so they look at the cost of getting plasterers in, painters and decorators etc and it all  adds up.

As others have said, it would be better to get the work done before you sell, that way you can avoid a lot of problems.

Appreciate the sensible advice,

Thanks :)

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Ed51
On 11/01/2019 at 11:06, SPECIAL LOCATION said:

 

If you find an electrician that says they will...

 

I would make sure you don't employ them!

 

As that would appear to be a plastic enclosure, which hasn't complied with wiring regulations since Jan 16...

Ref wiring reg  421.1.201  requiring Non-combustible enclosure in domestic dwelling...

 

So you'd be unlikely to get a valid electrical certificate OR a building reg's compliance certificate for the work..

Which you will be needing if you want to sell the property without someone knocking a few grand off the price for electrical work...

 

Plus you will need to get RCD protection, that your Wickes board doesn't have. 

 

Guinness

OK thanks for that, appreciated :)

 

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binky
23 hours ago, SPECIAL LOCATION said:

 

 

 

I get the feeling were having a bit of misinterpreting what others are posting going on here.....

 

Just been scanning back over the thread...

I don't think anyone has actually said that bottom line IR acceptable value doesn't refer to the global figure...

 

Or that you can do a global test reading at the DB...

(if you want to)...

 

But one hell of a lot of the time individual circuits need to be tested as well to get the bigger picture about the condition of an installation ...

 

And 643.3.2  quotes detail relating to both Global and Individual circuit testing..

As does GN3, Examples (i) Global and (ii) Final circuit IR testing.. (Pg 51 onward)..

 

e.g.

eight final circuits all at 6Meg individual = Global 0.75Meg

Is a big difference than seven circuits at 200meg and one at 0.77Meg = Global 0.75Meg

 

OR...

eight final circuits all at 8Meg individual = Global 1.0Meg

Is a big difference than seven circuits at 200meg and one at 1.1Meg = Global 1.0Meg

 

In Both of the above example the second illustration has an installation where over 87% of it is in top-notch good condition only 12% is dubious..

whereas the first illustrations 100% of the installation has deteriorated down into single figure IR values...

 

If you just did the global value you'd miss an incredible amount of perspective on the condition of the overall installation for continual use and/or your recommended next inspection interval..

 

Hence why the schedule of test results have boxes for individual circuits NOT just a global value... 

(which would have been easier and neater with just one box))

 

As a side note...

during the old annual assessment watch the monkey do his tricks performance...

I have never been asked to do a "Global IR"...

get asked for Ze's,  PFCs,  R1+R2's,  Zs's,  Ring Continuities,  RCD trip times  and IR's on Final Circuits...

But NEVER a global IR!

 

 

Bit like when my car comes back from MOT...

 

I do rather like to see individual Tyre tread depth readings..

Not just a global  "All tyres are ok" comment.

 

Guinness 

totally concur, imho global testing is a short cut and nothing more!

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binky
23 hours ago, Risteard said:

As I said RECI always insist on a global insulation resistance test, and rightly so.

 

Who gives a monkeys about RECI? As you said yourself, they recommend this for new build. Existing installations have far too many variabes for this to be good practice.

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Risteard
18 hours ago, binky said:

totally concur, imho global testing is a short cut and nothing more!

 

How is it a shortcut? It tests everything and is the technically correct way of doing the test, unless you are going to subsequently calculate (1/Rt = 1/R1 + 1/R2 + 1/R3 etc.) - without calculating this you haven't actually established whether the insulation resistance meets the requirements of the Regulations.

18 hours ago, binky said:

Who gives a monkeys about RECI?

 

I do. I have to keep both RECI and the NICEIC happy. A huge percentage of my work requires RECI membership.

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binky

because it's quicker and easier than testing individual ccts if it works. I have used global testing in the past, but I really don't feel it tells you what is really going on with the individual ccts, for example, everything may test out at > 200 M Ohm bar 1 cct which is say 50M Ohm. This would suggest to me that that 1 cct needs closer attention if all the cabling is the same age and maybe  developing a fault of some sort / has suffered cable damage from when it was installed such as a back box screw nicking the insualtion. 

 

Global tetsing is a bit like speed limits. A modern car with modern brakes and suspension doing 70 mph on the motorway is a lot safer than an old Morris Minor doing the same speed in the same conditions yet for the purposes of the law both are considered to be driving safely...

 

BUt goingback to my prevoius point, if we were really expected to calculate global values there would be a box to fill on the test certs - lord knows we have hundreds of boxes to tick and  fill in these days! 

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Sidewinder

I was taught at college that the global must be calculated on my L2/L3 & on my 2391, when I did the stint as a 2391 examiner we required the candidates to calculate, but not record, just to confirm the individual readings tied up with the global that they were supposed to do.

W didn't fail them if they did individuals and calculated the global, or if they did individuals and measured the global, both was good, as it taught them the value of doing it.

