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cpc

  1. J

    UK Voltage in the cpc

    So had a call out last night to a house late night the lights had all tripped. Had 2 lighting circuits in one breaker one with a dead short on it and the other is fine. While i was there I also discovered there was 110v in one leg only of a cpc serving a final ring circuit but its not tripping...
  2. Amnesh Singh

    UK Using Armoured as CPC, how to carry R1+R2

    Can anyone please help me, HOW to Calculate R1+R2 on 4 core three phase & neutral SWA, Armour Steel Sheet is Used as CPC. How to fill the Electrical Installation Form. This scenario is in AM2 Inspection and testing filling Certs Exam? Please reply with best answers. Any members those who took...
  3. P

    Install downlights - No CPC

    I have been asked to give a quote to install some downlights in a kitchen, but there is no cpc in the light circuit. I appreciate the response by some is the world would end if I did that, but the circuit is RCD protected and the last IR readings on the ciruit were good when the board was...
  4. westward10

    No cpc, really.

    Done a periodic on this a few weeks ago and back now doing remedial. This notice and the previous Report state there are no cpcs through the lighting. None of the roses have a cpc connected but there is at the conduit boxes they are mounted on in fact I have checked every light and there is a...
  5. L

    Very High end to end on cpc ring

    Hello, Just getting ready for my first scheme assessment and am completing a board change to be assessed on. Ground floor ring end to end readings. Its a 2.5mm ring T+E r1 0.71 rn 0.72 r2 8564 I have had all of the sockets off to check for a loose connection. The property has over the...
  6. D

    Max Zs /ADS / shared CPC & N

    Hey Everyone. Whats your thoughts on using a 3core & earth to run x 2 final circuits? I have x1 three core & earth feeding contactors for emergency lighting. L1- fed from a 6A mcb is feeding a switched pole on a NO contactor, L2- fed from a different 6A mcb also feeding a pole on a NO...
  7. FatAlan

    Another..Replacing lost CPC?

    Ok, so there have been a number of threads on old lighting circuits with no CPC. Also noted that it’s a no no to borrow a route to earth from another circuit. In this scenario I have two lights atop of brick gate pillars. I have good continuity and sound IR between the two pillars along with a...
  8. 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)...
  9. Sparky10

    Socket feeding DB

    Hi All, Visited a job today and was asked to supply and DB in a outbuilding via a Socket in the garden....:eek: i said i was not happy to do so and it wasn't possible. DB was suppose to feed 4 sockets 3 lights and a little plug in heater, Client claimed she was told by 3 previous electricians...
  10. happyhippydad

    Can I use the sheath of the SWA as the CPC in this example?

    Morning.. I have a garage fed by 4mm, 2 core SWA. It is a 25m run from the CU. Can I use the armour as the CPC? The Main house is TT. I have always used 3 core so have not come across this before. i am about to check my notes as I know I have information on this and will find the formula to...
  11. E

    Commercial Trunking CPC Continuity.

    Hi Guys, an old existing 25mm - TP & N SWA Supply cable is glanded (No Banjo) to a 3" Metal Trunking end cap, & the remainder of the circuit cables are contained in the same trunking forming the CPC back to the Distribution Board. With a method 2 continuity & an insulation test, can you be...
  12. D

    Volt reading across N and cpc

    I'm in a vineyard. There is a 300m buried SWA from the ccu direct to a 2 gang socket. I'm getting 247V across N and L at the ccu.... But at the socket I'm getting 100V across E and N and 147 across L and N. Continuity as a radial tested ok IR All over 500 M Please list possible issues here...
  13. B

    Testing pyro 2L2.5 cpc size

    When testing 2L2.5 & 2L4 pyro what size should be recorded for the cpc when using the outer sheath?
  14. Z

    Steel conduit used as CPC in flat, can’t find bonding, can’t find ring main CPC at C.U

    I’ve been asked to add a couple of extra points to the single ring main in a flat. Building fabric is concrete, all of the electrical installation is steel conduit buried in the concrete. I opened the consumer unit and could only see one CPC for a radial socket, as well as the main Earth. No...
  15. Simon-0116

