External Earth Fault Loop Impedance on a TN-C-S Earthing Arrangement Measuring Ze in Ohms (max 0.35)

[@monehselik6185]

Learned more from this channel than any of my tradesmen. Thanks lads 👍🏻

[@yoyoyotooo]

Your videos are the best explained on you tube!👍👍

[@GSHElectrical]

Thanks 👍

[@garethgordon9141]

Well explained and clear as usual, thanks 👍🏻

[@liamcollins8692]

I am subscribing to your channel, this was very well said.

[@GSHElectrical]

Massive thanks 🦾

[@liamcollins8692]

@@GSHElectrical Hi mate, I've just been playing around with my megger. Question - what is the difference between the high current loop impedance test and the low one? I don't see why we wouldn't always use the low current one to avoid tripping switchgear.

[@raypooley1312]

Hi. It has been a while since you posted this video so I hope it's not inappropriate to pose a question. That's a nice bit of kit you have there for measuring Ze. But if you didn't have that you could just use an appropriate multi (say, 200 - 600 amps AC) and measure the current (i) when you bridge the line with the earth and calculate the impedance from that ie: 230/i. Is there any reason why that approach wouldn't work or give you an accurate reading for Ze? Thanks.

[@marcopetrillo6867]

I would be interested to know the answer to this question too

[@seandempsey7351]

Hi Gaz just wondering why you are doing a Ze test with just the red and green test leads ? According to the the instructions for my Robin KTS 1620 the black and green test lead are connected to the 16mm earth and as it is connected to the the neutral so you are testing both, and my kewtech Kt 63 instructions say that for a two lead high the blue lead is pgybacked of the green. So shouldn’t you have your three leads in the two lead configuration as the earth and neutral for TNC-S as connected together from the head back to the transformer. Or is that mega have there MFTs already configured internally?

[@pah9844]

Hi. You have said the parallel paths of the water, gas etc have been removed to give a true reading. Do you mean you have disconnected them?

[@Shawn-gw7ns]

Great videos, really helpful and clear!

[@mainlineelectronics5266]

Where in Bs7671 does it say about 0.35 is the maximum Ze ?.

[@jeremykemp3782]

Do you not have to add the R1 and R2 to this value also?

[@leemckerrow1986]

Question! What would you have to do if the impedence was over 0.35 ohm?

[@GSHElectrical]

Contact the network operator 👍🏻

[@RageQuitter1]

What if your db supply is swa? Do you disconnect the gland as well to eliminate parallel paths?

[@IAmThe_RA]

Is this test necessary in a TT system?

[@GSHElectrical]

How would you know you had a connection to earth if you didn’t test it..?

[@IAmThe_RA]

@@GSHElectrical From your experience if the earth electrode has a resistance to earth lower than 1Ω (which is required in my area) what is the expected value of the external earth fault loop impedance?

[@nelfrancis-b.206]

When do we turn the selector switch of the Megger to Zmax?

[@thomasleathley9681]

how come you didn't lock off the main switch?

[@seandempsey9396]

How do you do this with the ROBIN kts 1620 OR the kewtech kt62 multifunction testers thank you.

[@seandempsey9396]

Any help would be much appreciated

[@reececooper4974]

Hi Gaz, love the content mate, I’m currently about to do my am2, do you have to do a two or three lead Ze test? I’ve been told two different things, many thanks again mate

[@GSHElectrical]

Hi, thanks for commenting, I am currently working on AM2 content for the coming 12 months sadly to late for you. All the best with you pending assessment. kzbin.info/aero/PL2Ea5r9gxUUdVgYrSiQG7RQDBOcUWjCcX Thanks Gaz

[@reececooper4974]

GSH Electrical cheers for the reply, I’ve sat my am2 and passed so happy days!!👌🏻

[@waynesparrow2015]

@@GSHElectrical I did my Electrical Domestic Installers Package - doesn't make me a Sparks and I was retraining after being made redundant - haven't done any Sparks for yonks but these video's are the best!!! - thanks for the link to all the training videos you have done to date - appreciate the content and professionalism - I was offshore for 20 and and some sea time before that - where do I go from here??? Will keep watching your video's and see if it's worth me doing the 18th Edition and some shadowing with a real Sparks - CHEERS !!! Any advice appreciated - live in HERTS :-) COURSE COMPLETED AND PASSED • 4 day Electrical Foundation Course • 5 day Domestic Installers Course including C&G 2393 Building Regulations Qualification • 3 day 17th Edition C&G 2382-15 Qualification • 4 day Inspection and Testing 2392 Qualification

[@Ethan_Rogers11]

@@reececooper4974 taking my am2 test soon, do you have any tips for it? Thanks

[@reececooper4974]

@@Ethan_Rogers11 main thing is too read through the spec a few times, make sure you know what cables to use where and then just try and stay calm👌🏻just don’t think you’ve got loads of time because it comes round quick! You should be fine though brother! Go smash it!!🔥

[@davidcohen5982]

Hi. Could you please explain the test you performed? What do you mean by EXTERNAL loop impedance testing? What are you testing actually??

[@jamblob3208]

I believe this is Zs = Ze + (R1 + R2) which requires a complicated external test to be made. Complicated because that live wire to earth does not want to go through any instrument that is not designed for the full voltage that comes into the domestic installation in a large wire. Ze is what resistance there is to actual supply earth. This is mega ohms inside your installation hopefully because you never join earth to live. But in fact it is very low resistance if you accidentally did this and needs to be so externally also. In TT it still needs to be 21 ohms, very high compared to 0.35ohms but still a path for current to go instead of the human body.

[@Dipen1984]

Isn't that reading for PEFC?

[@MrBradleya16]

How do you get Zs at db for a 3 phase board?

[@Jack-xh4rj]

You do exactly the same here but as it is a 3 phase we have 3 lines L1, L2 and L3 So you would test E to L1, E to L2, E to L3 and record the highest Hope this helps

[@JustARandomSomething]

When would you use the L-N test?

[@ethansellwood7343]

I think you would use that when doing your PSCC test

[@MaxEpsom]

My Ze is 0.12 for TN-S is it acceptable!!

[@GSHElectrical]

Yes - max 0.8 ohms

[@seandempsey7351]

How can 0.12 for TN-S be acceptable if the maximum is 0.8 ?

[@kss987]

@@seandempsey7351 0.80 it means

[@jeffdavies9112]

Why would you not prove dead at point of the work once you had isolated and opened the consumer unit ? I the video was not about this requirement, however as it is designed to teach others, it would have been good to have shown the discipline in my view.

[@UndisputedChamp834]

Wouldn't you check for dead with your 2 pole on the outgoing side of the main switch just as a precaution before you go messing around inside the FB just to confirm the main switch has done its job and killed the board. Well I would anyway, not saying you did anything wrong just an observation really

[@poulzinevic2951]

10 Stars o/

[@padraicfaherty8433]

12v to 220v inverter

[@Om_nom_nom_nom]

Video great. Sound is bad. The intro and outro hurts ears.

[@GSHElectrical]

Hi. So sorry my early videos have issues with sound however my latest 75 videos I have better microphones and a different intro. Sorry again But check out my new stuff thanks Gaz

[@floatybyboaty]

Surely the ‘Tails’ have lost one layer of their protection as they have been stripped back too far.

[@roholdt]

Amplify you self.