1. D

    Judging imperial submain T&E cable

    Doing an EICR on a top floor flat recently and run into an issue I often do - which is judging imperial sizes when they are larger than the standard 1/1.5/2.5mm equivalents. In this case, the flat is fed by a Twin and Earth cable that is somewhere around the 10-16mm range equivalent, with an...
  2. M

    DNO UK power networks changed incoming overhead and now have PME TN-C-S but ccu connection to TT

    Hi all. I'm currently training as an electrician so would like your views on this for clarity and if I need to get someone in? I have just moved in to a new (very old) house and on inspection of the CCU I noticed the incoming service cable from the overhead was chard at the top of the dno head...
  3. I

    Use of Singles for Main Earth Conductor and Incoming Neutral?

    Hi folks, Limited experience here and never come across this before. Whilst I can appreciate the conductors may be the appropriate CSA combined, (I haven't measured them) terminating the Main Earth Conductor in the MET like this with what looks like 4 x 4mm2 doesn't allow for the conductors to...
  4. OnlQQker

    UK Why Are Incoming Live/Neutral 16mm and Tails From Consumer Unit 25mm

    I just can't seem to understand this and can't find a clear reason behind it either. I asked a chap on the DNO once and he didn't know either. Anyone?
  5. H

    PME? Questionable incoming supply

    So i went to start a job on saturday and i came across this. It is a single core pyro with an earth tail pot, ignore the henley block in the trunking as that is obviously just to extend the pyro but what they have done is come out of the ryefield into the meter with the phase conductor then with...
  6. D

    UK 3 Phase PME to domestic building?

    Good evening all.. I have recently installed a new 100amp 3 phase supply for a domestic premises with outhouses. The incoming 100 amp supply is PME and approx 30 metres from the main dwelling, a new metering cupboard was built for the new head and meter. I installed a small sub board and two...
  7. Marcus Vaughan

    BS951 Bonding Clamp on the Incoming Supply

    Hi all, Just been to look at a job for a consumer unit changeout, checked the supply and, Not sure you can see it too well but TNS system with older earthing conductor in green kind of sweated onto intake (connection does not feel too good), but disconnected at the other end (goes into that...
  8. J

    Bonding - CU or Main Incoming Fuse

    I'm aware that a 10mm earth cable needs to run to the incoming water and gas supply but I was wondering if someone could tell me whether this should be from the consumer unit, the main incoming fuse, or both? TIA
  9. Daniel Oake

    What are your opinions on bonding water pipes if main incoming is plastic?

    You turn up to a property that had recently had an EICR, reporting that the water had no bonding. The main water stop cock and on-wards was plastic push fits with maybe 400mm lengths here and there (downstairs), but upstairs is still all copper piping behind bath panel and sink pedestals to 2...
  10. C

    Main bond to rubber incoming water pipe.

    Had DB changed a couple of years back in my house that I was renting that I now live in. I was out of the country at the time. No certs were handed over and I am unable to get in contact with the guy that my parents got to do the work. I am in the process of selling the house. The 6mm bond to...
  11. J

    Can incoming mains run above ground under suspended floor?

    Hi all. I'm looking for some expert advice on the above. I am having an extension built and the footings are a raft slab which can be built/poured under the existing incoming mains cable (it's in a black pipe approx 50mm dia). There will be a suspended floor approximately 100mm above the...
  12. S

    Old Incoming service cable/head. Does it need replacing?

    Hi all, My brother has just bought a new house, which is to be fully refurbished. The wiring is appaling and barely meets a single reg; current or historical. (no part of either RFC seems to actually be a ring, lighting on 15A 3036 fuse in 1mm, spurs under the carpet etc etc) All of this will...
  13. J

    overhead incoming supply TT TNCS?

    Looked at a rewire for a 5bed house reno this morning bit of a odd setup! so the house is supplied overhead- see pic 1- 2cores through the roof in loft into a 60a fuse then what looks like a 16mm T+E- but cpc (if one) is not used this travels some meters (at a guess 10m) down to the ground...
  14. R

    >2000 ohms on loop test?

    Hi guys, Was wondering if anyone could shed any light on why I would be getting >2000 ohms on my loop tests, on every circuit? I got .26 on the incoming reading, went to do the test on the cooker circuit and >2000, thought I'd try back at the consumer on the incoming and >2000 again, I'm using...
  15. D

    SMA 4000TL 'Insulation resistance' error

    I've recently found the green light flashing and the red light on on our SMA 4000TL with the message 'Insulation resistance, check generator' on the display. Checking the ERROROB2.CSV files I can see that this isn't the first time it has errored in this way, it has happened on odd occasions for...
  16. Adie moore

    rcd bust?

    strange goings-on or it might be me, this is what happens; • 3 lead loop test on final circuit = rcd trip • 3 lead loop test at board, outgoing side of rcd, all circuits off = rcd trip • 3 lead loop test at incoming side = rcd trip • rcd test at outgoing side= X.5 no trip X1 45ms X5 29ms...
  17. A

    Commercial Using pipe work to bond to incoming water

    I have recently come across a situation whereby instead of running a main equipotential bonding conductor from the MET to the incoming water someone had instead ran a short bond from the MET to some copper pipe in the mains cupboard and clamped it and then placed a bond on the pipe near the...
  18. 3

    Domestic earth voltage

    I am checking an install and noticed the voltage between line and earth is 190 volts. I checked incoming supply voltage with the main consumer unit isolated and am getting 220v l-n and l-e when I switch cu on voltage l-n is 220 volts l-e drops to 190 volts I have disconnected all circuits and...
  19. H

    First time I've come across this fault

    Had a call, the lady had no power in her property. Turn main switch off remove cover and test at incoming side of switch 230V. Turn main switch on and at the other side of the main switch 50V. Faulty main switch I thought. Turn off all RCD's and MCB's and have 230V where I found 50V...
  20. M

    main switch

    Hi all Is there a regulation in the bgb that states you cannot come off the main switch to feed another db, not that I want to do this I've just come across it being done today
  21. D Skelton

    Any telephone wiring experts here?

