Electrical2Go - Online Electrical Supplier
This official sponsor may provide discounts for members


  1. GBDamo

    2.5mm or 4mm SWA armour bonding

    Armour not CPC. By the letter of the regs 2.5mm is acceptable as the DB offers both mehanical and corrosion protection. Just seems a bit puny on a 10mm SWA, what about a much larger cable? Can some of the boffins explain why 2.5mm is deemed acceptable. Cheers
  2. Fitzy

    Domestic SWA outer armour not earthed at either end.

    A friend at work asked me to take a look at the electrics in his shed, RCD would occasionally trip out, turned out to be a very loose neutral going in to the RCD. One thing I did notice though was that the 10MM2 SWA entered through the back entry point of both the shed & house CU and neither...
  3. 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...
  4. 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...
  5. B

    Swa armour feeding TT system

    I have installed a TT system at my garage, and it is fed via 10mm 2 core armoured cable, does the armour of the cable have to be earthed via the supply tncs side or can it be glanded and earthed the garage side (TT). Anyone know the regs ? Thanks
  6. Wilko

    SWA Armour Use Descriptions

    Hi - various discussions we've had are summarised in this Voltimum information paper. Interesting for me was they effectively say main protective bonding in PME installations should be external to the cable, due to heating risk. I'm still digesting this myself ... The earthing functions that can...
  7. C

    Testing ze with armour as earth

    Hello all, Quick bit of background, factory maintenance spark for 20+ years, covered some installation work over the years but not done a great deal of testing. New lines and cells are being installed over the next few months and all installation is being done in house. Decided it is time to...
  8. Sparky_marky2

    SWA armour supply to outbuilding, what CSA cable? and Reference Method?

    Hi guys, I am running a supply to an outbuilding that requires a 22m run from the Main CU (in the garage) to the CU in the outbuilding, at the Main CU it will be a 40A MCB supplying an 63ma RCD protected sub board which will then supply: 6A type B MCB for 12 downlights and an extractor fan 32A...
  9. H

    EICR Coding - Armour not glanded

    Doing EICR on a HMO, DB feeds a Consumer Unit in each room. The feeds to each consumer unit seem to be SWA however the armour is not visible/accessible at either the consumer unit or the DB - it seems to have been cut out behind the DB which is inaccessible. The cable is buried in the walls and...
  10. M

    Resistance per meter of armour

    I know it's late and the lap dances are still open , so i will wait till tomorrow for any replies . Does anyone have resistance per meter tables for steel armour 90degree thermosetting ,can't find it anywhere . Ta
  11. M

    Electrical installation design guide

    Have been sizeing up the size of armour on diffent SWA cables to make sure they are suitable to be protective conductors. Come across table 8.8 page 100 .on this table it says maximum bs88 fuse size (for example) 120mm 4core is 500a, when it also says current carrying capacity is 335 method c...
  12. D

    Supply to static permanent residence caravan

    Hi, looking for some advice for supply to static permanent caravan at bottom of garden. My House supply is TT. From what I can gather from previous thread s, is this acceptable. House end, SWA terminated into plastic ad.box and l+n tails into non RCD side of cu, from suitably rated MCB. Armour...
  13. haptism

    SWA test results

    Hi hope someone can advise; ive not done alot of testing or filling out eic's and am a bit stumped on this. I have run the usual dead tests on a 3 core swa cable used on a final circuit all tests are good. However the amour (which needs to carry the full fault current), does it not need to be...
  14. M

    25mm armoured to 16mm earth conductor

    i have to send a 75meter run of a 3 core 25mm armoured from the meter to the fuse board. now due to the lenth i have to have a switched fuse and possibly a isolator on the otherside. due to the earth being 25mm i know alot of isolators only take 16mm. is the use of a helely block perfered to...
  15. M

    Domestic PME to remote domestic dwelling

    Hi guys, thoughts on this would be appreciated. I have a 3 phase 100 amp PME supply, feeding 3 domestic dwelling about 80 mts away. Done cable calc and have chosen 50mm 4 core swa using armour to protect cable. In the 1st dwelling I have 3 phase metal DB feeding 3 sub mains, 1 to 1st & 2nd...
  16. D

    Domestic Armour cable ran to garage on 16a breaker

    Hi Everyone, I have armour cable running from my house to my garage in a new build, it is connected to 2.5 that connects to my consumer unit, can i put a socket before armour cable for my wifes new battery hoover without any adverse effects? its protected by a 16a breaker then runs to garage...
  17. G

    Domestic Rcd outdoor skt.

    Hi guys quick question. Neighbour wants outdoor skt at garden shed. Her house has no rcd protection. Old rewirable fuse board. Cable to be buried underground. Going to spur off closest skt, then out to shed in armour cable. Without upgrading the fuse board is there any way I can rcd protect the...
  18. S

    SWA Testing cpc continuity!

    Hello just wondering if anyone could help me! I have to test a circuit tomorrow wired in SWA that is using its armoring as its earth, To carry out the R1+R2 test how would i eliminate any parallel paths? Surely the only real way to do this would be to remove the cable from the side of the metal...
  19. keniff

    Domestic 3 phase

    What's the norm on a 3 phase Submain in regards to swa and earthing, I'm looking at 25mm swa but not keen on using the armour as earth, (it works out ok size wise) I normally use an extra core for earth on single phase but 5 core swa seems a bit thin on the ground anyone have fors and againsts...
  20. P

    Circuit design - SWA R1+R2

    Hi all This has got me thinking. I am designing a circuit using 3 core 2.5mm SWA and using table 11 in the OSG on page 182. With an R1 of 2.5mm and the same for R2 I know what the milli ohms per metre is. That's all well and good but I also know from experience that when uisng the armour as an...
  21. G

    Earth Cable To Sub Distribution Board.

    Hi All, I recently installed a new dist. board with 95mm sq 4 core swa cable. I used 35mm sq earthing cable even though I should have used roughly half the size of the live conductor. I used this because I had it, and was hoping it will be ok. I now fear that the cross section of the cpc...
  22. the pict

    out buildings

    This has been rattling around in my head for some time, I have read the guide in the sticky section about exporting etc,so a building outside the equipotential zone should not have the earth exported, right ?, and a spike (s) should be used, but, what about the armour this should be terminated...
  23. Amp David

    Indoor distribution circuits

    Have been working in a small packaging company today along with another local spark, installing a couple of single phase distribution circuits. 99.99% of my work is domestic, so was really along with him to help and learn a bit more at the same time. The questions I have is why do some guys...
  24. O

    swa in conduit/pipe underground

    As title says really? Heard people say use in some form of piping to make life easier in future should you need to replace/pull in new cable Others say bury direct? What's your views Cheers
  25. R

    Outbuilding supply from TT system

    I am wiring an outbuilding, to be used as an office at the moment. I am nearly at the stage of running the supply out to it from the main house. The main house has a TT supply. Would the correct way to do it be to use a 63a 100ma time delayed rcd to protect the swa supply, and 30ma protection...
  26. S

    Armour sheath carrying a voltage

    Hi guys, Had a situation the other day where the armour sheath on sub mains was carrying a voltage of about 55V.The sheath was not being used as an earth and was only there to give protection to the cable. Can anyone tell me why this occured? Many thaks
  27. S

    Testing SWA

    Does anybody know what table in the regs gives the size of armouring in mm when using the SWA as a CPC ? so i can write this in the circuit details on the installation cert.
Top Bottom