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Sidewinder

 

Attached are some screen grabs from 7671 & GN3 (18th).

 

7671

643.3.gif

 

 

GN3

GN3 2.6.7-1.gif

 

GN3 2.6.7-2.gif

 

GN3 2.6.7-3.gif

 

GN3 2.6.7-4.gif

 

IMHO these reinforce Risteards point.

 

 

 

 

 

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binky

whre did the 20 MOhm figure come from? 

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Sidewinder
2 hours ago, binky said:

whre did the 20 MOhm figure come from? 

Guidance note 3, initial verification, testing.

The 4 screen grabs from GN3 follow on from each other.

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binky

but who decided the abstract figure and on what basis?  It's a bit like saying any earth rod over 500 Ohms is not good enough or is that 200 Ohms now - I've forgotten! 

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SPECIAL LOCATION
4 minutes ago, binky said:

but who decided the abstract figure and on what basis?  It's a bit like saying any earth rod over 500 Ohms is not good enough or is that 200 Ohms now - I've forgotten! 

 

You need to work the figures backwards..

 

AND..  remember the extracts quoted above are from the "INITIAL INSPECTION AND TESTING"  of a NEW installation part of GN3...

(e.g. NOT periodic inspection on an old existing installation section..)

 

so  if a new installation Global =20meg..   and you have:-

 

6 circuits this equals average  120Meg per circuit,  Or one low around 30Meg  + rest high  

8 circuits this equals average  160Meg per circuit,   Or one low around 30Meg  + rest high  

10 circuits this equals average  200Meg per circuit,   Or one low around 30Meg  + rest high  

12 circuits this equals average  240Meg per circuit,   Or one low around 30Meg  + rest high  

14 circuits this equals average  280Meg per circuit,    Or one low around 30Meg  + rest high  

etc..

etc..

etc..

 

Which..

For a brand new installation IMHO would suggest some dodgy installation work somewhere.?

 

AFAIK   

the 20Meg Global is another rule-of-thumb to indicate if you need to stop and do further investigations.

 

However...

Personally I still like to know the exact individual circuit figures as well so I can calc OR measure Global!

Guinness

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binky

as you said before Specs, given the amount of LED drivers and the like on ccts these days getting good test results is rather difficult even when using LN-E for IR at 250V. I also think we should be doing N-E loop tests. 

 

Anyway,  Risteard is clearly correct, although I can't think of a single electrician that does the global calc, apart from Risteard that is :^O.  I certainly don't remember ever being taughtt this requirement, but then my training was quite  afew years ago. As such, then IMHO a box should be added to test certs reflecting this requirement. It will also alter my Inspection testing going  forward - I've always regarded global IR as a short cut, but if that is the ultimate goal, then I shall be using it more going forward.

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Sidewinder
1 hour ago, binky said:

...I also think we should be doing N-E loop tests. 

...

You mean you don't?

Anyone who works with me does, how else can we confirm the L-N circuit is sound?

My site test sheets have always had this on them.

The global, I always estimate "on paper", because as Specs says it is better to have the individual values.

 

Also, remember that my quoted abstracts are for IV, not periodic.

 

For a periodic a global live:earth is fine, that is all lives together to earth, so single phase link L&N then IR to earth, as long as you don't have surge, any filters or similar L or N to earth connections, you'll get a valid reading.

If you get a low value then it's time to break down the circuits & do individual.

 

I'll mention to the guys on JPEL64 @ Elex Ally Pally if you want a global IR box on the certs...

 

I would guess that it might be a bit late now for Amd1, but Amd2 will be looked after 1 is out in a couple of years, so it might be able to go in.

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binky

I do N-E loops, but many don't as it's not taught or on the test certs

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Murdoch
10 hours ago, Sidewinder said:

I'll mention to the guys on JPEL64 @ Elex Ally Pally if you want a global IR box on the certs...

 

I would guess that it might be a bit late now for Amd1, but Amd2 will be looked after 1 is out in a couple of years, so it might be able to go in.

 

I laughed when I saw this.

 

Do the JPEL/64 clowns actually think about the ridiculous monster they care continuing to create? 

 

As far as I can tell the 18th edition is scrapping the bottle for changes and some of those included have nothing but "revenue" and "profit" written all over them ..................................

8 hours ago, binky said:

I do N-E loops, but many don't as it's not taught or on the test certs

 

I'm assuming you mean dead tests? 

 

I do the same on all work I do with builders involved!

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binky

Yep, dead tests. Nothing more annoying than a  neutral fault.

 

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Murdoch
38 minutes ago, binky said:

Yep, dead tests. Nothing more annoying than a  neutral fault.

 

 

Totally agree

 

I also do this on existing installations too confirm neutral continuity too ...

 

Many don't and don't understand the importance of this test

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