    I have to replace a BT master socket and I'm replacing it with a modular master socket as I'm fitting dado trunking right across where the original master socket is sighted. I know technically I shouldn't be doing this because BT might get a bit aggy but needs must. I'm fully aware of the fact...
  22. C

    3 phase Incoming Supplies

    Hi, With reference to the main incoming supplies on mainly 3 phase and the requirement to fill in the Type of supply & the fuse rating for the supply, sometimes together with the Main switch details - I often have dificulty with these as the majority of times the supply cable and incoming fuses...
  23. R

    transformer design using relay and contactors

    ok,lets say the transformer getting input voltages 380-400-440-480-660-690 V and out put is 230-440 v,the tappings provided for the incoming voltages but the incoming will be the same connection either it can be of any voltages,how can it be done by the use of relay and contactors for different...
  24. 5

    A couple of AM2 questions.

    Hi all, I'm new to this forum and its due to the fact that I have my AM2 exam this coming Monday. I just have a few questions. - Do I need to earth bond the cable tray? - I know that the External Loop Impedance Test is on the incoming side of the installation, and that when testing i need to...
  25. P

    polarity testing

    hi guys, could do with some help. I undetand how to do my polairy testing on a normaly circuit. e.g lighting circuit. but how do you do polarity testing of the incoming supply? thanks
  26. R

    PIR on Caravan's help please . . .

    Hi guys, am new to the forum although I have been reading threads on it for a while. I am looking for a little help on the job I am currently doing. I am currently carrying out PIR's for a number of caravans on a large park, but am getting pretty puzzled when coming to fill in the 'SUPPLY...
  27. S

    Connect PV into main breaker in CU

    Is it possible to take the PV circuit from the inverter via it's own RCBO in the CU into the incoming breaker thus connecting to the main live tail before the house circuits. Will the PV then only flow past the breaker if it is required to feed house load and any balance will be exported...
  28. F

    mains supply to flats

    had a customer enquirey to change card meters in some flats each flat is fed with 10mm twin and earth and each flat has its own earth stake on fuse fusebox side of flat,each flat has a 30ma rcd inbetween incoming supply cable and fusebox. however there is no earth stake for the incoming supplies...
  29. A

    Live Testing - PEFC / PSCC

    After a little bit of advice please We are doing our Dead and Live Testing at college tonight. I am ok on most of it but due to not having much time to practice our live testing I need a bt of advice. Live Test: CCU breaker off Prove VID - Test for dead with VID - Re-prove Ze - remove main...
  30. Baker1988

    Urgent help with domestic supply in my house

    Hello i was wondering if any one could help me i am doing my level 3 at college and have a bit of knowlege but not loads the problem is i woke up this morning and my electric wasnt working i checked the meter and every thing seems fine then i checked the db and it had power too it if i turn all...
  31. J

    Outside building supply

    Hello All I am currently constructing a cattery 70 metres from our house I will be running (if all on ) 5kw of heat lamps I will also have a 32a ring main and of course lighting My plan is to run 16mm swa from a henley block split from our house cu The house is a TT earth (with incoming...
  32. R

    Domestic MR DNO Palava

    Hi guys, I am carrying out a full install to one(top) of two flats from a converted house. Originally the house had only one incoming service head (single phase)to the property, but the new landlord decided to contact the DNO about upgrading the incoming service possibly from a 3 phase to one...
  33. P

    Forms during Installation

    I am just in the process of getting ready for assesment. I was wondering if anyone has any advise on forms they are using or pre-made for checks during installation and commissioning. This includes forms for proving the incoming inspection was completed and the process inspection during...
  34. Pip

    How can you Earth Bond plastic incoming mains water pipe?

    Hi People, Looked at a job today which requires adjustments to the CU and noticed there is 16mm from CU to MET which is cool, 10mm from MET to Gas main incoming, and bonding between all pipes coming in and out of the boiler linked off the GAS main bonding. When I pointed out that there...
  35. L

    Mains Bonding???

    I recently was testing a flat and found that the 6mm Mains earth to water was not accessable but the valve for incoming is so may be able to test from board to incoming for a result but do Elecsa officials want to actually c the bonding position as its one of the assessments for elecsa??I...
  36. T

    Fluke 1653b

    Hi all just got a fluke 1653b and was just testing my house for some practice tried to test Ze and im just getting a warbling sound out of the thing and no result, i think or should i say i hope its only the batteries need replacing also whilst im on the subject how long do the batteries last on...
  37. G

    Ze Test come up with 'fuse'

    Hi All am new to this site and am hoping some one can help. I am in the process of changing a fuse board, on testing ze (disconnected earth from board connected neutral clamp to the N bar and phase tester to the incoming live)..........push the button and bleep bleep 'FUSE' comes up on the...
  38. L

    Anyone have a good knowledge of BT systems etc?

    Need to get some answers about multiple line dialing systems. cheers
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