    Moving db with no cpc in lighting

    Replaced a db on a tt system, but moved it about 1m. All circuits were required on rcbo. So I've extended cables. Now one lighting circuit has no earth. Obliviousy I know existing it's ok to have no earth if class 2 fittings, relevant sticker notices in place. BUT because I've worked on...
  16. Z

    Question regarding signing off 32a ring circuit with broken CPC ring continuity

    I installed a kitchen ring recently. Went back to test after the builders had finished and found that the CPC is broken somewhere inaccessible, everything else tests normal. I’ve got continuity on live conductors, and even with the broken CPC, each socket is connected to the CPC and tests with...
  17. S

    NO cpc lighting 18th edition

    Went to fit new light fittings in a loft conversion today. The existing ceramic half moon uplights were installed using 2 core flex buried in the plaster going I know not where! I've come across 2 core systems in old peabody trust estates that where complient as long as double insulated fittings...
  18. H

    How to test a circuits in steel conduit as the cpc

    Good evening I am currently a training to become an electrician. I do hold both initial verification and periodic testing qualifications however this is an issue I have never personally had to deal with and was never mentioned on any of my courses as often seems to be the case. Basically I am...
  19. J

    CPC Terminal in plastic surface mounted back boxes...

    Hoping someone can help me clarify something. For plastic surface mounted back boxes, why do some have a small metal terminal for connecting the CPC, whereas others don't? Is it just a differemce in quality, or would you generally use the ones with the terminal for sockets, and the ones without...
  20. Wilko

    Vintage Lamp CPC suggestions please

    Hi - been to fix a lamp today with a loose connection in the lovely terminal blocks. Then I noticed there's a brass lamp holder with no earth terminal and the earth is cut back in the wall. There's 4 of these fittings (8 lamps) in the room and they're probably all the same. Any suggestions for a...
  21. Adam_92

    1.5mm2 fp200 cpc size?

    probably a daft question to most of you, but in an 1.5mm fp200 is the cpc the same size or is it 1mm because my supervisor has told me it is the same as t&e but I’m pretty sure it is the same size :/ I’m trying to find it in the on-site guide.. Thanks Adam.
  22. D

    Domestic Bathroom downlight insulation coverable + exisiting CPC cut

    Pleased to find this forum, my 1st post! I will get an electrician in for this to make sure it's safe and tested but I want to understand what's right before getting a quote/posting a job. Previous owners had downlights installed in the bathroom but a later test certificate identified the CPCs...
  23. C

    Adiabatic Equation - why only for CPC?

    Why adiabatic equation is used only for sizing of CPC? Why not for phase conductors too?; As the fault current also flows through the phase conductors
  24. happysteve

    Low IR to earth (with no CPC)

    Here's an interesting one... :) Amongst other things, was asked to replace a 1G exterior socket with a 2G. Did some basic checks before I started, including IR (L+N to E) on the RCBO-protected socket RFC. ~0.26MΩ, uh oh. Sigh theatrically, ponders a day of unplugging everything then splitting...
  25. A

    Double insulated down lights cpc

    whats classes as the correct method of terminating an earth cable when you have double insulated fittings? You can see on the picture I can’t get a wage inside nor a normal connector block it’s just too tight. I have seen in the past the cpc being bent over and also snipped off which isn’t...
  26. happyhippydad

    Understanding minimum CPC requirements?

    My assessor said that the minimum CSA for a Main earthing conductor for a TT was 16mm. I questioned this as I thought it was 4mm. Regulation 542.3.1 states every earthing conductor shall comply with section 543. Section 543 refers mainly to the adiabatic (reg 543.1.3) or reg 543.1.4 (table...
  27. M

    Domestic Plastic Light fitting with metal trim & no CPC

    I have a couple of lights on a circuit that does not have a CPC. The light fittings are plastic but they have a metal trim that screws into the plastic body. I wonder if anyone can advise me if these are deemed as safe considering the main body of the light fitting is plastic and the metal trim...
  28. J

