• Welcome to the new forum. We're now hosted on ElectriciansForums.net rather than ElectriciansForums.co.uk - Chat about the forum upgrade by CLICKING HERE

Welcome to our Electrical Forum - We started out providing electrical advice just for the UK - But now we have specific advice for the USA too! - Register for free and share American Electrical Advice.


  1. S

    Broken PEN conductor

    Attended a seminar today based on EV charging points. The broken PEN conductor was mentioned and converting to TT. 2 things. 1. How often does a PEN conductor go down?? My understanding was that they use PME to reduce this risk further. 2. I asked the question as to should we be installing...
  2. Strima

    Main Earthing Conductor Termination with SPDs

    Here's a question that I was asked earlier. If you have SPDs installed in a DB is it permissible to terminate the main earthing conductor into the SPD first then the DB earth bar? Or must it be terminated in the DB earth bar first then the SPD?
  3. C

    Conductor Operating Temperature H07RN-F

    Hi All, I'm trying to calculate CCC & VD for H07RN-F Single core cable. Used for event powerlock runs. TPN AC - Ref Method C - Flat & Touching Table 4E1A/B covers Single Core 90*C thermosetting insulated cables, which I have used correction factors to convert these values to flexible cable but...
  4. S

    Main Protective Bonding Conductor question

    Hi guys Would appreciate your comments on the following.. I am currently involved in the refurbishment of a building with 2 service heads (both in use) but only one gas intake and one water intake. What are the main bonding requirements in this situation? I am assuming both MET's require a...
  5. V

    SWA cable , TT, do i need an earth conductor in the cable?

    At the origin the installation is TT. Plan is to install a submain to a new db. Not carried out all the calcs yet, but my question is does the swa require an earth conductor in the cable. Basically planning on running a phase and neutral or perhaps even 2 x phases and neutral.(the cable will be...
  6. B

    Commercial Defining what equipment has protective conductor current

    Hi all, I have an engineer who has failed a wall mounted data cabinet because the PDU is hard wired into a switched fused spur, the spur is spurred off a ring main in 2.5/1.5 twin and earth. He has failed it under regulation: 543.7.203 The wiring of every final circuit and distribution...
  7. T

    Main earthing Conductor also bonds water

    Domestic TNCS, main earthing conductor runs to water pipe, bonds via clamp with label, cable is continuous, then runs on to MET in DB. Seems wrong, but cant find specific reg to say so....any thoughts? Thanks, Timotei
  8. P

    High Zs on SWA Armour / New Earthing Conductor

    Hi all I am after some help/Advice if possible please A SWA sub main Distribution circuit has been given a Code 2 Rating on a recent EICR due to a high Zs of 2.8 ohms. The cable is 180 metres long and runs underground in ducting. The Install is from a few years ago when a new Substation was put...
  9. D

    confirmation of earthing conductor size

    Hi Guys just a quick question but what the hell do I put in confirmation of earthing conductor size when the earth is the swa
  10. leep82

    C.P.C in T&E as a live conductor

    I know the thread title sounds bad but hear me out. I have wired an intermediate switch set up with feed at one switch, switch wire at another and twin and earth as my strappers between to an intermediate switch. My customer wishes to use lightwave switches for the three posistions mentioned...
  11. C

    protective bonding conductor size

    Hi guys, I've questioned something at my workplace and after receiving my answer I'm not overly convinced and would like some other experienced gods to chime in :) On a new install in an existing property today I went to bond the Water and noticed it was already done, clearly many moons ago...
  12. G

    High integrity earthing.

    i understand the need, as I see it any circuit with a likelihood of more than 10 mA earth leakage should be subject to high integrity earthing. This requirement can be achieved by many methods and I can see the sense in some. Using RFCs instead of radials gives two paths so in the event of a...
  13. R

    Coordination between conductor and oveload devices

    A good memory trick for exam conditions for coordination Ib In Iz (Alphabet) the earlier letters are always lower in value than the earlier ones, saves remembering Ib < In In < Iz Ib < Iz
  14. kingeri

    Extraneous conductive part as bonding conductor

    Been nosying about at my brother's new house this week and fixing a few bits and bobs. The electrical installation mainly dates back to the early 80's at a guess and apart from a few broken accessories and a lack of RCD protection (now fixed) it has all checked out okay. PME earthing. Today...
  15. Andy78

    EICR - Undersized earthing conductor

    Doing inspections today and found a couple of properties with under sized earthing and bonding conductors. Earthing system is TNC-S and features 6mm earthing conductor and 6mm bonding conductors. I normally code 6mm bonding conductors as C3 and am happy to do so here too, but should I be coding...
  16. J

    Supply conductor size for 8 bedroom Victorian house

    Hi folks, I've recently visited a large 8 bedroom Victorian house. It has a three phase supply. One of the phases feeds the main house, its wired through a 100 amp main switch/ isolator. The Suppliers Side is 25mm tails but the customers side to the main house consumer unit appears to be 16mm...
  17. J

    What code? bonding conductor

    A connector block has been used to extend a 10mm water bond, what code would you recommend? Thanks
  18. Michaelwgroves

    Can you join Main Protective bonding conductor

    I have a 6mm main protective bonding conductor from a 1981 install; adiabatic equation says this is sufficient and no signs of thermal damage. (Discussed in separate thread). Gas was not bonded, it's a big job to run new cable so I've used redundant water bonding as now all plastic to bond gas...
  19. Marcus Vaughan

    6.0mm earthing conductor to MET on TNS

    Hello. I am carrying out an inspection on a domestic TN-S system. First observation is that I can see 16.0mm earthing conductor fro CU to MET - but then is steps down to 6.0mm connecting to the supply cable. This should be 16.0mm - shouldn't it? I am going by table 54.7 in the big yellow book...
Electrical Insurance
ElectriciansForums.net (formerly known as ElectriciansForums.co.uk) was setup in April 2006 to provide free electrical advice to both professional and DIY electricians. Whether seeking advice for auto electrics, trying to find electrical installation condition reports (EICR) form downloads, or whether you're here just to talk to other electricians; we've been a first-choice website for tens of thousands of sparkies for well over a decade.