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Topic Title: C1, C2 and C3
Topic Summary: Flawed
Created On: 21 November 2016 11:37 AM
Status: Read Only
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 28 November 2016 09:20 PM
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dustydazzler

Posts: 1338
Joined: 19 January 2016

Separate phases in a box marked correctly with nice yellow warning labels on the consumer unit and wall switch no issue
Sometimes up and down mixed on landings we expect. But brand new house and the upstairs feed going through the common on the back door light switch and neutrals all in one connector not something you expect on a new build , hey ho
 28 November 2016 09:39 PM
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phantom9

Posts: 1757
Joined: 16 December 2002

Originally posted by: John Peckham

P9

You are going to have to explain why you think dead testing is a waste of time on an EICR? I would agree that R1 + R2 testing is a waste of time and Earth continuity can be proved by loop testing (GN3 agrees) but IR and ring continuity testing are appropriate tests if the installation can be isolated.


End-to-end tests of a ring circuit, yes. No other dead testing required. Insulation testing is a waste of time because to be done properly you need to isolate the circuit completely and remove all plugs from sockets and all lamps and starters from florries, all appliances from fcu's, all neons, all RCDs and its a fantasy list of required "inspections". That's more than what many others do based on some of EICs and EICRs I (rarely) get the pleasure of laughing at.

I do Ze, Zs and 30mA RCD x1/2, x1 x 5 and end-to-end on rings. on initial verification I do every test in the book, that's the only time I do. Sorry if that disappoints you but that's how real life is. I often wonder how big industrial installations get insulation tested. I gather the favoured testing in those is IR camera looking for hot locations. I have my doubts that the theory behind insulation testing holds any water. I have used it successfully to find dead shorts between conductors but how on earth it tells you the integrity of the insulation is a joke.
 28 November 2016 10:20 PM
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sparkingchip

Posts: 9953
Joined: 18 January 2003

I can't quite remember where I left my up to date copy of GN3, so perhaps someone else would like to type out word for word what it says about the requirement for end to end ring continuity testing when carrying out testing for a EICR.

Andy
 28 November 2016 10:42 PM
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leckie

Posts: 4323
Joined: 21 November 2008

It will be on your bedside table, you know, it's where you keep it to read while your drinking your bedtime cocoa.

Anyway, I think it says that the ring continuity test can be omitted if there are previous records of continuity test results....something like that.

I must agree with P9 that in a industrial installation it is often totally impracticable to carry out a meaningful IR test, even L/N - E. You cannot split circuits without dismantling the DB's in many cases. If it's wired in singles you can forget that, it's just not feasible. The problem is that if you take the measurement and it is low, what do you put on the report? It's probably leakage through old low bays or similar. So do you write C2, or FI? In both cases the result would be a report indicating "unsatisfactory". What further investigation should we suggest if asked? Get a cherry picker in, shut down production, just to unplugged some lights and find the wiring was satisfactory all the time? It's one of my bugbears with EICR's. I simply do not believe it when I see IR values of >299 recorded in test result schedules.
 29 November 2016 02:16 AM
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spinlondon

Posts: 5494
Joined: 10 December 2004

You won't like my EICRs then.
I use a Metrel so IR is >999.
 29 November 2016 06:52 AM
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psychicwarrior

Posts: 550
Joined: 18 October 2010

Eg. Broken CPC on a circuit that supplies class 1 light fittings of which one, downstream of the break, metal casing is live due to internal fault (but the light is still working).

How do you approach periodic inspection....industrial scenario (or otherwise) to get to an observation and a code?

Visual inspection, with circuit live, won't highlight it...unless one sticks a volt meter on it (and then it still might not present) or a tongue test. Efli test, but good luck with that in this scenario.

Or...Have a good look around, but don't be touching/opening (especially metal cased), to see if anything obviously dangerous or concerning. Then go dead testing to prove continuity of protective conductors first.

So for those that say isolating in some scenarios is just not practical, how else could it be safely done. The tests are in order for a purpose. A live efli test upfront not always possible.

Edited: 30 November 2016 at 07:16 AM by psychicwarrior
 29 November 2016 12:44 PM
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AJJewsbury

Posts: 15838
Joined: 13 August 2003

Insulation testing is a waste of time because to be done properly you need to isolate the circuit completely and remove all plugs from sockets and all lamps and starters from florries, all appliances from fcu's, all neons, all RCDs and its a fantasy list of required "inspections"

I'd expect a L&N - E insulation test on a small installation (say domestic sized) to produce sensible results without having to disconnect or dismantle too much.
- Andy.
IET » Wiring and the regulations » C1, C2 and C3

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