adiabatic

adiabatic

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  1. S

    Adiabatics not complying on short-length circuits/faults close to CU

    Firstly, please go easy as I'm still a trainee! Working on my L3 2365 I'm having trouble understanding the rationale behind adiabatics calculations for CPCs, because it seems to me that if you had a fault close to the CU on a longer circuit, or a fault on a short (in length) circuit, you'd have...
  2. frontier219

    TN-C-S/Adiabatic help!

    Afternoon all, Got a bit of a strange one (by my usual standards anyway). Job is a large barn conversion, done years ago, there's loads of work to do in the outbuildings as they are renovating those, but they aren't touching the house just yet. Main intake is a brick built building about 2-300m...
  3. S

    Adiabatic Equation help

    Hi was wondering if im doing this right. The question in: Determine for a chosen circuit "the minimum possible csa of cpc which will satisfy the requirements disconnection as ADS under earth fault conditions and the adiabatic equation as reg 543.1.3." Circuit: Single core pvc 70* 2.5mm2 +...
  4. G

    Help with cable calculation please

    Hi Help please with the adiabatic I am doing a small design for my course and I can't figure it out. Any advice will be appreciated. Ring Final Ib: 30A In: 32A It: 20A Iz: 21A 2.5T&E method 100 V: 229V Ze- 0.22 Ohm L: 26m So r1+r2 = 19.51*26*1.2/1000=0.6 Ohm. R1+R2 = 0.6/4 = 0.15ohm...
  5. I

    Cable Calculation Help - Adiabatic Equation

    Need help check that my cable calculations are correct as still new to doing them. 6A Lighting Circuit 60898 MCB Type B wiring in 1MM²/1MM² T+E supplying a single 10W outdoor light Length = 3.3M Zs@db = 0.22 R1 + R2 mΩ/M = 36.20 mΩ/M - Table lt P218 OSG Correction Factor - 1.2 - Table L3...
  6. B

    Could anyone please help me with this adiabatic equation?

    Hi, and thank you to anyone who's taking the time to read my question. i'm struggling with the outcome of an adiabatic equation i'm doing and would be incredibly grateful of any guidance or help anyone could offer. its for a design project and i'd like to know if i'm doing something wrong...
  7. Rockingit

    Calculation of VD within/as well the adiabatic?

    Here’s something I’ve never thought about until now…. So, we use the adiabatic to return an S based on the usual parameters and for arguments sake we end up with a 35mm conductor. But what if it’s also 300m+ length end to end before the earthing conductor gets to the MET? Do we then also...
  8. C

    Safety of Using Adiabatic Method?

    I'm thinking, and while I could be wrong, is the adiabatic method a possible latent safety hazard? As well as undersized CPCs on circuits 32 amps and under? Normally DNO sources are strong with relatively high PFC, and we have a known Ze value. However, should someone bring a portable...
  9. spud1

    Adiabatic equation help

    Hi guys, I had a brain fog on the adiabatic. Trying to ascertain suitability of a 6mm bonding conductor in a domestic installation. Doesn't help that I forgot my regs book too! I have a pefc of 1.17KA. Can anyone help please? Thanks.
  10. J

    Adiabatic

    Does anyone know if the adiabatic equation applies to aluminium conductors when calculating the csa of earthing conductors, or guide me to where I might be able to find an answer. Cheers
  11. C

    Need Help Learning to Compute Adiabatic Method

    How would I go about calculating it for any given circuit? Lets say I had a 60 amp feeder, 13.30mm2 phase and 5.261mm2 earth. How long could I run the circuit before the 90*C insulation on the earth wire overheats for a fault? At what point would I need to up size my earth wire?
  12. 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...
  13. 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
  14. 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
  15. 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...
  16. 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...
  17. 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...
  18. M

    Adiabatic equation on distribution circuits

    Now I know this has probably been covered a few times but I'm struggling to come to terms with my own calculations. I would appreciate it if someone could tell me if my calculations are correct. So basically I've done a periodic and some of the CPC sizes for sub mains are less than half the...
  19. A

    adiabatic equation help!

    Hi guys, really need help to solve this question i have on my assignment for my apprenticeship not asking for the answers but for guidance page numbers etc Basically after cable cals i got 4mm2 for live conductors for one of the circuits they wanted me to work out and it is a 36m length run...
  20. Z

    Verifying SWA CPC suitability disconnection times / adiabatic equation

    As you may know looking at some of my posts I've been thrown back in the deep end recently – and don’t have much experience with complicated calculations. As this is the first time I've used SWA to go from the main supply to the primary CCU, and as I'm using the steel armour as my CPC, rather...

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