3 Lead RCD Test in the Consumer Unit on RCBO's Saving Time During the Live Testing's Process

Student training aid for testing an RCBO rated at 30mA using a MFT Megger tester. Includes a full demonstration of how to test the RCBO using 3 leads from with the consumers unit.

Note my default position is always 3 lead testing as it’s my preferred method of testing for Earth Fault Loop impedance when RCD protection is present. 2 lead tests can also be carried out for both testing RCDs and circuit Impedance.

Student trading aid for testing for external earth fault loop impedance Ze test using a MFT Megger tester. Please note this test is carried out with only the external earth path in circuit. Includes a full demonstration of the test in a domestic single phase installation in the real world.

Student training aid for the live test measuring prospective fault current PFC using a MFT Megger tester. Includes a full demonstration of how to measure PFC current. This test is shown being done out in the real world.

Live tests carried out in the video are...
Safe isolation
Supply polarity
External earth fault loop impedance (Ze)
Prospective short circuit current test PSCC
Prospective earth fault current test PEFC
RCD tests

== 🕐 Time Stamps - Cut to the action 🕕 ==

00:00 - 3 lead RCD test
00:44 - Isolating the board pressing the test buttons on the RCBO's
01:41 - Proving the outgoing side of the consumer unit is isolated
02:46 - Supply polarity
03:52 - External earth fault loop impedance test (Ze)
04:40 - Using a torque screwdriver
05:06 - PFC testing PSSC and PEFC
06:02 - Breaking capacity's of the incoming fuse and the RCBO's
06:16 - Testing the RCBO's form the top of the device
09:22 - Stickers on the front of the consumer unit

Videos are training aids for City and Guilds (C and G) and EAL courses Level 1, 2, 3 plus AM2, AM2S and AM2E.

You can follow me day by day on Facebook, Instagram and Twitter lookout for "GSH Electrical.

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[GSHElectrical]

Live tests carried out in the video are...
Safe isolation
Supply polarity
External earth fault loop impedance (Ze)
Prospective short circuit current test PSCC
Prospective earth fault current test PEFC
RCD tests

[JohnSmith-kbku]

Graham sound like he’s Gaz’ prisoner.

Very well explained. Clear as a bell.

[davidroche]

Great video. Was nice to see other live tests as well as bonus code iformation to keep in mind toward my ongoing learning. and thank you for the suggested advice on RCBO/RCD testing at the board 👍🏻

[mikedavis]

Great video, fair play to Graham. Thanks for showing this kind of content

[michaelcostello]

Great clarity in these videos. Thanks so much. Really interesting. Please keep making them.

[jinxUKBK]

Thanks guys. Doing my inspection soon and this was a great help. Keep it up

[yqflscl]

No need for 3 lead test. 2 lead.. Live and earth is all you need to do. It gives you a free hand to reset trip as well

[LindaTheLearner]

Thanks Graham ... that was really useful 👍

[Clydepatos]

Great video very clear and easy respect for you Gaz

[Mr.Therapist]

I find the video materials to be utterly useful. One thing that would help students all levels is with the terminology and abriviations and acronyms, it's a good thing to use the acronym, but even more useful, if it is mentioned in full at least once so that we would all know what is meant when it's being introduced! Your work is really highly appreciated and most superlatively enjoyed. Thanks señor.

[PlymouthSparky]

Lovely bit of testing lads. Great to see. Yes I see a lot of people missing the supply polarity test. It been some help.

[cj-rbfz]

With the megger tester, you can test Rcds /rcbos with just the 2 leads, in domestic properties I never use the 3 rd lead just keep the 2 leads in unless I’m proving the r1/rn r1/r2 readings on socket then use the plug lead that comes with tester

[zakovbbronchi]

i was told to carry tests on individual tests...thank you for your advice ..

[electricians]

Really useful kit by Kewtech, Lightmate Light Testing Kit, Kewcheck 103 Socket Tester, R2 Socket Test Adaptor,

[johnstewart]

thanks for posting the video to help general awareness of trainee electricians. this video is obviously not meant for the general public who should be getting qualified sparks to do this kind of stuff. just to add a bit of information for apprentices; although guidance note 3 says you can do RCD testing (which includes RCBO's) at the board or a local socket, never any mention of doing it at any other connection point or lighting, an RCD test is effectively a bench test of the device and should not be done with its circuit cables or any other circuit cables under load. the correct way to test RCD's is turn all other circuits off so there is no possibility of currents induced by cables running near each other, remove the load side conductors so there is no load and then test the device, however the EWR says that the full test does not need to be done every time the installation is being inspected if there is a risk the disconnection of conductors could introduce a fault if they are not going to be tested again after re-connection. hence the test at a local socket. so in the video you correctly did the tests with all other circuits isolated and presumably made sure all connected loads were switched off during the testing so no load was present on the RCBO's under test.
I often come across old test schedules where there is only 1 or 2 RCD's protecting all circuits of a board where every circuit has a different RCD results value, this just shows whoever completed the schedule doesn't know what they are doing, if you have 2 RCD's in a modern 17th edition board, all circuits protected by the first RCD will have the same results for 1 x and 5 x column, as will the circuits protected by the 2nd RCD.
doing RCD testing at the board is not only the correct way to do it but as the video shows its also the quickest
just a final comment; the 18th edition has finally realised that users will not test RCD's every three months (and most sparks don't even tell them) so under the 18th edition the notice now says the RCD's RCBO's should be tested every 6 months. we now have the opportunity to associate the changing of summer time and winter time on our clocks etc with the need to test the RCD's. as we all know the reason for users testing RCD's isn't just to confirm that a mechanism designed to save lives works, it is also to lubricate the mechanism so it doesn't get sticky and not work when needed.
all the best to all qualified sparks and please stick to your quotes, don't let punters drive down prices by getting us to compete with each other. we are highly trained professionals and should charge accordingly

[jamiedoble]

As always an informative video for learners!

Any reason in particular you chose a 3 lead test for the RCD testing? Have the same MFT and always use the 2 lead method as it free's up a hand!

[pjvdsandt]

Thanks Grame
Wel done im was in a training room and watch you you test and learning a lesson from you and my Mentor
Thanks thats helps me to mofing on and test on the rigth way out of sans law

[ionutonea]

great video ? please let me know how should be tested the RCBO type B and type C ? thank you !

[Goboholder]

The test aren't they the unfused Megger leads? Shouldn't they be fused leads, for live testing? Thanks for the brilliant videos GSH.

[spark]

Does this work also on Rcd’s found on split load boards? Say putting crocks on neutral and earths and going from lives with probe lead?