Seconded. To me it seems very reasonable in domestics, cpcs on a ring final may also be connected to boilers/water heating equipment pipes - and this the bondong conductors - and that will SIGNIFICANTLY reduce the R1R2 value to a falsely low value. Lights could also have supplementary bonding connected, in older properties bathrooms. You just don't know. Perhaps it's less significant in industrial.
I agree when testing continuity of cpc's in a commercial or industrial environment that parallel paths are virtually impossible to remove. Also the site installation is most likey under control of a competent person when any modifications are to take place. However, in a domestic installation the cpc of each circuit should be removed when testing to ensure parallel paths are not present. As a circuit could be missing a cpc. However, is earthed via metal pipework, which then a DIYer could swap for plastic pipe or fitting which the continuity of the cpc is lost for that circuit.
Well i’ll still be removing my circuit COC from the earth bar when testing my CPC continuity. Might aswell start doing Ze testing with parallel paths connected then. Don’t understand when you state it’s impossible to remove all the parallel paths. If the circuit CPC is removed from the earth bar, you’re not getting any. Even with a steel containment system thats using a separate CPC, there’s still no paths back via the earth bar. What the hell are you on about with regards wear and tear on the earthing terminal. Never heard so much guff man.
I agree with your viewer.The impact of parallel path is not minimal, it brings your R2 to 0 or close to 0.Example of installation wired in singles how you taking R1+R2 and how identifying the correspondent cpc, without disconnecting.
Mate this is the exact reason why you don't calculate R1+R2 from Zs. It's better practice to disconnect unless you can be 100% no parallel paths exist through other pcs or bonding connections. What's the purpose of the test... To verify the CPC continuity. You should try and do all you can to remove the parallel paths. Why are you encouraging people to do things worse... There's an argument to say you should verify CPC continuity prior to connecting in parallel paths when your talking about containment.... Honestly... This video comes across as petulant. I agree with the commenter... The picture in GN3 is just a picture... It doesn't support your argument... How many circuits on that picture.... What is going on efixx!
A parallel path through say plumbing + bonds will give acceptable performance. If that path is disrupted by plastic being put in the plumbing what happens to the circuit that was incorrectly relying on that path to achieve earthing? That's right. The earthing goes away. If you are proving continuity of an earth wire you must eliminate parallel paths one way or another. There's no question of it. Any standard that says otherwise isn't worth the paper it (often isn't these days) printed on. This is coming from an Aussie and we used to, and still can encounter, situations where all the earth wires are soldered together at the MSB.
All well and good, but anyone knows that removing the cpc from the bar is critical for any testing, not just r1 r2s. Case and point, i was doing a quick Zs on an old immersion. Got a reading. All ok? Nope. Was earthed via the water bonding. If i left the cpc in the bar doing just an r2 test id still get a reading. If i did an r1 r2 test with the cpc in the bar ive still got a reading. When in reality the cpc on the wiring had a break in it and wasnt continuous. If a plumber came along and put some plastic push fit stuff on somewhere you've then got an immersion with no earth. Guidance note 3 is just that - Guidance. You're still wrong and it facilitates bad practice.
You can even use an extraneous conductive part as a CPC. In practice containment is a perfectly reasonable CPC so you certainly dont need to disconnect that. If its been designed by someone like me then you may not even have a copper CPC because im not adding that to the project when the containment will more than adequately do the job.
For initial verification, I usually test the CPC continuity before terminating the cable into the CU anyway. For EICRs, I see both sides of the argument. Immersions, showers, etc. are 'risky', and likely to have parallel paths, so I try to disconnect the CPC from the MET for testing where feasible. Lighting and socket circuits are less likely to have parallel paths, so I may not disconnect. Note that it is possible to fudge re-connection of the CPC to the MET, thus leaving the entire circuit without a CPC. This would go unnoticed, unless testing to the MET, so there is a slight downside to disconnecting when testing.
I had this in my vid last week, I posed this exact question! I used to for that reason, finding a lighting circuit nicking an old immersion heater earth. That immersion heater getting disconnected would removed the cpc for the lights. Only taking out the circuits cpc when testing would show this. I’m in 2 minds with this
I don't think so. It doesn't contain live parts and/or single insulated live conductors, so it's not exposed conductive. It's probably not extraneous either, unless it's likely to introduce an external potential.
