I always test with them installed as because depending on the circuit I've found that you get different readings with the loads connected. You only need to remove lamps and loading accessories when IR testing
Perhaps I’m a bit behind the times, so please help to educate an old fool. I would do a Zs reading at the end of line. Then, I would do the RCD test also at the end of line, to check that at the end of line, the time is still within limits. I would do this with all loads connected, as would be in the final installation as utilised by the end user who may be experiencing an Earth fault on that circuit at the furthest point. Please explain why you do it at the RCBO with all loads disconnected. Is there a reg you could quote in BS7671. Many thanks for the demo and a reply would be greatly appreciated. Note: if the answer is just because you are testing the RCBO device and not the circuit, then can you please comment if my method is industry preferred “best practice”, or should I only be concerned with testing the device, regardless of the circuit it is intended to protect, which is as per your method demonstrated in this video. Example: if measured at the RCBO the time at 5x was 32ms but at the end of line was 38ms, I would record 38 on the test sheet as the slower time. Is this technically correct, or good or bad practice, or just plain wrong? Thanks.
I may have possibly partly answered my own question. I guess some loads may leak a small amount of residual current, so when testing a 30mA RCD, with a load on that circuit of 10mA, there’s actually a 40mA imbalance during the test, which would not be a true test. But still curious why you wouldn’t do this at the end of line.
@@sam04019491 i believe it should be tested with a load, if it didn't trip with the load connected in question then it could be that the protective device is not suitable🤔
Hi Gary great video as usual . Just want to add one comment and that is you should disconnect the Neutral fly lead also for the particular RCBO under test.before you proceed with the testing.
This gives us an Isolated disconnection time purely related to the actual RCD device without testing the circuit it protects Are we only testing the RCD or the whole circuit?
You’re only wanting to introduce that test current to purely test the device, should a fault occur during circuit operation, you’ve verified that the device will operate. Hope that makes sense.
My Robin KTS 1620 kept tripping the RCBO as soon as i connected the probe to the 230 volts . I needed to connect the live and neutral probes to the outlet of the RCBO for this convenient test to work with the earth probe on earth terminal..
I know it is a 'should not be' to have 2 RCDs in series... (due to the nuisance) but when it DOES occur, say on EICR's... a tip to test ONLY the one local to you, to get readings for THAT device... use the Neutral INCOMING to the device as the earth... tests the imbalance in the same way :) (then of course note as a c3 or potential c2 if it kills safety critical circuits)
Why do you have to remove the loads? I often rcd from a nearby accessory. If it passes I'm happy. I don't care about absolute results. Seems to be a counter insentive to disconnect all loads for testing.
Because you get false readings. every load has some form of residual current leakage. this can be up to 10-20mA on a whole circuit. If you then test with loads connected it will trip at the current the tester introduces in the circuit+whatever is leaking in the circuit. If you tester then shows it shut off at 30mA, great it passed. But it might have been 50mA if you count your loads. you still have no idea what the tripping current is though.
Are you not now expected to test rcds on load now due to the risk of dc load saturating the coil?? I have heard this but if you could confirm that would be great
Never tested like this, in real life there’s no time and sometimes they don’t even let us disconnect the cables from any breakers. Load on, test and go. Tested thousands and never had any problems.
I'm going to start an electrical installation course soon and trying to get a head start but no idea where to start, any recommendations on a video or playlist of yours to watch?
Lighting Circuits 1 Way, 2 way and Intermediate & Testing ruclips.net/p/PL2Ea5r9gxUUcToR4p1wN8QDZ2NR_z2gCh I always recommend this playlist start at the top and work your way down 👍🏻
Isn’t this just the same as pressing the test button, the real test would be performing it at the furthest point of the circuit. To get the highest(slowest) disconnection time… 🥺
@jamiekent1970 pushing the test button puts a much higher current across it than I delta n. It doesn't prove the device will open at the rated current. Standard is to test on the load side at the device
On the AM2S rig you will have secured isolation before this and you only have one RCBO for the sockets and that circuit will have nothing plugged in… so test from the top of the RCBO with it in the off position. 👍🏻
Ok. But what you may not be testing at rated current. Your testing plus whatevers leaking on the circuit which is variable... So you're not doing the test right. The correct test is off load at rated I delta n. At 0 and 180. Concern about loads stalling the device is a selection issue and should have been considerer prior.
