pir to installation time?

[Guest123]

jeez, get a qual for christ sake

Pardon me????

 

[uksel]

Oh dear

Zs - earth fault loop impedance
Ze - the value of earth fault loop impedance external to the installation
R1+R2 - is used as the value of earth fault loop impedance for the installation



not rocket science buddy

the thread was started asking if his particular regime prior to a CU was adequate.


'personally' I do an 250v IR test the board, reason:
people do tend to doctor their ringmains, which is often an issue, especially when people are tapping in and out, left right and centre creating parallel circuits and reducing the IR readings

'personally' i would NOT do the R1+R2 as a pre-check, because when upgrading the board everything will be RCD protected and earths dont tend to miraculously vanish from circuits. the ' continuity of protective conductors' i would test while doing the EIC

'personally' I also IR test @ 250v between every live and the neutral bar (removing the corresponding neutral) to make sure i dont have any borrowed neutrals

'personally' I also do the cont of ring final circuit conductors for the same reason as above, people tapping in and out or/altering circuits willy nilly

'personally' i would also check the bonding is in place


now every one is different, hence the 'personally's' and the advice given here is a personal regime of pre-checks BEFORE carrying out a CU change - which on completion would come with A COMPLETE EIC, SOTR AND SOI


is that a bit clearer now, i.e. simple enough for you to understand?

 

[andekoch]

Its interesting to see a sparky that actually does a full PIR before a simple board change in a domestic property. I always find it takes too long and puts much too much on the final price of the board change. I personally go and take a quick look, whip the board cover off to see if any circuits have been doubled up etc, then simply say that any faults upon change will be repaired at time and material. This has worked for me in the past years without any problems, it saves time, keeps your prices down and your customers happy,. Maybe I've been lucky, but up to now, I've never found too many big problems when I come to testing out.

At the end of the day, providing the IR vaules are ok and the RCD's don't trip, then any other findings can be reported in your cert and you can always then discuss repair costs.

Roukel, I always suggest to the client that I do a PIR first to make sure that there are no serious errors eg R1 + R2 or insul resistance (dont use technical terms though). I then quote the price for a PIR plus the price for a cu change, which in my case is around the 450 mark (incl material). I then do the pir a week before I do the board change.

Out of interest what do you charge for a cu change?

 

[Guest123]

r1+r2 isn't continuity of protective conductors - it;s the earth fault loop impedance of the consumers installation.

You Posted This Buddy!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

R1+R2 is a resistance measurement of the line and circuit protective conductors of a circuit.

Zs is an impedance measurement of the fault path of a circuit in the consumers installation PLUS the external path back to the transformer.

R1+R2 may be used in the calculation to detrmine Zs but it is NOT the impedance reading itself.

Clear enough for YOU to understand????

 

[uksel]

You Posted This Buddy!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

R1+R2 is a resistance measurement of the line and circuit protective conductors of a circuit.

Zs is an impedance measurement of the fault path of a circuit in the consumers installation PLUS the external path back to the transformer.

R1+R2 may be used in the calculation to detrmine Zs but it is NOT the impedance reading itself.

Clear enough for YOU to understand????

Zs = Ze + (R1+R2)

or in laymans (your) terms...

earth fault loop impedance = Earth fault loop impedance external to installation (Ze) + earth fault loop impedance of installation (R1+R2)

once again - fairly simples, and super basic, eek!

to take my quote, and look carefully, (it's in bold so you can be sure)

"r1+r2 isn't continuity of protective conductors - it's the earth fault loop impedance of the consumers installation"

consumers installation!!!

i.e. not the total earth fault loop impedance = Zs

and does not include the earth fault loop impedance external to the installation = Ze


i dont want to get people misreading quotes to be bitchy, but i've said my piece, explained what I meant over (and over,and over, plus having to repeat the basics of electrical knowledge), if you don't get it by now, you probably never will.

can we put this issue to bed, or am i seriously misreading this situation? cos' i'm getting pretty sick of explaining myself on what i feel is the most basic level here!



here's my take, you were under the impression i was advising that the r1+r2 (which is confirmed in the continuity of protective conductors, test 1, the most important) is irrelevant, this is not what i was advising

my advice was only relative to a pre-assessment of an installation prior to a CU change, to ensure that once you start the changeover, you do not discover real issues which can affect the systems integrity afterwards. ie. non-compliant results of test which were not affected by the CU change

because often mr joe bloggs (or the client) could misconstrue this as cowboy spark trying it on. it's damage limitation, we are in an age where people don't want to pay and the law protects them

so we, have to do everything we can (reasonably) to protect our time and assets from said ashmoles. ie. these pre-checks, or as the OP prefers a full PIR. it is all a personal take, and i have tried to give an opinion - which i honestly feel has been misinterpreted, maybe down to my poor wording, or your poor reading

but either way, i'm trying to act professionaly in the OP's best interests while taking on your personal vendetta.

I hope i contribute positively to this forum, but i certainly don't need this. and perhaps some outside opinion may help resolve it.

would you be open to a poll on the subject, so that it may be settled?

