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

[uksparks]

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.

 

[andyb]

That's different as you are changing circuit characteristics.

Then I'm not sure what's being debated here.

Can someone enlighten me please.

 

[Deleted member 26818]

So what about a cu change?
I test every circuit that I connect to a new board and put the results on an eic.

That's your choice, not a requirement of BS7671.
Just about any alteration or addition to a circuit, will alter the characteristics of that circuit.
All BS7671 requires, is that your work complies.

What's being discussed, as far as I'm aware, is whether an existing RFC is required to be tested after a spur has been added.

 

[andyb]

That's your choice, not a requirement of BS7671.
Just about any alteration or addition to a circuit, will alter the characteristics of that circuit.
All BS7671 requires, is that your work complies.

Do you test the installation Spin? (when changing a cu)
If not what paper work do you issue?

Interested, that's all.

 

[TJ Anderson]

Then I'm not sure what's being debated here.

Can someone enlighten me please.

Sorry Andy, went a bit off track there. The actual question was, as I read it, should we be carrying out L-N IR to the whole circuit when installing a spur to a RFC.

 

[TJ Anderson]

Do you test the installation Spin? (when changing a cu)
If not what paper work do you issue?

Interested, that's all.

You would have to, how else could you show the circuits were satisfactory (with BS7671) with your new OCPD's and RCD's if you did not issue an EIC. Although this is generally expected and is a practical way of showing compliance (it is what I do), I don't think it is a specific requirement of BS7671.

 

[andyb]

Sorry Andy, went a bit off track there. The actual question was, as I read it, should we be carrying out L-N IR to the whole circuit when installing a spur to a RFC.

That's fine TJ,

It seemed a straight forward thread about the scope of testing after extending a circuit.
The arguments started after Spin posted that It is prohibited to use either an EIC or MWEIC for the inspection and testing of an existing installation.

It got a bit silly after that and I'm still not sure exactly what was meant.

 

[andyb]

You would have to, how else could you show the circuits were satisfactory (with BS7671) with your new OCPD's and RCD's if you did not issue an EIC. Although this is generally expected and is a practical way of showing compliance, I don't think it is a specific requirement of BS7671.

Totally agree, always do.

I was just responding to post 32.

 

[Darkwood]

That's your choice, not a requirement of BS7671.
Just about any alteration or addition to a circuit, will alter the characteristics of that circuit.
All BS7671 requires, is that your work complies.

What's being discussed, as far as I'm aware, is whether an existing RFC is required to be tested after a spur has been added.

I would say that you need to ensure any work you do is safe and if this is an addition or extension of an existing circuit then you must confirm the safety and integrity of the circuit you have added to or altered and this can only be done by testing, digressing to the board change comment, if you change a board you are effectively modifying, altering the nature of all the circuits and you need to verify that any circuits you re-establish in your new CU are not unsafe, again to ensure your butt is covered this is done by testing and documenting with a Cert'.

Although I don't do domestic if I ever went to quote a job I would check the earthing, bonding and a quick test at the quotation stage of the circuit the spur was to be added to with no need to write it up at this stage to ensure your price covered all the work required to ensure your work would be connected to a safe ring main in the case of this discussion. There may not be any specific regulation but you are required to ensure any work you do is to regulation and is safe and where this means you have connected to existing then you also should make sure of the safety and integrity of the circuit you are adding/altering.

 

[Deleted member 26818]

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.

 

[uksparks]

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

 

[Deleted member 26818]

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]

Of course I issue EICs and MWEICs.

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

 

[DuaneMHunt1976]

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]

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]

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.