Full spread of tests after CU change.

[Guitarist]

I know that many electricians only carry out quick and basic tests after a CU change, but I thought I'd share this with you.
I am a fussy so and so, as many of you already know, so following a CU change I carry out every test imaginable. Having established no shared neutral, good bonding, good IR checks, etc. prior to carrying out said change, I got stuck in to a full spread of testing after installing it....
Was in the process of carrying out an R1+R2 test on every point in the lighting circuit, when I came across an open circuit at a bedroom ceiling rose... Checked switch, connections etc, but no joy. After half an hour in the loft, found the supply to the bedroom lighting joined in a JB but with the cpc ends not connected, just sitting there happily a few inches apart outside the JB, covered in loft insulation.
This is why I would rather be a few quid out of pocket time-wise, than skimp on testing.

 

[trev]

The whole forum is talking CU change , hence the topic title in bold letters above your post.
Glad you could join us Trev lol.

Yeah I get there eventually mate

 

[Guest55]

I don't. I just like to know what each RCD trips at.... I'm curious that way

The thing with being ultra thorough is that you always discover something you'd rather wish you hadnt lol.

 

[Guitarist]

My point really, in posting this thread, was simply to emphasise that although it's tempting to cut corners at times, there are times (especially on an old install) when doing all the tests not only gives you peace of mind, but can actually find a fault you really weren't expecting to find.

 

[Guitarist]

The thing with being ultra thorough is that you always discover something you'd rather wish you hadnt lol.

I know what you mean mate. Ignorance is bliss sometimes. Glad I found this one though, and the customer was happy paying me to sort it.

 

[VoltzElectrical]

I certainly don't test a new install the way I was taught at college. The main difference being the only RFC testing I do is end to end continuity of the 3 conductors at the C/U. If anyone would like to slag me off for this I would appreciate if you could accompany said slagging off with an example of how doing it this way could create a dangerous situation.

I will also happily admit that I get my R1+R2 readings after a C/U change by calculating Zs-Ze or R1+R2/4 in the case of an RFC. If they ask for an EICR I will give them one. If they want a C/U change with a cert, that is what they get.

ok, i will. I recently was doing a PIR on an installation and was doing Ze at sockets. Couldn't get a reading at one half of a double socket outlet. No earth. Go figure. If I had only tested at one point in the ring then nobody would have ever realised the danger of no earth present at an outlet. Big lesson learned.

 

[Rauer]

What cert do you now issue for a board change? I always have done an installation for the board , then a periodic for the circuits, but with periodics being replaced with eicr I assumed that it was now an installation and an eicr? Am I doing too much?

 

[Dave 85]

So you only do the tests which you deem necessary Dave?

Precisely

 

[Risteard]

Before I finish a job for good I like to do a ramp test on each RCD somewhere in the circuit, just for that last minute "nice" factor.

Never understood the rationale. An RCD must not operate at half of its rated residual operating current but must operate within 200mS for a BS type or 300mS for a BS EN type at its rated residual operating current. Once that has been satisifed then the RCD is compliant so what is the purpose of a ramp test?

 

[Guest55]

ok, i will. I recently was doing a PIR on an installation and was doing Ze at sockets. Couldn't get a reading at one half of a double socket outlet. No earth. Go figure. If I had only tested at one point in the ring then nobody would have ever realised the danger of no earth present at an outlet. Big lesson learned.

So what youre saying is one outlet of a double socket had no earth connection ?
Well thats a fault with the socket isnt it ? it wouldnt show up on any sort of cable tests ???
dont really understand your point.

 

[Dave 85]

What about polarity round your RFC? There was a guy killed not so long ago because of an L E reversal on a socket

Im not that stupid trev. Of that I am certain. I dont smoke drugs or drink before or during work either. The earth terminals on the sockets I use stand out like a sore thumb.

 

[Guest55]

What cert do you now issue for a board change? I always have done an installation for the board , then a periodic for the circuits, but with periodics being replaced with eicr I assumed that it was now an installation and an eicr? Am I doing too much?

In a word yes.
you use an EIC for your CU change but the schedule of test results is pretty much the same for an EIC and a EICR , so just one cert will suffice.

Unless of course the customer is paying for a EICR as well as the CU change , in which case issuing seperate certs is perfectly fine.

 

[Dave 85]

What cert do you now issue for a board change? I always have done an installation for the board , then a periodic for the circuits, but with periodics being replaced with eicr I assumed that it was now an installation and an eicr? Am I doing too much?

EIC for a CU change

 

[Dave 85]

To be honest the odds of someone being killed by a belt from an RCD protected circuit are slim to none in my opinion. I've had dozens of belts in my time on all types of circuit, and none of them have been particulalry bad.

 

[VoltzElectrical]

So what youre saying is one outlet of a double socket had no earth connection ?
Well thats a fault with the socket isnt it ? it wouldnt show up on any sort of cable tests ???
dont really understand your point.

exactly my point is that wouldn't show up on any cable tests thats why relying on end to end tests etc.. wouldn't have shown up this fault. The proper procedure of cross connecting line and earth then testing at EVERY point including BOTH outlets of of a double socket would have revealed the fault. what's not to understand?

 

[ExArmy]

got to admit I don't do both outlets on a double socket. how often are these faulty?