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.

 

[Guest55]

exactly. today another spark tried to tell me it had to be done on every circuit! i normally do it on each ring main(providing theres one on each side), at the socket with the highest ZS normally i figure if it works there it'll work eveythere else.
he said it was being thorough, i said it was wasting time! didn't go down well...

Well at least you know where to come for the real low-down on testing theory ;-D
And your collegue doesnt know his arse from his elbow.

 

[dim_bulb]

Why not 3probe test the rcd at c.u you can reset rcd and look at resultsAltought many instruments have auto recd

 

[Dave 85]

One lad I worked with refused to do it claiming he wasn't trained to as he didn't have 2391. I always thought a spark should be able to test his own work, some others refused to test a new install because "You know it's going to be ok" disgusting attitude

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.

 

[Guest55]

As long is nothing is plugged in to a socket then there can be no leakage and the test will be accurate.
The CU I just fitted has 7 RCBO's, so 7 lots of tests at the board. 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.

I wouldnt be ramp testing new devices to be honest.

 

[trev]

"The main difference being the only RFC testing I do is end to end continuity of the 3 conductors at the C/U"
Not a slagging but how do you prove polarity and IR

 

[Guitarist]

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.

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

 

[Dave 85]

I always IR everything trev. Polarity with a voltage tester on the tails

 

[Guitarist]

I wouldnt be ramp testing new devices to be honest.

Please explain why not Biff.

 

[trev]

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

 

[Guest55]

"The main difference being the only RFC testing I do is end to end continuity of the 3 conductors at the C/U"
Not a slagging but how do you prove polarity and IR

Your earth loop tester will go a long way in proving polarity at each socket although admittedly not infallable.
IR test can be a one hit global test before removing the old CU.
Like Dave says , if they want a detailed inspection they can pay for an EICR.

 

[Guest55]

Please explain why not Biff.

No I wont.
;-D

Only kidding.
Does the cert ask for the actual trip current for each device ?
So , where do you record the information ?

 

[ExArmy]

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.

thats fair enough for a new install. but when you have to do periodics on houses and you don't know how it's wired, you might want to do the rest of the tests just so you know whats what. recently i found what appeared to be a ring was just a load of radials spurred from the 1 and only point on the ring which was 6 feet from the DB, found by cross connecting L-CPC and testing each socket.
and about the R1+R2 reading for the cert, I always add r1 and r2 and divide by 4 and just write that down. thats what i was taught at college

 

[trev]

Just realised Dave is talking CU change I'm talking new install.
I'll stfu now

 

[Guest55]

Just realised Dave is talking CU change I'm talking new install.
I'll stfu now

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

 

[Guitarist]

No I wont.
;-D

Only kidding.
Does the cert ask for the actual trip current for each device ?
So , where do you record the information ?

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