question on eicr

[soulman]

Hi,
While conducting an EICR on a RFC, end to end test is carried out on each conductor and a Zs at each socket outlet, the Zs always varies a little due to the resistance of the socket. So how on a periodic are you to determine whether there is a spur off a spur, as crossovers etc are not normally carried out. The reason i'm asking is recently i have done remedial works for EICR that someone else has done and found spur off spurs (one was actually 5 sockets into an extention) Yet this wasn't picked up. I have also asked experience electricians and got different answers. You are signing to state that the installation is safe, so this has got me thinking.

Cheers

 

[rich.250]

I always do a R1+R2 for exactly that reason.
As for varying sockets...
Try plugging your tester in and out a few times to clean up the contacts. Should all be the same.

 

[Farmelectrics]

The electrician hasn't done his r1r2 properly because if he had he would have noticed different readings at sockets which would of indicated spurts am I right in saying you can spur of a ring but you can't spur of a spur

 

[malcolmsanford]

Honest answer here would be ...................you sometimes miss things, and depending on the environment your working in there is often a lot you miss.

In a domestic situation I would hope that a competent person would get 90-95% of things right. I can not remember ever an inspection I have done on a domestic installation where full access to the installation as been denied, and I've done a few in my time. So I would be doing virtually a full set of tests and out of experience know what I should be getting on those results.

Commercial/Industrial is a different kettle of fish to be honest, I honestly feel because of restraints put on you and your testing, you can easily miss things, but this is where sampling and time frames are important and over time you hope to cover most of the installation.

Unfortunately testing is not a black or white process, and that is why as you say you ask 15 testers and will get many differing replies. The bottom line is safety and condition.

Yes you might miss a spur off a spur in some installations, though IMO you should not in a domestic one, but what you should not miss are things like heat damage, poor workmanship, and that niggle in the back of you mind, when you see something, you just feel it is not right, that is where that intangible comes in ....experience.

For me it is not competency, or degrees of it, it's experience for testing. My friends son is 28/29 and a very good young sparks and very competent, who now runs his dad's electrical contracting company, but when he does testing for large installations, he drags the old man out of moth balls to do it with him, not because he doesn't feel competent but the old man like me as mostly seen just about everything, and like me he as that intangible, that just don't seem right, let's have a delve into this.

So really back to your post, as the tester you have to decide what is safe and what is isn't. What tests you do and what you don't. If i found a RFC that was giving me varied and high Zs results then yes I would then start to do more tests and if possible carry out full testing on it, which would be RFC continuity, r1, rn and r2 followed by the R1 + R2 to see what I had

 

[snowhead]

You are signing to state that the installation is safe, so this has got me thinking.

Cheers

99.9% or better chance that the installation IS safe, it's just not compliant.

In most cases there will never be a problem with spur off spur, (and even off spur off spur).

There is more likely to be problems later with missed loose connections on an otherwise compliant installation

 

[rich.250]

99.9% or better chance that the installation IS safe, it's just not compliant.

In most cases there will never be a problem with spur off spur, (and even off spur off spur).

There is more likely to be problems later with missed loose connections on an otherwise compliant installation

Agree with the loose connection will cause problems.
But a spur off a spur could cause major problems if loaded up.

 

[Farmelectrics]

just a thought when you do spur of a ring ie 2.5 t&e it can only take 27a clipped direct but its on 32a breaker does this 40% value come in or there is a possibilty that single leg could over heat

 

[Farmelectrics]

allways been told not to spur off a spur we no it goes on wouldnt do it my self your thoughts

 

[rich.250]

A unfused spur can feed one single or double socket outlet, upto a length of 3m, the last part is often overlooked.
The same rule that applies to back fusing. i.e. you only need tails to carry max load of DB. if that makes sense
Answers in appendix 15