Ring Circuit Continuity on EICR (Figure of 8 ?)

[Guffer]

Hi

There seems to be some confusion at work about ring circuit continuity on an EICR. I was under the understanding that you took r1 & r2 added together and divided by 4, then during the live testing a Max Zs was measured using meter. The method two or 'figure of eight' is used only on Initial Verification or where there is no supply present.

This appears to be reinforced in both the old periodic and the new EICR dvd's created by the NICEIC where Tony Cable and his sidekick confirm that the figure of eight method is not requires on an EICR.

Why then do supervisors and inspectors insist on this method being used ?

Anyone able to enlighten me.

It appears to be the age old politically correct method v the financially viable method again !

Regards

Guffer

 

[Meggerman]

I'd never do figure 8 on existing rings. End-Ends, calc R1&R2 and record highest Zs, like you said.

 

[Deleted member 72666]

Then how do you know it's a true ring?

 

[trev]

You add the r1 and r2 and divide by 4, this is then the expected result when doing the figure 8 on an IV.

 

[Meggerman]

You add the r1 and r2 and divide by 4, this is then the expected result when doing the figure 8 on an IV.

Ok, but if you were carrying out an EICR would you actually carry out figure 8?

 

[trev]

Yes because it can rule out or reveal interconnections

 

[Deleted member 72666]

Yes because it can rule out or reveal interconnections

That was my point!

 

[trev]

That was my point!

Sorry mate, somehow I missed that post

 

[Guffer]

Sorry mate, somehow I missed that post

Thanks for the replies but we seem to be missing the point, its not do we do a figure of 8 as good practice, its do we HAVE to do one on an EICR ?

If we do, why do both NICEIC dvd's make a great point of telling us we dont.

Thats what i cant understand ?

 

[trev]

Imho yes we do have to do.

The NIC don't make the rules no matter what they might think.

 

[Meggerman]

Yes because it can rule out or reveal interconnections

I agree it can, I just know most don't do it.

 

[trev]

Which DvD is it that says this mate? I've not seen any of them and if I can catch a copy of it on youtube I'm going to email them to ask why they think a fundamental test is not necessary. I'll need to have the facts at hand before I open my trap though.

 

[Plonker 3]

Only way to verify a RFC is with the figure of 8 test, r1,r2 and rn test only prove there is continuity not that it could be a ring within a ring

 

[Guffer]

Which DvD is it that says this mate? I've not seen any of them and if I can catch a copy of it on youtube I'm going to email them to ask why they think a fundamental test is not necessary. I'll need to have the facts at hand before I open my trap though.

The NICEIC have released two DVD's for periodics, the older of the two is called 'Domestic Periodic Inspection Testing and Reporting' look round about the 40 minute mark and the more recent is called EICR 2011 with the juicy bit 59 minutes in.

There's no question of misinterpretation either, both scenes clearly state figure of 8 not required ?

 

[SirKit Breaker]

Not much has changed with periodics then, still a lot of misunderstandings.

GN3 is well worth a read, but even this won't clear things up any better. The main reason for carrying out periodics, is to ensure that the disconnection times can be met.

What you test and how you test it is left to your discretion depending on your initial findings, and chosen sample for what you see, and what if any records are available.

So even though we all have our own ideas and opinions, no one is really right or wrong, but i will go with testing the sampled circuits properly and fully for reasons that have been mentioned in earlier posts.

Cheers………….Howard

 

[Des 56]

I seem to remember a suggestion that ring circuit continuity does not have to be tested where there has been no alterations or additions to that circuit since a previous test and an installation certificate or EICR is available with the results

Here's a thought Why dismantle a circuit to verify what is already known

 

[SirKit Breaker]

Des you are bang on, and it also says that careful consideration should be given before dismantling or removing accessories as you could make a bad situation a lot worse. Some things are better left alone.

Cheers………..Howard

 

[gnuuser]

I seem to remember a suggestion that ring circuit continuity does not have to be tested where there has been no alterations or additions to that circuit since a previous test and an installation certificate or EICR is available with the results

Here's a thought Why dismantle a circuit to verify what is already known

the only reason i can think of is possible alterations that may not be visible
(ive seen this on a home inspection where a furnace transformer was hidden behind a plaster board wall)

 

[Des 56]

the only reason i can think of is possible alterations that may not be visible


Fair comment Gnuuser
Question to you, I thought ring finals were not used in that grand country of yours


I think my statement could be used in commercial or industrial situations where procedures are monitored
However,for a domestic customer or other less strict ind/com I would not heed my own suggestion

 

[gnuuser]

true almost all our systems are radials but on occasion i find some old houses wired with ring circuits (not very often though)

haha at first time i found one in an old house(way back when i was an apprentice) i had a hell of a time figuring out why it had power on both ends of the hot core when they were unhooked
the master was laughing his butt off
he knew what it was as soon as he saw the readings on the meter
we used to test the cores for the live one and label it for supply