@@paulsidebyrne sodit... Skip to the end. Have a search for 'iet testing rcds off load' you'll find an article by Mark coles.' You're welcome... You can now start doing it properly. Must be brilliant being so sure of yourself. 🤣
You're testing tripping times ? Shouldn't you be testing at the farthest point in the circuit? If the time exceeds the specified limit, then that circuit doesn't comply with BS7671 ?
@@GSHElectrical We always test at the device like you do, but then an additional ramp test with loads connected to get a real world feel for any potential nuisance tripping (I know that's not a required test but saves 'it worked before you put that thing in' call backs :)
..... what if the load is the fault ..... fault on the wires you have just disconnected ie a leakage into or out of those wires that you have just disconnected , that create a bypass , short , leakage , failure , over supply into , out of and the RCD doesn't trip soon enough , Quick enough.... voltage jump upon amperage rise , You have disconnected wires You have changed the status of that system It's ok I've disconnected a power supply I didn't know about and everything tests fine who says those aren't supplying a source under certain conditions Who says there isn't two switches , load feeds Test trip in place Test components of the circuit Close test the full circuit Ahhh but if cow's fly over the moon , Jack's beans grow to create another bean stalk Smile as you get electrocuted . Electrons take the shortest path They only want to get there Smile as you get electrocuted .
Wrong 🤣 he is testing if the rcd trips within specified times, 1x less than 300ms, 5x less than 40ms... If it fails replace rcbo, however you can test with loads connected so i dont understand why he removed the final circuit...
@@Seth-vv1gu Because you want to test the RCD functionality, not RCD functionality plus possible leakage current from connected appliances. That would also falsify the tripping current reading. And tripping time for 1x is less than 200ms 😉
@@Seth-vv1gu Here in Germany in a TT-system it's 200ms, in a TN the VDE even permits 400ms. The 300ms are only relevant for the manufacturer of the RCDs, except the British regs state that 300ms too.
because it shouldnt need to be under load as you only need to check the rcd, all your other tests should find any potential faults on the circuit, if any
@@Seth-vv1gu If you test a circuit that's got a bunch of leakage on it it might get artificially faster trip times? In the extreme, say you've got a faulty RCD protecting a faulty circuit. There's 50mA of leakage but the RCD hasn't tripped. You don't disconnect the circuit, test the RCD, it trips at 75mA, your tester thinks "great, I applied 25mA and it tripped in a sensible time, all good". In reality, at the specified 30mA the RCD might not trip or might not trip in the required time.
Ahhh okay dude, so disconnecting loads will remove the earth leakage so you get a true test of the rcbo or RCD... So even when you do an auto RCD test the earth leakage can still give you an artificial reading ?
@@Seth-vv1gu I'm only guessing that's why, that and not wanting to confuse a load of electrical goods turning on and off rapidly for a few minutes. The "On site guide" says "The tests are made on the load side of the RCD, as near as practicable to its point of installation and between the line conductor and the associated circuit protective conductor. The load supplied should be disconnected during the test." You can always have a bit of leakage from a circuit which can bias results. The other way of looking at it would be if you've got 10mA of leakage on the circuit then your RCD would artificially fail the 1/2 times test even if there might be nothing wrong with it. 10mA of leakage plus 15mA from an RCD test would put you right in the area at which you'd expect it to trip.
I always test with them installed as because depending on the circuit I've found that you get different readings with the loads connected.
