1. B

    Earth readings

    TT system Ze is 17.5 ohms but when connected it is 0.60 ohms? Have one outgoing 95mm SWA and one 240mm SWA earthed either end and individual rods? Thanks
  2. Zdb

    Twin & Earth CCC

    I've got a RFC that I need to split into two 20A radials. I've looked in the BBB but it doesn't state the current carrying capacity of twin and earth in surface mounted trunking (reference method B). I've had a little look online and I think that it might be 23A (before taking other derating...
  3. C

    Earth Rods in TN-C-S and TN-S

    Why aren't earth rods required on a TN-C-S or TN-S supply? In the US earth rods are mandatory for both. Two earth rods if the first one is over 25 ohms. Here is how its typically done: View: #6 copper (13.3mm2) is run from the neutral bar of the first...
  4. HandsOffEngineer

    Should I earth bond test Class I appliances?

    Hello, I am a Trainee here on the Forum. I am seeking some further advice/input on a specific technical matter of importance to me. Briefly, I have completed C&G level 1 in electrical installation (distinction) and I am currently on the level 2 course, and things are going well on that score...
  5. B

    Clamp meter and earth leakage tester

    How do you use clamp meter? Do you just clamp the line? Or line and neutral? Also been working with a couple of guys that have earth leakage meters and one clamps the line and neutral and the other clamps the earth? Can someone tell me the correct ways? Thanks
  6. L

    200 Ohm ?

    Hi Everyone , I'm always confused that One ohm or less is a must for circuits supplied by a company earth . But when its an Earth Rod then up to 200 Ohm is acceptable ... Surely the rod is much inferior so should be less acceptable resistance .. I know we now have RCD's but Rods were in place...
  7. I

    Earth arrangement photo

    Hi All, Could you please clear for me the air with earth arrangement I've encountered today. Had a minor electrical work moving sockets and went to check the supply. I can see two earth conductors there. One goes to service head which suggests it's tncs and another connecting to outer sheath of...
  8. Pretty Mouth

    DNOs forbid PME earth being exported??? In the 1st paragraph of the above article, it states "some Distribution Network Operators (DNOs) may forbid their PME earth being exported from the supplied building.". I hear this repeated a lot, or "you must...
  9. bcm_spark

    110V DC Float Earth Ground Fault

    Good morning all, A 'ground fault' alarm came in over the weekend on the 110V charging system. We have two 110V fans currently running and I am suspecting that one is at fault but I can't turn it off yet to fault find. I say I suspect this as we have had to change them before because of low...
  10. C

    Glue Guns Failing earth continuity test

    Hi Guys Long time since I last posted but I have a problem I'm stuck on. My company uses a few industrial hand held glue guns. We have been experiencing repeated problems where the glue gun is failing on the earth continuity test. (Full test every 3 months) Typically 0.26 - 0.56 ohms. We...
  11. A

    Zs values when there is additional RCD protection

    Hi everyone, Consider we have an RCD+MCB protection for a circuit. if we follow the tables for Zs values of a 10A, MCB, type C, the maximum value shall be 1.75 Ohm, this happens when 100A current flows ( as per MCB breaking curve). When the RCD disconnects the circuit in much less current, why...
  12. D

    Twin and earth in pipe...

    I have popped this in the video section but thought it might make an interesting debate Handyman Chris has fitted some nice pvc pipe for his cable but rather than use conventional singles has pulled in twin and earth. Which seems odd when you have gone to the effort of fitting conduit pipe...
  13. A

    Earth Fault Loop Impedance Test for lighting circuits

    Hello guys, Do you do Earth fault loop impedance test for lighting circuits during periodic inspection ? do you measure it at the lighting point? what is the percentage of lights you test? Thanks alot in advance
  14. happyhippydad

    Would I still need a gland for the tails and earth on this TT system?

    The installation is TT. The meter box has been moved by the DNO. The tails will now be >3m so I will be fitting a switch fuse. I was planning on removing the DP switch in the switch fuse and replacing with a 100mA S type RCD. I would have put one in place of the main switch in the CU so this...
  15. S

    UK Wiring emergency lights

    Hi Guys, how would you wire three gang two way switch for emergency lights so you have 3 feeds coming to the switch aswell as 3, 3 core and earth going to the light aswell as 3, 3 core and earth being strappers to the others 3 gang two way switch new to electrics so help would be appreciated cheers
  16. E

    LED lightstrip earth

    Hi, I've got an Innr 4m light strip I'm running up my stairs, I bought an aluminium diffuser to run it in but I'm getting a very slight buzz/vibration on the aluminium when I run my fingertip along it like it's not earthed (no shocks or tingling). The light has 1 of those thin 2 core power...
  17. S

    Mr Nagy,s earth rod video.

    Just wondered if anyone has used this method with the earth wire in flexi conduit going to a plastic end box flat on the pavement outside the front door with the earth rod coming up thro centre of the box. Looks like a trip hazard to me. Regards,S
  18. S

    UK Should I get the main earth changed by the DNO?

