Testing for External Earth Fault Loop Impedance (Ze) When You Have a Main Earthing Terminal (MET)
Live testing for external earth fault loop impedance often called the Ze test. This test is demonstrated on a live 3 phase distribution board and will help with AM2, AM2S and AM2E exams. In this video I show you the importance of removing parallel earth paths and how this can be achieved when an installation has a remote MET (main earth terminal).
As always preparing for your end skills test AM2, AM2S or AM2E requires time testing at college and on-site experience of testing electrical circuits.
NOTE- for AM2, AM2S and AM2E you may have a remote main earth terminal (MET) if this is the case this could have the bonding connecting in it (best to check). This will mean the earthing conductor could be removed and tested from this point for the external earth fault loop impedance or you can remove the bonding from the MET and test as shown in this video.
NOTE 2- Your end point assessment AM2 and AM2S will require you to have the main switch locked off, sign in place and key In your pocket during this test 👍🏻.
== 🕐 Time Stamps - Cut to the action 🕕 ==
00:00 - External earth fault loop impedance
00:08 - 3 phase supply and cut out
00:20 - The main earth terminal MET
00:53 - Removing parallel earth paths
01:38 - Overview of a 3 phase supply to a distribution board
03:00 - Disconnecting the Earthing conductor for the MET
03:37 - Testing between L1 and the Earthing conductor
03:47 - Testing between L2 and the Earthing conductor
04:05 - Testing between L3 and the Earthing conductor
04:51 - On site with Matt
05:34 - Turning of MCB's before supply isolation
07:15 - Disconnected Earth conductor
08:06 - Carrying out the external earth fault loop impedance test
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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I do this on a regular basis but still enjoy watching GSH videos when they pop up, takes me back to training days. Nice video Gaz really liked the double approach - drawing and on a working board
Thanks Adrian for still watching 👍🏻
Excellent
If you use a 3 lead setting on the test, is the pefc and pscc both tested in the pfc reading on the megger
4:50 his face on "Sexy" and back to being serious ahahahha
I have had an agreement with previous companies to avoid too much down time in their production, had agreements that their production was closed twice a year, so that we could measure L-PE, and the installations made in the meantime are has been registered with the last measurement for the shutdown. everything is self-consciously done with an agreement between our and the customers' Safety organisations. all measurements at the MET were recorded with my and the customer's signature with time and date.
Great comment. Thanks 👍🏻
I always thought that external Ze measurements were made at the cut out not the consumer unit. Probably has little influence in this case with the 2 being close together but certainly would if the CU was some distance away from the intake e.g a sub main?
What is the specification of The MET you use in this vídeo, please? I'' d like to buy one.
Do you know the brand and supplier of the linked MET please
I personally don’t think they make them anymore 👍🏻. Thanks for commenting and watching
Why did you chose to do this as a 3 lead test wouldn't a 2 lead be more effective losing the the neutral test lead as its a pme anyway?
Does using the 3 lead mean the the pfc is both the pefc and pscc tested ?
Don’t see many of this style earth bar domestic. Only ever seen them on larger scale commercial building
True - I just disconnect the main earthing conductor from the main earthing terminal within the DB consumer unit to test Ze
I'm a subscriber and not getting any of your video's. Strange that 🤔
The installation is off, 3 lead low test without no Rcd's is pointless, waiting around for the rcd to saturate that does not exist , imo 2 lead high test 🙄
The AM2 and AM2S is very likely to have an RCD hence 3 lead test 👍🏻
@@GSHElectricalthe AM2 my have an RCD but this is a origin test so before any sensitive equipment this is high test not 3 lead low imo