IR Testing... Am I missing a trick here?

uksparks · Aug 30, 2015

Hi,

I know this may seem like a stupid question, but here goes.

Example...

You have an existing RFC and spur off to a SFCU to feed a flood light for example.

Connect it up, do R1+R2, Zs etc,

but IR, I disconnect N and then run 250v as a start between L-N, then L-E, then N-E, then if all clear (acceptable reading say >100M), I do it at 500v and take the risk.

But first I go round the entire flaming house unplugging everything as there's no telling whats on what circuit, if its SP or DP sockets and just switching off may not be safe, or have missed something.

I know I can do it LN-E @ 500v, but am I missing a trick here?

My issue is, I get a lot of customers wondering why I am essentially interfering with the the rest of the house (unplugging stuff) just because I have fitted an outside light... People don't want me traipsing round their house when all they want is a new light.

I explain it to them, but what do you do? I feel I am doing too much.

Deleted member 26818 · Aug 31, 2015

uksparks said:
So spinlondon, if you clearly don't issue an EIC or MEWC for any work, what do you issue?

Of course I issue EICs and MWEICs.

uksparks · Aug 31, 2015

spinlondon said:
Of course I issue EICs and MWEICs.

Even on an existing install as it sounded like you don't?

DuaneMHunt1976 · Aug 31, 2015

Im having a hard time following this POST, as it sounds so AGRESSIVE to me.

So you wouldnt bother with a R1+R2 or R2 Test to make sure there is Continuity on Earth before doing the Zs (which is Live)
Isnt a good idear to make sure there is a Earth before POWERING UP!

Deleted member 26818 · Aug 31, 2015

Wouldn't you have first established earth continuity on the existing circuit before making the alteration?
Are you that unsure of your work that you need to check the new conductors you have connected are actually connected, before energising?

Darkwood · Aug 31, 2015

I think the confusion may be the preliminary tests to establish the work you wish to do can be done safely does not require documentation as your just confirming the work you wish to do, but on completion of the work then a cert' is issued in the normal manner, that's how I read Spin's replies and that seems all correct to me.

DuaneMHunt1976 · Aug 31, 2015

spinlondon said:
To be honest the problem reported by the OP is not one I have ever experienced.
If I need to disconnect appliances from a circuit so I can test it, they get disconnected.
Never had anyone complain about me having to do so.
BS7671 requires us before undertaking an alteration or addition to first determine that the existing equipment (including the supplier's) and earthing arrangements are adequate for the proposed new work.
There is no requirement to issue any certification or a report when doing so.
Once new work is completed, appropriate certification along with the results of any relevant tests is required to be issued.

How people determine that the existing installation is adequate is up to them.
Some will want to test the complete installation, others just the circuit being altered.
With an RFC, I would suggest it's a good idea to first check that it is in fact an RFC, that there are no breaks in the ring, and depending upon the alteration, whether RCD protection will be required. if yes, then an IR test would be to my mind a good idea.
In the OP's case, there is no requirement for RCD protection.
As such all that will be required, is an MWEIC recording the IR of the new conductors, the Zs and that polarity is correct.
The Zs test will prove continuity of the CPC.

Lets CUT OUT some of this WORDY RUBBISH

AT no POINT did you make say you were checking the CPC was Connected before you TURNED it ON.

AS it says on the "MWEIC"
ESSENTIAL TESTS
Earth Continuity Satisfactory
Insulation Resistance L-L and L-E
Earth Fault Loop Impedance
Polarity satisfactory
RCD Operations

spose to make sure a circuit is OK before POWERING.

As far as i know all this POST was GOING ON ABOUT, was asking about is the IR results OK!!

Deleted member 9648 · Aug 31, 2015

spinlondon said:
To be honest the problem reported by the OP is not one I have ever experienced.
If I need to disconnect appliances from a circuit so I can test it, they get disconnected.
Never had anyone complain about me having to do so.
BS7671 requires us before undertaking an alteration or addition to first determine that the existing equipment (including the supplier's) and earthing arrangements are adequate for the proposed new work.
There is no requirement to issue any certification or a report when doing so.
Once new work is completed, appropriate certification along with the results of any relevant tests is required to be issued.

How people determine that the existing installation is adequate is up to them.
Some will want to test the complete installation, others just the circuit being altered.
With an RFC, I would suggest it's a good idea to first check that it is in fact an RFC, that there are no breaks in the ring, and depending upon the alteration, whether RCD protection will be required. if yes, then an IR test would be to my mind a good idea.
In the OP's case, there is no requirement for RCD protection.
As such all that will be required, is an MWEIC recording the IR of the new conductors, the Zs and that polarity is correct.
The Zs test will prove continuity of the CPC.

This is one of the most pointless 'discussions' I've ever seen on this forum.
If a new addition is connected to an existing circuit then that circuit has been altered and should be tested AFTER the alteration to ensure compliance. What you are suggesting is testing only the addition PRIOR to connection, and testing the existing before any work takes place. This takes no account of a fault introduced when the addition is connected to the existing circuit!

Hellmooth · Aug 31, 2015

Spin being pedantic has caused a debate over nothing.......clearly we all know what happens with regards to testing and issuing EIC's and MWIEC's, Spin just decided to 'spin' it a bit........