You only need to remove lamps and loading accessories when IR testing
GN3 states the load should be disconnected during the testing of the RCD
Gotta love the R2-D2 TEST
Bleep Bleep
Thank you so much indeed Gary, you made electricity testing and inspection very easy.
Thanks for the support and watching 👍🏻
Thanks for sharing these ☺️
Great tip Gary, thanks for sharing.👍🏼
Always test at most convenient place
Gary you the guru of sparking
Great video. This is another top tip. It always deepens our understanding by knowing different ways of achieving the same thing.
Perhaps I’m a bit behind the times, so please help to educate an old fool.
I would do a Zs reading at the end of line. Then, I would do the RCD test also at the end of line, to check that at the end of line, the time is still within limits. I would do this with all loads connected, as would be in the final installation as utilised by the end user who may be experiencing an Earth fault on that circuit at the furthest point. Please explain why you do it at the RCBO with all loads disconnected. Is there a reg you could quote in BS7671. Many thanks for the demo and a reply would be greatly appreciated.
Note: if the answer is just because you are testing the RCBO device and not the circuit, then can you please comment if my method is industry preferred “best practice”, or should I only be concerned with testing the device, regardless of the circuit it is intended to protect, which is as per your method demonstrated in this video.
Example: if measured at the RCBO the time at 5x was 32ms but at the end of line was 38ms, I would record 38 on the test sheet as the slower time. Is this technically correct, or good or bad practice, or just plain wrong? Thanks.
I may have possibly partly answered my own question. I guess some loads may leak a small amount of residual current, so when testing a 30mA RCD, with a load on that circuit of 10mA, there’s actually a 40mA imbalance during the test, which would not be a true test. But still curious why you wouldn’t do this at the end of line.
@@sam04019491 i believe it should be tested with a load, if it didn't trip with the load connected in question then it could be that the protective device is not suitable🤔
Should be testing RCD with no loads connected for the reason you gave in your reply to yourself.
You can do it anywhere in the circuit you like as long as there are no loads it’s the same test with the same result
If the trip time was 32 ms at the rcbo it will be 32ms ANYWHERE along the circuit.
Lovely! I guess safe isolation took place at the start and the cables were reinstated with the right torque setting. Of course it was! It’s GSH.
100% only had 60 seconds to offer the information in the short format 👍🏻
very nice
Hi Gary great video as usual . Just want to add one comment and that is you should disconnect the Neutral fly lead also for the particular RCBO under test.before you proceed with the testing.
Just curious why?
If you disconnect the incoming neutral what are you testing?
@@charliedecker7702 he's on about the flylead, not the incoming neutral. Still don't get why.
@@charliedecker7702 All loads disconnected is whats required
@@XeonXR6 the flylead is connected to the incoming neutral.
Thanks for sharing
Always done it this way 👍
Perfect
This gives us an Isolated disconnection time purely related to the actual RCD device without testing the circuit it protects
Are we only testing the RCD or the whole circuit?
In this case, the test is undertaken to prove that it will function within the correct time given an applied current of the rated device :)
You’re only wanting to introduce that test current to purely test the device, should a fault occur during circuit operation, you’ve verified that the device will operate. Hope that makes sense.
Yes true. I think best practice would be tripping from GPOs then tripping lighting/ac/boiler circuits at the switchboard
My Robin KTS 1620 kept tripping the RCBO as soon as i connected the probe to the 230 volts . I needed to connect the live and neutral probes to the outlet of the RCBO for this convenient test to work with the earth probe on earth terminal..
Great video ... Quick answer to robo testing 👍
I know it is a 'should not be' to have 2 RCDs in series... (due to the nuisance) but when it DOES occur, say on EICR's... a tip to test ONLY the one local to you, to get readings for THAT device... use the Neutral INCOMING to the device as the earth... tests the imbalance in the same way :) (then of course note as a c3 or potential c2 if it kills safety critical circuits)
Why do you have to remove the loads? I often rcd from a nearby accessory. If it passes I'm happy. I don't care about absolute results. Seems to be a counter insentive to disconnect all loads for testing.
