cpc


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  1. 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...
  2. 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...
  3. 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...
  4. 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?
  5. 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...
  6. 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...
  7. 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...
  8. 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...
  9. 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...
  10. 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...
  11. 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...
  12. 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.
  13. 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...
  14. 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
  15. 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...
  16. 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...
  17. 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...
  18. 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...
  19. 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...
  20. 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...
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