Domestics: cpcs on a ring final may also be connected to bonding conductors through boilers/water heating equipment - and that will SIGNIFICANTLY reduce the R1R2 value to a falsely low value. It wont be "absolutely minimal". The people who help to create GN3 would surely agree with what we are all saying here in the comments, at least acknowledge the thought process behind it. Lights could also have supplementary bonding connected, at the ceiling rose, in older properties bathrooms. Saw that plenty in social housing. I could see how it may be less significant in industrial, perhaps. But why risk picking up a parallel path when its a simple matter to drop the line and cpc in a wago.
Surely by removing the individual cpc from the Earth bar you have removed all parallel paths for that particular r2 and to promote leaving it in is not as accurate a reading ?
Bonding conductors should be removed from the earth bar for these tests but there is no real issue leaving all the final circuits linked together during testing. How would a socket circuit realistically provide a parallel path for a lighting circuit? You can spend 3 days testing a house removing every socket. What if socket 41 had a missing grommet? Testing is like all engineering and time is a resource. Spend it reasonably.
Couldn't agree more. In most instances, it is nigh on impossible to even get to the earth bar in a commercial distribution board due to the atrocious mess most of them are in. 😮
So for example: you have a socket in the kitchen for ignition on a gas hob. The circuit cpc is broken but this isn’t detected as the cpc is finding a path to earth via the gas bond. All good right? Tests perfectly fine!…. Gas works are undertaken and now the incomer is plastic or the bonding is disconnected. Now you have no earth (cpc) and nobody is the wiser. For the sake of undoing a screw instead of using those stupid magnetic links , 5 seconds of effort to undo and you are potentially preventing a dangerous situation. Regardless of what GN3 says I think we should be doing better.
Except you would notice that the reading doesn't match up with zs reading? For example ze is 0.30 Zs is 0.50 R1 r2 is 1.50... Then you would know something is up
@@calebbrookes7896this would mean you actually know what your doing 😂 some of these comments make me laugh. Love it when people like your self put a real life situation to these other idiots 👍🏽
Sorry efixx - really disagree here. The real world effect is far from minimal. A cct such as immersion radial could test out fine with parallel paths in place through the pipework, when actually the earth is only being found via bonded pipework.
😂😂 brilliant this is the way to deal with someone who calls you out.... i don't disconnect the cpc either unless i get a ready i feel needs looking at....
@mikethemask1525 I don't agree with calling out anyone, I think it is more about learning, and if we can all get something out of it, then it's fantastic. But I fully disagree with the video, and people need to be very careful as they can get caught out .
Likelyhood of parlel paths when testing R1+R2 and you removed CPC from. Earting terminal is very very low. Certainly lower considerably than when in the earth bar. Just goest to show how low the standards can be according to regs... just sad.
Testing the resistance of the CPC (Circuit Protective Conductor), even with satisfactory results, cannot guarantee that the conductor is continuous and unbroken at all points. The R1+R2 test is often considered inadequate in real-life applications, particularly in industrial settings where each point of the CPC is connected to metal parallel paths (such as metal structures or conduits). While the R1+R2 test may be suitable for domestic installations (like flats), its effectiveness diminishes in industrial plant rooms due to the presence of multiple grounding paths that can lead to misleading results.
I agree with your viewer, many missed situations arise from not disconnecting the cpc.
Seconded. To me it seems very reasonable in domestics, cpcs on a ring final may also be connected to boilers/water heating equipment pipes - and this the bondong conductors - and that will SIGNIFICANTLY reduce the R1R2 value to a falsely low value.
Lights could also have supplementary bonding connected, in older properties bathrooms. You just don't know.
Perhaps it's less significant in industrial.
Your viewer is still correct. You should be removing the CPC .
I agree when testing continuity of cpc's in a commercial or industrial environment that parallel paths are virtually impossible to remove. Also the site installation is most likey under control of a competent person when any modifications are to take place.
However, in a domestic installation the cpc of each circuit should be removed when testing to ensure parallel paths are not present. As a circuit could be missing a cpc. However, is earthed via metal pipework, which then a DIYer could swap for plastic pipe or fitting which the continuity of the cpc is lost for that circuit.