 

[G-dye]

I'm afraid uksel I have to side with lenny on this one.
he has offered his thoughts on your opinions which if you don't agree with is fine, but he is pointing out the facts

 

[uksel]

from what i can see we agree on the basic fact (or at least the forumla for Zs), but the context in which we use it differs?
we both know what R1+R2 is (we'd both probably be dead now if we didnt)
R1 - resistance of line conductor, R2 - resistance of protective conductor = YAWN

what we cant agree on is this...

I believe the value recorded of R1+R2 is only relevant to the EFLI

Lenny believes that it is only relevant to the continuity of protective conductors.

you want facts?

FACT:R1+R2 is a value automatically obtained while performing the test 'continuity of protective conductors' using test method 1, it is NOT A TEST in the sequence of tests as defined in GN3

FACT: THERE IS NO REQUIREMENT TO TEST FOR R1+R2, SO HOW CAN IT BE AN IMPORTANT TEST!!?!?!?

FACT: what if you decide to use test method 2 (long lead test) for testing continuity of protective conductors? no value for R1+R2, yet is this measured during any other test (other than ring circuits)

FACT: Zs is required, but is the only place I BELIEVE that the value of R1+R2 to be relevant (not cont of cpc's)


basically what it comes down to is this...

you say R1+R2

i'm thinking EFLI, lenny is thinking COPC
it's probably the way you are raised...




well... isn't this fun

 

[roukel01]

Out of interest what do you charge for a cu change?

Obviously depends on any extra work, but if its a straight swap and test, and I'm using an MK board then about 300 plus VAT

FACT: THERE IS NO REQUIREMENT TO TEST FOR R1+R2, SO HOW CAN IT BE AN IMPORTANT TEST!!?!?!?

I can see that UKSEL is getting a litle wound up about this, however, I thought measuring R1+R2 was in the sequence of testing as defined by GN3, obviously you have a choice, you either measure R2 directly using a wandring lead, or you measure R1+R2 by placing a temporary link in the board, please forgive me if I'm wrong, but I'm sure GN3 goes into this in some detail.

Saying that R1+R2 is the earth loop impedance of an installation, I feel is incorrect. Yes, we are all familiar with the Zs=Ze+(R1+R2) formula, however, if we measure Ze, and then took a Zs reading on a particular circuit, simply subtracting the two doesn't neccessarily give you the correct R1+R2 value because of parallel earth paths.

Lenny hit the nail on the head, testing R1+R2 is an important test, because it's a Dead Test and carried out before an installation is made Live, and therefore ensures a CPC is present before a circuit is energised or in a board swap situation, re-energised. (or you can just measure R2 directly, but lets fce it, a wandering lead is a pain)

 

[Guest123]

Look, I have no vendetta we'll just agree to disagree on this.

 

[WayneL]

Just to throw the cat amongst the pigeons - anyone know what page the R1 + R2 test is on in the Regs ha ha

 

[Guest123]

Just to throw the cat amongst the pigeons - anyone know what page the R1 + R2 test is on in the Regs ha ha

I would refer you to GN3.

And also respectfully request that you dont post comments in order to "stir up" people who are already a little wound up due to their own personal views and opinions on a topic (myself included), as this serves no purpose whatsoever.


Method 1 for continuity of protective conductors.

Step 3 for continuity of ring final conductors.

Polarity on a radial circuit.


Thanks.

 

[WayneL]

I would refer you to GN3.

And also respectfully request that you dont post comments in order to "stir up" people who are already a little wound up due to their own personal views and opinions on a topic (myself included), as this serves no purpose whatsoever.


Method 1 for continuity of protective conductors.

Step 3 for continuity of ring final conductors.

Polarity on a radial circuit.


Thanks.

I wasn't 'stirring up' your argument - what I posted actually has nothing to do with your argument, so chill.

I was simply pointing out that it is not mentioned in the regs, and offering a challenge, if you like, for anyone to find it.
People become that used to referring to R1+R2 that they automatically assume its in the regs.

It is, as you correctly state, a method of confirming continuity of protective conductors and polarity, not an actual test.

 

[Guest123]

Apologies to all.....a little stressed at the mo.

 

[roukel01]

I wasn't 'stirring up' your argument - what I posted actually has nothing to do with your argument, so chill.

I was simply pointing out that it is not mentioned in the regs, and offering a challenge, if you like, for anyone to find it.
People become that used to referring to R1+R2 that they automatically assume its in the regs.

It is, as you correctly state, a method of confirming continuity of protective conductors and polarity, not an actual test.

The regulations do not specifically comment on any testing procedures, that is not what the regulations are for. GN3 is the document you use for guidence on testing. And as we've already debated in length, GN3 states 2 methods of confirming continuity of CPCs, Method 1, measureing R1+R2 and method 2, measuring R2 using a wander lead.

 

[Guest123]

I agree, but the value obtained for one or the other method should be recorded on an EIC.

The thread has gone off-topic slightly (partly my fault) so I'll end my input here.

In relation to the initial enquiry by andekoch, on a pre CU swap I would check for presence and adequacy of earthing and bonding conductors, carry out a blanket I/R L+N - E, and end to end of any ring finals, similar to what has already been posted.

At least then the customer can be made aware of any lurking issues.