Because you get false readings. every load has some form of residual current leakage. this can be up to 10-20mA on a whole circuit. If you then test with loads connected it will trip at the current the tester introduces in the circuit+whatever is leaking in the circuit. If you tester then shows it shut off at 30mA, great it passed. But it might have been 50mA if you count your loads.
you still have no idea what the tripping current is though.
You are only testing the rcbo and not the overall installation in conjunction with the relevant rcbo.
Thats what Zs, R1+R2, End to end and IR testing does though
GN3 states the load should be disconnected when testing an RCD
Are you not now expected to test rcds on load now due to the risk of dc load saturating the coil??
I have heard this but if you could confirm that would be great
Do you also test Earth loop impedance?
From Germany, I know exact the same breakers from Siemens
HOLY CRAP!! Game changer!!!
Never tested like this, in real life there’s no time and sometimes they don’t even let us disconnect the cables from any breakers. Load on, test and go. Tested thousands and never had any problems.
I'm going to start an electrical installation course soon and trying to get a head start but no idea where to start, any recommendations on a video or playlist of yours to watch?
Look at GSH’s, John ward and other electrical install videos they contain loads of information
Lighting Circuits 1 Way, 2 way and Intermediate & Testing ruclips.net/p/PL2Ea5r9gxUUcToR4p1wN8QDZ2NR_z2gCh
I always recommend this playlist start at the top and work your way down 👍🏻
Wait could i do this in my 2391 exam..or will be marked down for it?
Well it's in guidance note 3 mate so I think they'd be going some to mark you down
Isn’t this just the same as pressing the test button, the real test would be performing it at the furthest point of the circuit. To get the highest(slowest) disconnection time… 🥺
No
@@reeceoverton1421 then explain cleaver clogs 🧐🤣
@jamiekent1970 pushing the test button puts a much higher current across it than I delta n. It doesn't prove the device will open at the rated current. Standard is to test on the load side at the device
I have my AM2S very shortly, if I was to test using this method, is it not a failure of safe isolation?
On the AM2S rig you will have secured isolation before this and you only have one RCBO for the sockets and that circuit will have nothing plugged in… so test from the top of the RCBO with it in the off position. 👍🏻
@@GSHElectrical does this mean we can test at the top of the RCBO without disconecting the load cables?
@@GSHElectrical how can you energise the RCBO in order to carry out the RCD test if the main switch is locked off? Or have I misunderstood?
I got a question bro. Will you answer
Na never do this always do rcbo or rcd under load I don't think this is a tip I think it's stupid
Ok. But what you may not be testing at rated current. Your testing plus whatevers leaking on the circuit which is variable... So you're not doing the test right. The correct test is off load at rated I delta n. At 0 and 180. Concern about loads stalling the device is a selection issue and should have been considerer prior.
@travoltasbiplane1551 mate you have no idea what your on about with an answer like that
@@paulsidebyrne 🤣 ok mate. I beg to differ. What exactly did you take issue with...
@@paulsidebyrne sodit... Skip to the end. Have a search for 'iet testing rcds off load' you'll find an article by Mark coles.' You're welcome... You can now start doing it properly. Must be brilliant being so sure of yourself. 🤣
@@paulsidebyrne no? How about guidance note 3? It's in there too. Or do you not want to play anymore?
You're testing tripping times ? Shouldn't you be testing at the farthest point in the circuit? If the time exceeds the specified limit, then that circuit doesn't comply with BS7671 ?
Hi it’s an RCD test not an earth fault loop impedance 👍🏻
@@GSHElectrical We always test at the device like you do, but then an additional ramp test with loads connected to get a real world feel for any potential nuisance tripping (I know that's not a required test but saves 'it worked before you put that thing in' call backs :)
@@GSHElectrical so your testing parts of the circuit separately (RCD then FL) and not as a complete apparatus. Seems strange.