Well i’ll still be removing my circuit COC from the earth bar when testing my CPC continuity.
Might aswell start doing Ze testing with parallel paths connected then.
Don’t understand when you state it’s impossible to remove all the parallel paths. If the circuit CPC is removed from the earth bar, you’re not getting any. Even with a steel containment system thats using a separate CPC, there’s still no paths back via the earth bar.
What the hell are you on about with regards wear and tear on the earthing terminal. Never heard so much guff man.
I agree with your viewer.The impact of parallel path is not minimal, it brings your R2 to 0 or close to 0.Example of installation wired in singles how you taking R1+R2 and how identifying the correspondent cpc, without disconnecting.
Mate this is the exact reason why you don't calculate R1+R2 from Zs. It's better practice to disconnect unless you can be 100% no parallel paths exist through other pcs or bonding connections. What's the purpose of the test... To verify the CPC continuity. You should try and do all you can to remove the parallel paths. Why are you encouraging people to do things worse... There's an argument to say you should verify CPC continuity prior to connecting in parallel paths when your talking about containment.... Honestly... This video comes across as petulant. I agree with the commenter... The picture in GN3 is just a picture... It doesn't support your argument... How many circuits on that picture.... What is going on efixx!
A parallel path through say plumbing + bonds will give acceptable performance. If that path is disrupted by plastic being put in the plumbing what happens to the circuit that was incorrectly relying on that path to achieve earthing? That's right. The earthing goes away. If you are proving continuity of an earth wire you must eliminate parallel paths one way or another. There's no question of it. Any standard that says otherwise isn't worth the paper it (often isn't these days) printed on. This is coming from an Aussie and we used to, and still can encounter, situations where all the earth wires are soldered together at the MSB.
All well and good, but anyone knows that removing the cpc from the bar is critical for any testing, not just r1 r2s. Case and point, i was doing a quick Zs on an old immersion. Got a reading. All ok? Nope. Was earthed via the water bonding.
If i left the cpc in the bar doing just an r2 test id still get a reading. If i did an r1 r2 test with the cpc in the bar ive still got a reading. When in reality the cpc on the wiring had a break in it and wasnt continuous. If a plumber came along and put some plastic push fit stuff on somewhere you've then got an immersion with no earth.
Guidance note 3 is just that - Guidance.
You're still wrong and it facilitates bad practice.
I learned this in class last week. Was a hot topic of discussion 😂
You can even use an extraneous conductive part as a CPC.
In practice containment is a perfectly reasonable CPC so you certainly dont need to disconnect that. If its been designed by someone like me then you may not even have a copper CPC because im not adding that to the project when the containment will more than adequately do the job.
For initial verification, I usually test the CPC continuity before terminating the cable into the CU anyway.
For EICRs, I see both sides of the argument. Immersions, showers, etc. are 'risky', and likely to have parallel paths, so I try to disconnect the CPC from the MET for testing where feasible. Lighting and socket circuits are less likely to have parallel paths, so I may not disconnect.
Note that it is possible to fudge re-connection of the CPC to the MET, thus leaving the entire circuit without a CPC. This would go unnoticed, unless testing to the MET, so there is a slight downside to disconnecting when testing.
I think the wear and tear on loosening and tightening an earthing terminal is what I would call minimal.
Agreed. It was a ridiculous thing to say.
More like lazyness to go all the way to the other end with the measuring lead.
@@travoltasbiplane1551 clutching at straws is what this vid is all about. This channel has gone electrically woke🏳️🌈
You could argue it actually improves it by removing oxidation.
I had this in my vid last week, I posed this exact question! I used to for that reason, finding a lighting circuit nicking an old immersion heater earth. That immersion heater getting disconnected would removed the cpc for the lights. Only taking out the circuits cpc when testing would show this. I’m in 2 minds with this
Tray is exposed conductive not extraneous, correct?
I don't think so. It doesn't contain live parts and/or single insulated live conductors, so it's not exposed conductive. It's probably not extraneous either, unless it's likely to introduce an external potential.