    Code 3 for usign Sheath of MICC as CPC

    This has probably come up before but I cant seem to find it. I have been presented with an EICR produced by another company where they have put a code 3 down for using the sheath of mineral insulated cables as the CPC. No further explanation on the observations and recomendations sheet. No...
  29. captaincaveman

    neutral live and cpc used as neutral

    Damn this heat. I just can't think straight! Been called to an installation where the ceiling was sparking near a light. All the lights were working ok. The spark was coming from a loose earth wire from the light fitting which was touching a metal ceiling frame. I checked the light switches and...
  30. J

    10mm t&e submain cpc

    I know there’s the adiabatic equation to work earth size but generally if you install a twin and earth cable for distribution, do you need to worry about the smaller cpc size My situation is 20 metre 10mm t and e run and not using it to provide earth bonding. Will the 4mm cpc be adequate. 50A...
  31. M

    No cpc on lighting and no neutral continuity on kitchen ring

    Hi All, I recently replaced an old rewirable fuse board for metal split load rcd board. However on testing prior to replacement I noted that one of the lighting circuits doesn’t have a cpc. I’ve put this in the EIC for the new board that no cpc for lights, advised client that needs rewiring and...
  32. dnjr

    Swa as cpc what size ?

    Dear all Testing a garage that is fed in 2 core swa using the swa as cpc Live and neutral are 2.5mm. I know the swa is fine as a cpc but I’m unsure what size to put on certificate for it Seen a table that says it’s equivalent to 17mm but in the back of my mind I remember you need to divide by...
  33. S

    CPC used as interconnect on smoke detectors

    We all know this is wrong and breaches regulations and manufacturers instructions. Good tread on this: https://talk.----------------------/topic/23387-cpc-as-interlink-on-smoke-alarm-circuitwhat-would-you-do/ However the question is does it warrant a C2 over C3? My recommendation is going to...
  34. S

    SWA cables - fly leading armour as cpc??

    Just after A bit of advice regarding a load of swa cables into dist board. What's people's preferred methods / good practice regarding banjos fly leads etc. Banjos inside?? If multiple cables are using armour as cpc is it considered bad practice to use 1 fly lead between the two Banjos??? Is it...
  35. Michaelwgroves

    Using adiabatic equation for CPC on SWA

    I want to use the armour as my CPC but need to check it complies. The cable will be run from a SP Distribution panel to CU. As per Selection and Erection Guidance Note 1 table D10a I can see a 10mm XLPE SWA requires a 31.1mm csa to comply, but only has 26mm on 2-core. 20171231_114229828_iOS.jpg...
  36. J

    tapping into conduit wiring with no singles cpc

    Afternoon guys Got a job my builder wants me to do in nice block of flats up town solid concrete ceilings/walls/floors unfortunately! lighting is just staying as is- but them want extra sockets added and a new 5amp socket circuit for lights the existing sockets are wired in single in tube in...
  37. O

    No CPC on lighting circuit ............

    OK, lets have a decent discussion about this as I'm sure there will be a number of opinions! Have done an EICR on a 40 + year old flat. The lighting circuit is wired in singles and utilises the steel conduit as the CPC. Out of the 6 lights and using my R2 wander lead, only 2 have an acceptable...
  38. T

    No cpc to lighting circuit, no rcd protection 50 year old wiring

    Hi just thought I'd throw this out here for a bit of light entertainment after the @Marvo thread (phew!) So brother in law asked me to look at EICR which returned unsatisfactory. I have not looked at the installation to ascertain as to Class 1 or 2 fittings in the premises are installed. The...
  39. S

    CPC size of SWA Armouring

    Evening, Just joined upto this forum after a search online for some info, hopefully someone can help me? I have taken over a job from another contractor who has run in a 50mm 4 core swa from a substation to a TP&N DB roughly 100m away. My concern is that it appears they have not run a separate...
  40. D

    Metal Light Switch + Plastic Back Box with no earth terminal

    I've tried to find a solution on here to this exact scenario but had no such luck. Could somebody please advise on where I should place the earth wire on a plastic back box with no earth terminal when adding a new metal face plate? The face plate has an earth terminal on it and was probably...
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