Spotting The Correct Earthing Arrangement Either TN-S or TN-C-S in a Single Phase Domestic Dwelling 

Always great content, I found this really useful

Excellent, concise explanation. Thank you!

I live in Thailand where TT without any earthing is used. Currently I connect a 16mm to strurial steel buried in concrete. Often the the supply cable is similar to SWA without the steel wire. If I connect an earth cable to the external of the neutral conductor imnediately prior to the KWH meter is this: 1. TN-C ? 2. In comoliance with BS7671 ?

Hi do you know if a PNB earthing arrangement should be treated as a PME when it comes to sizing of bonding conductors. Guidance note 8 shows it as TN-C-S which i can understand, but I'm not sure if the size of a combined CPC & bonding conductor of out buildings should follow figure 5.14 or 5.15 of guidance note 8. Any help much appreciated. Gary

Thanks

Good vid. Can an earth be exported back to CU to these 3 types of systems. It's for an SWA feeding a home office (no extraneous metal parts included, such as pipes etc etc)

Thank you it made easy to understand tncs tns

Some of those cut outs had two connector blocks in them, N and E separate. You’re can’t tell unless it’s opened.

So, in the last installation the earth is connected to the outer part of the incoming cable (TN-S) but also through the new earth wire to the neutral (TN-C-S). Is doing both safe? satisfactory? Why, when converting it, did they leave the old TN-S connection in place?

The last example you showed of an upgraded TN-S to TN-C-S certainly confused my CU Installer as he has ticked both TN-S and TN-C-S in the ECI document. I'm having a bit of a barny with NAPIT as well as he (in 2013) installed a dual RCD CU but failed to put my sockets through the RCD. All 56 socket outlets in the house are on a single circuit. On the Comments part of the ECI there is no mention of there being an exception to the regs. NAPIT say this is OK (did not need to comment) as he SHOULD HAVE put the sockets MCB on the protected side of the RCD. Its only this year through watching some of the UTube vids that I became aware of checking RCD's on a regular basis. CU's in a cupboad - no briefing at the time of install - no stickers on the outside of CU - No need for me to lift the CU flap and look inside - where the check quarterly stickers where. I tripped the RCD's and to my surprise all the equipment on the sockets stayed on. I am pursuing NAPIT to explore what my options are vis correcting the anomaly. At least they know what my installed has (not) done. Even left a blanking slot off the DIN rail so I could (foolishly) put my finger inside the CU. This amounts to a C1 as far as I can work out watching some of the Vids. Pigs ear of a cabling setup inside the CU with all the cables being joined with connectors. I could send you some picks if you want an example of a bad install for you learners.

Really helpful video, as I am currently studying for 18th Edition. Where do you get the maximum Ze from?

In the TNCS with the Neutral and the earth being connected together is that not automatically a Neutral to earth fault? I,m not a spark but Ive watched a good few vids . Also with the dual RCBs now required would having the earth and neutral joined in a TNCS not trip them ?This has been baffling me since i watched this one, I would love a reply.

In Above case of TNS .if Armour at Feeder pillar is connected to neutral than still it is TN S?

Do not assume an earth coming from the neutral side of the suppliers cutout is actually connected to the incoming neutral. Some older cutouts have an entry into the neutral block but required a solid link from the earth terminal to the neutral but is unseen behind the neutral plate. Retired jointer

Good video. Question. If a supply starts life as a TN-S but is converted to TN-C-S how do then ensure PME? They are not going to dig up the road and install numerous multiple earthing points?

Does the yellow stickers indicate it's coming from the yellow phase

The neutral in the first example looked horribly undersized. The final example was TN-CS plus TN-S. Surely both should be included in the EICR. My previous place, which was rewired to my spec., had all three systems (earth electrode plus TN-S and TN-CS). Ze was less than 0.1 ohm (in an urban environment). My home now is supplied from PMEd overhead lines: I have electrodes plus TN-CS. Ze without electrodes was 0.24 ohm; with two electrodes, reading was 0.17. I think that, if possible, an earth electrode in suitably conductive soil is a good thing for PME supplies, so that there is a path for earth fault current.

Also missed TT which is what a lot of properties are here

Terra is not French. Its Latin, meaning earth or land. Most name in physics come from Latin like delta etc.

You can’t just loop an earth out of the neutral into an ETB and suddenly it’s TN C S . It’s dependent on the system and jointing on the distributor.

What about IT system?

Apart from the music ! How about something a bit more catchy !

I hate adverts