1. B

    Adiabatic Equation

    Hi All, I think I have confused myself somehow and feel I am spiraling into further confusion. When I am doing the equation, it is saying the longer the cable is, the smaller the CPC has to be. My calculations are below. 20A radial BS61009-1 Curve C Install method type B using 2.5 singles...
  2. 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
  3. S

    Help with Adiabatic equation

    Hi, Could anyone check my calculation please. Protective device 60A 1361 E.S = TN-C-S Cable 16mm T & E CPC 6.0mm Zdb = 0.43ohms Multiplier temp 1.20 0.43 x 1.20 = 0.52ohms 230/0.52 = 442A SR 442 squared x 2secs/115 = 5.43mm Cheers
  4. Zdb

    Adiabatic equation infinite loop

    So I'm looking into the thermal constraints of every cable in my 2396 project. I've used the adiabatic equation in a spread sheet and 99% of them are fine with the CPC I have selected. However, there are a few really short circuits with very low earth fault loop impedance. Because of this the...
  5. J

    SWA r1r2 35mm ... .....

    Could anyone give r1r2 values per metre for 3core 35mm SWA also incorporating the armour as a protective conductor? The figures I've obtained are 0.00282 but I'm unsure if this incorpartes the armour. It's to supply a bungalow but the meter and cut out is 160 metres from the house itself...
  6. 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...
  7. 1


    Hi all need some advice please got a 16mm twin earth submain in block of flats to flat 1 coming off a 60 amp dp isolator so main earth is 6mm water and gas is bonded to flats met via 6mm what code would I use for eicr? Or should I do the adiabatic calculation first to see if it compiles
  8. D

    industrial welder. any advice

    Hey guys I want help on this forum about cpc and I heard I won't get any am I right?
  9. R

    Flat supply wiring and fuse protection.

    Any ideas on this one? I am doing a survey/eicr on an intake serving 9 flats belonging to a local housing authority. The cables are early 70's 16mm/6mm T&E run through the building structure. I have assumed the maximum draw is around 30A per flat and checking the Ze values and distance it...
  10. Guitarist

    Supplies to outbuilding CU's

    Do you guys think that the majority of electricians actually bother using the adiabatic equation to decide whether the cpc of a T&E cable is adequate when supplying a CU in a garage/shed, or do most people just size the cable based on CCC and voltdrop? I come across a lot of T&E strung between...
  11. H

    help on pirs

    Hi all, Completed my first pir yesterday (: now this client has got a three phase supply, TNS which feeds a ground floor shop and a flat above, the flat has a on peak and off peak supply. With the tails for the flat going into two kmf switches with a sub main cable of only csa of 10mm T+E for...
  12. B

    CPC for shower!

    Hi guys, i just changed a 8.5kw electrical shower for a friend, the live is 6mm2 and i believe it is fine, the only thing is the cpc, looks like 1.0mm, at most 1.5mm, i checked codes, but still not sure about it, is this cpc ok? cheers
  13. carl9254

    Building Control

    Hello, got my Elecsa assessment on 4th january, going to change the cu in my house and use that as assessment job, its simple as only 3 circuits, sockets, lights and shower. But shall i tell building control?? Elecsa said upto me, they dont request it but they will let building control know...
  14. Z

    Circuit design

    Hi all! When you are designing new circuits, do you design for both overload and fault protection for every case? Or for fixed loads design without overload protection and make adiabatic check as well?
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