LIVE Testing on a 3 Phase Dis-Board - External Earth Fault Loop Impedance Ze, PEFC, PSCC AM2 & AM2S

Live testing for external earth fault loop impedance, prospective earth fault current PEFC and prospective short circuit current PSCC (PFC tests). These tests are demonstrated on a live 3 phase distribution board and will help with AM2 and AM2S exams. We use the rule of thumb for calculating the PSCC test by taking the highest reading form the line and neutral tests and doubling it and then we go on to show you how some instruments can measure PSCC between line conductors. 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 etc you may have a remote main earth terminal (MET) if the 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 - Ze and PFC tests
00:54 - Isolating the 3 phase distribution board
01:58 - Disconnecting the earthing conductor to remove parallel earth paths created by the bonding
02:55 - External earth fault loop impedance test Ze test on a 3 phase dis-board
05:11 - Reconnect the earthing conductor
05:19 - Prospective earth fault current PEFC test (PFC)
06:34 - Prospective short circuit current PSCC test (PFC)
08:00 - Rule of thumb double your highest reading from PSCC test for a 3 phase supply
09:48 - Testing PSCC between the 3 line conductors of a 3 phase supply

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, Twitter and TikTok lookout for "GSH Electrical”.

#GSHElectrical #Electricaltrainingvideos #electricaltesting #am2

[TheJordaneh]

Not sure if you guys will see this but just wanted to say a massive thank you, passed my AM2 first time and your videos absolutely carried me through, thank you!!!

[callumsimpson]

My level 3 teacher is currently drilling me with three phase testing and fault finding as Iv handed my design project in well early. I’m so glad because once you start doing the three phase it’s so much different. I can honestly say I feel confident to do my 2391 and am2 and watching these videos now make a lot more sense than when I watched it without doing three phase.

[jonathanrose]

Great video!
Lots of real world training missing online.
H&S… I wear VDE gloves when working/testing live. Just mitigates the risk. Easy enough to fall forward on to the live terminals, especially so on older 3ph boards & working off a ladder, etc..

[GSHElectrical]

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

00:00 - Ze and PFC tests
00:54 - Isolating the 3 phase distribution board
01:58 - Disconnecting the earthing conductor to remove parallel earth paths created by the bonding
02:55 - External earth fault loop impedance test Ze test on a 3 phase dis-board
05:11 - Reconnect the earthing conductor
05:19 - Prospective earth fault current PEFC test (PFC)
06:34 - Prospective short circuit current PSCC test (PFC)
08:00 - Rule of thumb double your highest reading from PSCC test for a 3 phase supply
09:48 - Testing PSCC between the 3 line conductors of a 3 phase supply

[marcusleung]

the best demostration i found on YT so far , Cheers

[EricTheHiking]

Thank you guys for all test. Some of them I wasn't sure 👍👍👍

[Big-T-]

Thanks very much, been looking for a good ze, pfc vid in a 3p DB. Getting ready for my fica at the end of this year👍🏾.

[JohnCanty]

Thanks guys make it so much easier to understand seeing it 👍🏼

[peterjesus]

It was more than helpful, God bless u

[Bari_Khan_CEng_CMarEng]

Another great video and demonstration, much appreciated

[kilowatt]

Excellent Video! Very well explained. I have just one question please to clear my mind. In theory, line to line fault is 3phase fault multiply by 0.866, therefore can I just use the fault current measured in L-L (4.11 kA) divided by 0.866 to get the 3phase fault instead of doubling the max fault measured in L-N?

[ollieb]

Great video guys! Not sure how strict and to the book the assessors will be in the am2 but GN3 does recommend dividing the line to line value by 0.87 if measuring Ipf between phases.

Edit:
After some research online I believe this figure is a guide to working out a simultaneous fault between all phase conductors with a fault of negligible impedance.

[jonerasmus]

Plz do many more videos. Great job chaps

[Mok-li]

Thanks, you make it easy to understand

[dimitrisblane]

Thank you so much for these videos. Really helpful information!
One question. Why we take the PFC measurement with the main switch off and on the source side? When using the system all breakers etc are on. Why take the rest of the system out of the equation? the PFC surely would be different when the whole system is connected and turned on?

Thank you

[redroutemaster]

Good video, informative.
After 29 years of data cabling/engineering a flooded market of poor quality engineers the last few years reducing rates I started an electrical training course a month ago and enjoying it (should of started years back).

Would the incomer earth be better with a ring crimped connector?

[dominicboyle]

Great Video Guys, very well explained

[krishtheobald]

I do believe the highest L-L reading has to be divided by 0.87 to get a simultaneous 3 phase fault PSCC.

Someone else also mentioned this. Was there a reason you didn’t mention it in this video?

[dooz]

Great video, possible to do video on 3 phase rcd 300mA

[kingofthetrowel]

Sorry if this is silly question as I’m still a beginner adult learner etc but why do we have to use a, , 3lead high or 3lead low? what’s difference and why do it etc 👍👍