LOOP IMPEDANCE & PFC - ASSESSMENT TIPS - PROSPECTIVE FAULT CURRENT ZE PSCC ZS - UNDERSTAND THE TESTS

[@jonathangarstin8682]

Really well explained, unlike many, it is not assumed that you know all fundamental details in case there is a small gap in your knowledge despite many years of installations

[@learnelectrics4402]

Thanks, great comments. Yes, I try and make one video about just one subject at a time and always try and cater for the newbies as well as the experienced. I can remember that I started with almost zero knowledge all those 40 plus years ago. Thanks for watching. Dave.

[@user-qi8tv2sj4m]

I needed this video. Excellent teaching method. Cheers.

[@learnelectrics4402]

Good to know the video has done its job. Thanks. Dave.

[@eurotropia]

You and your videos, man! Wicked!

[@learnelectrics4402]

Thanks for that, appreciated.

[@martmckn]

Thankyou for this training video…… another addition to my mental toolbox …..your videos are really appreciated

[@learnelectrics4402]

Great, thank you. Appreciated. Dave.

[@bizerbalpesh]

Man, a great example to be on you tube...great work and explanation...

[@learnelectrics4402]

I appreciate that, thank you. Dave.

[@A.Y.A]

Wow a great video. Exception, simple and accurate. Thank you. It's really fun and learns to see your videos.

[@learnelectrics4402]

Glad you like them and thank you for watching. Appreciated, Dave.

[@seanakiiki7670]

Surely am learning much from all ur lectures , best regards and God bless

[@learnelectrics4402]

Glad to hear that and thanks for watching, appreciated. Dave.

[@adnanidf94]

Another great video. Really appreciate your hard work in making these videos. It has helped me alot.

[@learnelectrics4402]

Glad to hear it and thanks for watching, appreciated.

[@JC-jv5xw]

At 11:43 you say that the PSCC test lead set up is the same as for PFC, but the diagram correctly shows the sense lead on the neutral.

[@learnelectrics4402]

The test meter setup is the same switch positions but the leads are in different locations. Hope this helps.

[@georgelutu7196]

Thank you for this video. Dankeschön!

[@learnelectrics4402]

You are very welcome.

[@marian-mihaiciobanu1089]

Hello! Where is the additional source electrode (PME) on the TN-C-S drawing...? Thank's for the video!

[@learnelectrics4402]

PME uses the electrode back at the supply transformer. Take a look at this video on earthing systems. Thanks for watching. Dave. kzbin.info/www/bejne/p3LEmWOLpt1spas

[@brilliantproltd9712]

Superb information

[@learnelectrics4402]

Thank you for watching, appreciated.

[@prabaharan-i4r]

Thank you for this video it’s a great explanation ! I just wanted to know, why the overhead power supply can’t provide TN-C earthing arrangement ?

[@learnelectrics4402]

Its whatever method that the supplier uses when installing a supply. We just work with what they give us.

[@gwool4771]

Hi, to measure the PEFC doesn't the main earth need re-terminating to allow for parallel paths before measuring for the PEFC?

[@learnelectrics4402]

Have another look at the video. PEFC is tested once with the earth out, to prove an earth, once with the earth in to take into account any parallel Paths. Hope this helps.

[@jonerasmus9399]

At 5:25 , the Ze test . Must that curcuit be dead before testing . Im confused when you said we are doing a live test. To be clear What is ment by a live test ?

[@learnelectrics4402]

A dead test - no electrical energy in the circuit. Completely dead and tested for dead. Live test, the circuit is energised as it would be for normal use, boiling the kettle, cooking the dinner, etc. Hope this helps. Dave.

[@bizerbalpesh]

May have a video on Industrail equipment/switch cabinet loop impedance testing.

[@learnelectrics4402]

It is now on the list. Thanks for watching. Dave.

[@no_short_circuit]

Thanks again for a clear explnation. For Ze you show (for all types of earthing arrangements) the three wire method for test leads, with one to L, N and E. When measuring PSSC you say that it's "exacly the same test leads and meter set up" but show the blue and black wires from the meter joined together on the N conductor. That is the correct configuration for measuring PSSC?

[@learnelectrics4402]

Correct. The measurement is between Line and Neutral, so the black earth lead is is on the neutral. but the meter needs the neutral connection, so we put the blue neutral lead there too. Have another look at the video, it is explained. Thanks. Dave.

[@pietnel6077]

Do we also test pscc between phases on a 3 phase system? This current can be way more than pscc between L and N. Will the CB be able to handle this short circuit current?

[@learnelectrics4402]

We can m measure PSCC between L & N but most test meters will not measure between phases as they are not designed for 400V. We choose the worst case PSCC from the single phase testing and multiply by 2. We use this as the prospective 3 phase short circuit current. have a look at Appendix 14 page 554. Dave.

[@babyprince84uk]

I cannot thank you enough for these wonderful videos. I was wondering. Why Ze must be a live test? Why difference it will make if we test it without electricity? Is it because we have transformer which has windings coil that is inductive resistance?

[@learnelectrics4402]

You cannot test Ze as a dead test without turning off everybody else electricity in the town. Its a live test back to the suppliers transformer, This video will help. kzbin.info/www/bejne/rqWnepdjnJx6oLc

[@bonnywail]

If we have a Line and neutral conductor back to the transformer then why not convert TT systems to TNC-S arrangements throughout. We need a line and neutral from Source to dwellings anyways so we already have a complete circuit from supply!! I'm guessing it's not that easy as it would have been done already..It makes me wonder sometimes tho considering how unstable TT systems can be under some circumstances..

[@Hff19927]

Id assume it’s because tns and tncs are bonded to star point through MET. It doubt it would be feasible to have a single earthing terminal for a property going back to the transformer thus the need to earth it seperately.

[@learnelectrics4402]

The TNS and TNCS cables are of different construction. If they are retro-fitted as overhead cables, the weight can be quite substantial. Good question.

[@learnelectrics4402]

Thanks for taking part Daniel, appreciate the input. Dave.

[@arayated5608]

Well come mate.

[@learnelectrics4402]

Glad it was useful, thanks.

[@nittaberi]

I believe, that Zs not only the Eart Fault Impedance. I think, that the Line-Neutral loop impedance is also called Zs. The Prospective Fault Current (PFC), and the Prospective Short Current (PSC) is also depends on system loop impedance (Zs). Do I see well? Thank you for your very useful work! 👍

[@learnelectrics4402]

No, Zs is a line to earth fault. Between line and neutral it is a short circuit. Have another look at the video. Thanks for watching. Dave.

[@ovidiuroman1979]

thank you

[@learnelectrics4402]

Very welcome. Dave.

[@Roq-stone]

I doubt it could be made much clearer.

[@learnelectrics4402]

Very nice reply, thank you. Dave.

[@babyprince84uk]

I’m slightly confused. Why do we need to do PFC? That is the purpose. Thanks for the fantastic video!

[@learnelectrics4402]

Its one of the essential tests and helps us ensure that the devices can handle the fault current.

[@babyprince84uk]

@@learnelectrics4402 thank you But I don’t understand which part of the breaker will this help with? I know we need the short circuit part. But I’m now aware of any scenario where we can practically use PFC to choose breakers or anything else