External Earth Fault Loop Impedance Ze Test - How to Remove Parallel Earth Paths - Live Testing

In this video me and Marcus show how to carryout an external earth fault loop impedance test on a single phase installation. All stage of this live test are demonstrated as well as the importance of removing parallel earth path created by incoming metal pipework such as the water and gas. This video is designed to help learners with testing and fault finding units in City and Guilds and EAL qualifications as well as AM2, AM2S and AM2E end point assessments for apprentice electricians.

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

00:00 - External earth fault loop impedance test
00:20 - Isolate the consumer unit
00:48 - Remove parallel earth paths
01:05 - Incoming water or gas could be metal
01:33 - Supply earth
01:42 - Remove the earthing conductor
01:50 - Alternatively you can remove from the MET in this case
02:12 - All out going circuit off during the test
02:48 - Top of the double pole switch is now live
03:01 - Setting up the Megger MFT
04:09 - Carrying out the Ze test
04:53 - Comments on existing installation

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

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[Dog-whisperer]

Great video.
Nice and simple, with clear and easy to understand explanation.
Fantastic video guy’s 👍👍👍❤️

[detroutspinners]

Great video, your content is so helpful for apprentices like me. Quick question, how would you perform this test on a sub main? Just R1 + R2 of the live and CPC going between both boards, and record it as Zdb?

[edrobens]

During this test all short circuit protection between you and the local transformer has been removed apart from 100A incoming fuse, so do a risk assessment first. In reality the fuse/dist board may be in an inaccessible, unlit location or you may have to work from steps/platform. The double pole isolation switch may be in a different location and DURING SET UP this should be padlocked OFF.

[yanalnaghawai]

Many thanks for the great videos, , , what is the maximum for T.T ??

[Badger]

any chance you can do some testing videos with a Fluke 1664fc? Ive bought one and maybe i made a mistake and should have bought a, megger. I cant find many videos using a fluke

[mounirdiab]

Great content as always, what's the purpose of measuring Ze and Zs and what's the interpretation and remedial of a high reading of Ze or Zs.

[laganas]

Hi, is this one of the tests that you have to take when doing the level 2 diploma in electrical installations? Or is this for the level 3 diploma? Thanks.

[Hussain-wk]

So, I'm guessing if we didn't have that external double pole switch we would energize the installation from the main switch in the CU

[SeanyyBoy_]

How have you mimicked a TN-C-S without creating a N to PE fault?

[astonpowers]

Hi where would I record this result on a test sheet

[BigPoppa]

Why wouldn’t the Ze be taken from the external double pole switch? I understand if it’s for the purpose of the video to show how it would be undertaken from inside the CU. But surely in this scenario a Ze would be taken from the external DP switch and then a Zdb from the CU.

[obinnakalu]

Hello Admin @GSH electrical. Please I need your assistance with a power supply problem.
1. Please what are the causes of negative power factor registered on a MD meter for a distribution installation.
2. How can this be corrected.

[dansheppard]

Sorry if this is a dumb question, but why is it higher for TN-S than TN-C-S? I understand the difference between the earthing methods, I'm just not twigging why that might lead to a higher impedance being acceptable for TN-S.

[Jim]

I still don’t get why the breakers have to be off. I know he mentions “It wouldn’t have that earth fault loop path” but you have the main switch off so I don’t see the reason behind it.

[asp]

37seconds....There is only 1 MET and it is not the earth bar within the consumer unit. It is the external earth bar in this case

[callumsimpson]

Iv never seen insulation in the off position 🤣🤣