r1+r2. calculate or measure...

[sparkzalot]

Please discuss...

 

[GEOFF S]

First and foremost you're supposed to identify parallel paths and where possible remove them for testing purposes only - so you get a proper reading.

Agreed, though on lost of industrial/comercial you wont have much choice.

I don't agree that recording an incorrect and unreliable value as opposed to a tick in that situation would be the correct way to fill your cert in. But thats just my opinion. Each to their own.

The tick is there to verify continuity wher the reading is not reliable due to paralell paths for example.

My view on the 'tick' is that you're ticking to confirm that you've done the R1+R2 and that the reading isn't reliable.

Agreed

Mark.

Cheers

 

[markc123]

If the reading is unreliable then it is a fail.

No. Not necessarily. You can have a good reading that's still unreliable if parallel paths are present. All comes down to how you define unreliable.

 

[LankyWill]

My company just zs everything and calculate. Zs-Ze theres your r1+r2 i dont necessarily agree with this but for £25 for an intial test and inspect why not. Some mug countersigns everything and he has got the NICIEC stamp to his name so he is in the dock. Its wrong but sadly my company is quantity not quality they practically let anyone test as long as the figures vaguely look right. I guess if you IR okay and your Zs values seem legit its not that bad but it should be measure first and calculate if you cant power down. Regs cover you for both methods. Needless to say i am looking to move on.....

 

[markc123]

My company just zs everything and calculate. Zs-Ze theres your r1+r2 i dont necessarily agree with this but for £25 for an intial test and inspect why not. Some mug countersigns everything and he has got the NICIEC stamp to his name so he is in the dock. Its wrong but sadly my company is quantity not quality they practically let anyone test as long as the figures vaguely look right. I guess if you IR okay and your Zs values seem legit its not that bad but it should be measure first and calculate if you cant power down. Regs cover you for both methods. Needless to say i am looking to move on.....

r1+r2 isn't the same as R1+R2 so i hope this is a typo lol.

Yes, your company is wrong - bad practice and you're doing nothing but sucking pennies off unsuspecting customers. You're right, the 'mug' that signs it off will be in trouble one day if **** hits the fan. Unfortunately, people get away with this type of behaviour because nothing goes wrong. But if it ever did....

by doing R1+R2 you're confirming the earth is continuous before you make the installation live, so to calculate this is beyond stupid in my eyes.

 

[Toonlad]

I measure and record what my scam scheme provider cert asks for, either measure R1+R2 or do a R2, which one on the day I find works best for me. But I sort of see where the OP is coming from if you look at the Megger mft that will calculate R1+R2 for you, may have prompted the question also. I have never ever been taught or instructed to do it by calculation,as you have not physically proved the continuity/polarity by calculation.

 

[DuaneMHunt1976]

Right....
For one you have to MEASURE all the Loops in the Ring .. r1, r2 and rn NOTE ON SHEET

normally you do a calculation to see what about you will get for when you do R1+R2
what is (r1+r2)/4 ABOUT R1+R2

Then Cross over the In's and Out's of r1 and r2, this will give us R1+R2 at EACH POINT
(To look for the Highest Value, ie the worse case and if there is any SPURS)
This is ALSO NOTED ON SHEET

Zs
"This may be determined either by direct measurement at the furthest point of a live circuit or by adding (R1+R2) of column 6 to Ze. Ze is determined by measurement at origin of the installation or preferably the value declared by the supply company used. Zs=Ze+(R1+R2). Zs should be less than the values given in Appendix 2 of the On-Site Guide or Appendix B of GN3"
Furthest Point on a Ring, would be the about half way but maybe more on one side of the half way due to Sockets each adding a bit more Resistance each time, also Spurs. On a Big Ring or even a smaller one you would need to test a few sockets to measure.

If this was for Initial Verification you would do the FULL JOB MEASURED as the CIRCUIT is NOT IN USE AS YET.
And if doing a EIRC (Periodic Inspection Report) and if you cant Power down the Ring, then you would not have a figure for r1, r2 and rn, results can be gained by previous test sheets, could do R2 and long Lead.
Never seen the TICK before, a socket tester will confirm that R2 is present, dont need R1+R2 then, but i guess could tick that as well as the socket tester will confirm that as well.

 

[Deleted member 9648]

r1+r2 isn't the same as R1+R2 so i hope this is a typo lol.

Yes, your company is wrong - bad practice and you're doing nothing but sucking pennies off unsuspecting customers. You're right, the 'mug' that signs it off will be in trouble one day if **** hits the fan. Unfortunately, people get away with this type of behaviour because nothing goes wrong. But if it ever did....

by doing R1+R2 you're confirming the earth is continuous before you make the installation live, so to calculate this is beyond stupid in my eyes.[/QUOTE]

In the case of an EICR which is the subject of the thread the installation is already live.
See post #25 which gives the correct information.

 

[DuaneMHunt1976]

I think it would be good to do R2 if there has been some Word done on the circuit.
Just to know its there.. on a ring live its easy enough (socket tester)
Never know a plank might of left the Earth out.

 

[shanky887614]

r1+r2 isn't the same as R1+R2 so i hope this is a typo lol.

Yes, your company is wrong - bad practice and you're doing nothing but sucking pennies off unsuspecting customers. You're right, the 'mug' that signs it off will be in trouble one day if **** hits the fan. Unfortunately, people get away with this type of behaviour because nothing goes wrong. But if it ever did....

by doing R1+R2 you're confirming the earth is continuous before you make the installation live, so to calculate this is beyond stupid in my eyes.[/QUOTE]

In the case of an EICR which is the subject of the thread the installation is already live.
See post #25 which gives the correct information.

if its an eicr on an existing property then calcing it is fine as long as tye circuit was working properly before hand.

afterall you cant take a zs with no earth

 

[Dave OCD]

if its an eicr on an existing property then calcing it is fine as long as tye circuit was working properly before hand.

afterall you cant take a zs with no earth

Miraculously I've seen a Zs for lighting circuits with no CPC appear on certificates on more than 1 occasion. :banghead:

 

[Deleted member 9648]

Can I point out that the above quote isnt mine. oliceman:

 

[shanky887614]

Miraculously I've seen a Zs for lighting circuits with no CPC appear on certificates on more than 1 occasion. :banghead:

then its probably been made up from the van.

if it was tested 2 lead method on no-trip they wouldn't get a reading would they

 

[malcolmsanford]

You most likely find that if the result wasn't made up in the van it was most likely R1-Rn measured.

I have this in the back of my mind that the NICEIC issued guidance on lighting circuits that don't have CPCs in one of their docs. It was about class II accessories and board changes, and also dealt with the testing. part as well

 

[Dave OCD]

You most likely find that if the result wasn't made up in the van it was most likely R1-Rn measured.

I have this in the back of my mind that the NICEIC issued guidance on lighting circuits that don't have CPCs in one of their docs. It was about class II accessories and board changes, and also dealt with the testing. part as well

You'd think that would be clearly stated though if that was the case as that couldn't be called Zs but generally there are no recommendations or observations noted, just dodgy people who don't really know [or care] what they're doing sadly.