    I have been asked to upgrade a fuse board, however, when I did an initial visual inspection, I noticed the main earth from the DNO is unsheathed (TN-S), it’s strands that are clearly ancient! I haven’t yet carried out any tests. Should I get the DNO to change the earth? Will they actually bother...
  19. P

    No earth or neutral

    Went to customers house yesterday (TT System) with a reported loss of power to the outbuilding. Checked the main consumer unit & the mcb was off, so flicked it back on, plugged in the megger & it showed 230v. But when I tried the lights or plugged in the Strimmer nothing happened, when tested I...
  20. J

    din rail mounted bell transformer - earth?

    hi i've bought a hager st303 din rail mounted door bell transformer and a 2 module wylex ESE2 enclosure for it to fit in. i was going to run this off a 3A FCU. i can't see any earth connection on the transformer from the photo - it haasn't arrived yet - and there's nothing to earth in the...
  21. S

    Earth wire loose under sink - advice

    Hopefully a very quick question. Whilst looking under my sink this morning I noticed the Earth wire between the hot and cold pipes is no longer connected. I can't recall if it ever has been but I'm assuming this has come loose and I should reconnect it? If I do connect it should I take any...
  22. B

    Broken CPC on Lighting Circuit

    First time posting so hope this is correct place? Been checking out a Customers Premises and all is good apart from 1 lighting circuit that feeds a bedroom and office. A CPC has been run but has been damaged/broken/cut somewhere en route to first light switch. (proved by using wander lead)...
  23. T

    Earth size for TT

    Got chatting to another electrician today who said about using 16mm earth for TT. Not that i have ever had to put steak in but am i right in saying its 10mm for a TT system?
  24. D

    3 core & earth to 2 core & earth

    Hi there. After a bit of advice please. Only reason I am not getting an electrician in is because my son is struggling with Asperger's at the moment, so just not able to let contractors in as he has meltdowns. I am in the process of simply replacing an old light from underneath a stairwell. I...
  25. A

    Commercial Fridge tripping

    Hi My name is Allen Brauteseth from Cape Town South Africa. I am a Qualified electrician and am sitting with a problem being I have a commercial fridge for cold drinks that trips out the earth leakage after running for 10 minutes please could someone help me as the supplier says there isn't...
  26. D

    High Earth current flowing

    I have measured high currents in the CPCs of four circuits as shown in the table below. This is the case both with the circuits energised and isolated. Removing the CPCs for these four circuits brings the current in the MET to DNO cut-out, back to genuine L+N measured leakage levels. However...
  27. W

    Earth Rod Connectors

    ok, so stupid question. its been a while since i have used any earth rods, and the first time since i was an apprentice that its for a tt system and not an earth ref for a generator. So iv got my rods in, and im going to connect it up but i have split the connector, two of them in-fact, i...
  28. Paignton pete

    Earth rod fluid

    Some where on this forum a while ago someone mentioned poring a special fluid (not urine) or resin down a hole by earth rod to improve surface area connection to the mass of earth in high resistance areas. What is this fluid/ resin called. I need to earth a new supply on. Very stoney, shale...
  29. Maxine

    Domestic Earth bonding for meters

    Hi, I am just after some advice. I am having new meters fitted and been told they need to be earth bonded? I've attached a photo as my friend thinks this has been done but I need to know before I book an electrician, so any help is appreciated, thank you
  30. T

    Domestic How to locate earth leakage wiring fault [Home wiring].

    Hello Everyone, I am from India. Things were good [seemed to be good] with temporary electric connection [single phase, 230v] to our new house. Now when we are organizing electrical wiring, dividing phases, installing ELCB, the problem started occuring. Now the electricity connection is of 3...
  31. happyhippydad

    Why the need for an earth spike test kit?

    I am about to put in a copper rod to TT a garage. I have a megger 1731 but do not have the Earth spike test kit. I will be able to test the Ze once the rod is in place and wondered what the difference is between testing the Ze and testing the Ra with a spike test kit? Is it sufficient to just...
  32. Sparksaflyin

    Dual board with no earth on final circuits

    Hi guys. Need to change the fuseboard at my parents house but none of their final circuits have a cpc run to them. Obviously have an earth on the main incoming so I can get a 16mm earthing conductor up to my new 18th edition metallic consumer unit but they don’t want a rewire so none of the...
  33. happyhippydad

    A question about how current travels through the real earth?

    When testing Ze on a TT the only connection between the line and the earth rod is the actual ground. When you do a Ze is it actually sending a small current through the actual ground from the earth rod at the house to the earth rod at the transformer? Also, related to the above, I have 2...
  34. C

    6mm earth tn-s question

    Hello guys After doing the adiabatic the 6mm will be fine as the main earth on a tn-s 60a 16mm tail fuse board. Is there any reason past the Calc this may not be ok as running a new earth may be tricky
  35. P

    Earth fault on water pump

    Alright folks, First time poster but im at my wits end! Got a mobile welfare unit which has a small 3kw hand wash in it. The water to the hand wash is fed from a small pump which comes on when the sensor for the hand wash is activated. There is a flying earth lead from the pump which is now...
  36. D

    Joining 16 or 25mm Earth Cable

    Hi any recomendations for products which I can use to join Two 16mm Earth cables. Going in a Fairly inaccesable place so trying to avoid Screw based products. Need to move an bonding cable for Copper pipe as boiler been relocated
  37. R

    Single core and earth lighting fault

    Could the better and wiser assist with an odd one...? I've just finished a big CU swap on a 1950's house that uses single core & earth lighting circuits. All but one of these are fine, but the faulty one is pretty funky; There are 3 accessories on this circuit in 3 separate rooms. The first...

    RCBO with Functional Earth Lead.

    I have read somewhere, (but I can't locate the source), that because the RCBO's electronic control operates at a very slightly higher potential than earth, there is a very small leakage to earth through the functional earth lead. Is this correct or is my memory playing tricks?
  39. A

    Main earth sizing

    Hi guys, Just wondering if anyone can clear up an issue. On tncs earthing systems, can you calculate the size of the main earth? I thought you could but main bonding conductors have to be sized to the neutral. Just had a conversation with another electrician and he said it has to be 16mm for...
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