Why take out the cables...not sure why the necessity to do this
Would you still do it this way if it was a MCB not a RCBO protecting the the circuit?
Gary your misses says hi
Thanks Liam hope she is well 🤣
Interesting use of a ferrule on the earthing conductor but not the neutral fly leads where is arguably more necessary. God im sad 🤣
The neutrals are sonic welded 👍🏻
So many 'sparkys' in this comment section need to get themselves GN3.
That's a ramp test, what's new
..... what if the load is the fault
..... fault on the wires you have just disconnected ie a leakage into or out of those wires that you have just disconnected , that create a bypass , short , leakage , failure , over supply into , out of and the RCD doesn't trip soon enough , Quick enough.... voltage jump upon amperage rise ,
You have disconnected wires
You have changed the status of that system
It's ok I've disconnected a power supply I didn't know about and everything tests fine who says those aren't supplying a source under certain conditions
Who says there isn't two switches , load feeds
Test trip in place
Test components of the circuit
Close test the full circuit
Ahhh but if cow's fly over the moon , Jack's beans grow to create another bean stalk
Smile as you get electrocuted .
Electrons take the shortest path
They only want to get there
Smile as you get electrocuted .
Time to cut down on the crack pal.
Thanks for sharing Gary. So I assume if it failed for any reason, you would then go to the lamp fittings to see what is happening?
Wrong 🤣 he is testing if the rcd trips within specified times, 1x less than 300ms, 5x less than 40ms... If it fails replace rcbo, however you can test with loads connected so i dont understand why he removed the final circuit...
@@Seth-vv1gu Because you want to test the RCD functionality, not RCD functionality plus possible leakage current from connected appliances. That would also falsify the tripping current reading.
And tripping time for 1x is less than 200ms 😉
@@Marcel_Germann you are wrong about the tripping times dude deffo 300ms 😂😂😂
@@Seth-vv1gu Here in Germany in a TT-system it's 200ms, in a TN the VDE even permits 400ms.
The 300ms are only relevant for the manufacturer of the RCDs, except the British regs state that 300ms too.
Do what my granddad used to do , lick his fingers and grab the wires.
Why are u testing unloaded??
because it shouldnt need to be under load as you only need to check the rcd, all your other tests should find any potential faults on the circuit, if any
I know i dont get why the load of the rcbo was disconnected, ive tested numerous rcbo's with loads connected and they test fine...
@@Seth-vv1gu If you test a circuit that's got a bunch of leakage on it it might get artificially faster trip times?
In the extreme, say you've got a faulty RCD protecting a faulty circuit. There's 50mA of leakage but the RCD hasn't tripped. You don't disconnect the circuit, test the RCD, it trips at 75mA, your tester thinks "great, I applied 25mA and it tripped in a sensible time, all good".
In reality, at the specified 30mA the RCD might not trip or might not trip in the required time.
Ahhh okay dude, so disconnecting loads will remove the earth leakage so you get a true test of the rcbo or RCD... So even when you do an auto RCD test the earth leakage can still give you an artificial reading ?
@@Seth-vv1gu I'm only guessing that's why, that and not wanting to confuse a load of electrical goods turning on and off rapidly for a few minutes.
The "On site guide" says "The tests are made on the load side of the RCD, as near as practicable to its point of installation and between the line conductor and the associated circuit protective conductor. The load supplied should be disconnected during the test."
You can always have a bit of leakage from a circuit which can bias results. The other way of looking at it would be if you've got 10mA of leakage on the circuit then your RCD would artificially fail the 1/2 times test even if there might be nothing wrong with it. 10mA of leakage plus 15mA from an RCD test would put you right in the area at which you'd expect it to trip.
We do it better in the USA
I disagree with this method.
And that’s what we like about social media 👍🏻
@@GSHElectrical you like I'll informed opinion?
Do you also disagree with GN3?