Exposed parts would be the actual case of a class 1 appliance, like a storage heater or cooker etc
Domestics: cpcs on a ring final may also be connected to bonding conductors through boilers/water heating equipment - and that will SIGNIFICANTLY reduce the R1R2 value to a falsely low value.
It wont be "absolutely minimal". The people who help to create GN3 would surely agree with what we are all saying here in the comments, at least acknowledge the thought process behind it.
Lights could also have supplementary bonding connected, at the ceiling rose, in older properties bathrooms. Saw that plenty in social housing.
I could see how it may be less significant in industrial, perhaps. But why risk picking up a parallel path when its a simple matter to drop the line and cpc in a wago.
Surely by removing the individual cpc from the Earth bar you have removed all parallel paths for that particular r2 and to promote leaving it in is not as accurate a reading ?
I'll still be testing with them disconnected thanks
Bonding conductors should be removed from the earth bar for these tests but there is no real issue leaving all the final circuits linked together during testing. How would a socket circuit realistically provide a parallel path for a lighting circuit?
You can spend 3 days testing a house removing every socket. What if socket 41 had a missing grommet?
Testing is like all engineering and time is a resource. Spend it reasonably.
I agreed with the viewers post originally and still do now . Parallel paths are normally lower resistance like main bonding etc so give false readings
Couldn't agree more. In most instances, it is nigh on impossible to even get to the earth bar in a commercial distribution board due to the atrocious mess most of them are in. 😮
@@mb-electricalservices Just because something is difficult, isn't an excuse not to do it.
So for example: you have a socket in the kitchen for ignition on a gas hob. The circuit cpc is broken but this isn’t detected as the cpc is finding a path to earth via the gas bond. All good right? Tests perfectly fine!…. Gas works are undertaken and now the incomer is plastic or the bonding is disconnected. Now you have no earth (cpc) and nobody is the wiser. For the sake of undoing a screw instead of using those stupid magnetic links , 5 seconds of effort to undo and you are potentially preventing a dangerous situation. Regardless of what GN3 says I think we should be doing better.
Except you would notice that the reading doesn't match up with zs reading?
For example ze is 0.30
Zs is 0.50
R1 r2 is 1.50...
Then you would know something is up
@@calebbrookes7896this would mean you actually know what your doing 😂 some of these comments make me laugh. Love it when people like your self put a real life situation to these other idiots 👍🏽
@SuperDarren79 if you're at a point of your life where you're doing R1+R2 testing, then you've gotta know what you're talking about.
Tray basket and trunking are exposed conductive parts
ruclips.net/video/SJFGoeqtr04/видео.htmlsi=RNQQDNNvdotwPCB0
Sorry efixx - really disagree here. The real world effect is far from minimal. A cct such as immersion radial could test out fine with parallel paths in place through the pipework, when actually the earth is only being found via bonded pipework.
You're meant to disconnect bonding anyway. Then reconnect before ir testing
Johnny sins is even in electricity 😅
😂😂 brilliant this is the way to deal with someone who calls you out.... i don't disconnect the cpc either unless i get a ready i feel needs looking at....
@mikethemask1525 I don't agree with calling out anyone, I think it is more about learning, and if we can all get something out of it, then it's fantastic. But I fully disagree with the video, and people need to be very careful as they can get caught out .
It's quick and easy to disconnect and put in a wago , so why wouldn't you
Quizzy Bob 😂
Wear and tear on the earth terminal!?!
You're scraping the bottom of the barrel there.
Poor response.
just use magnetic R1+R2 lead
Likelyhood of parlel paths when testing R1+R2 and you removed CPC from. Earting terminal is very very low. Certainly lower considerably than when in the earth bar. Just goest to show how low the standards can be according to regs... just sad.
So ..we don't need to but we might as well gotcha
His sarcastic tones pissing me off
Testing the resistance of the CPC (Circuit Protective Conductor), even with satisfactory results, cannot guarantee that the conductor is continuous and unbroken at all points. The R1+R2 test is often considered inadequate in real-life applications, particularly in industrial settings where each point of the CPC is connected to metal parallel paths (such as metal structures or conduits). While the R1+R2 test may be suitable for domestic installations (like flats), its effectiveness diminishes in industrial plant rooms due to the presence of multiple grounding paths that can lead to misleading results.