max

  1. Rocboni

    Max Zs

    Hello, Having a bit of difficulty completing the below assignment, wondered if anyone can expand on this? Explain in detail the relationship between the Protective Device and the Earth Fault Loop Impedance, Maximum Zs for the protective device and how this is calculated, Maximum disconnection...
  2. michaelw6

    commercial industrial zs mccb 3phase question TN-C-S.

    Im specking a large 480a cable over 160m ive done cable calcs and come up with 2x 120mm 70c armored. now Im trying to work out my max zs...with no avail. my main ze is 0.17 but my mccb is saying max zs of 0.054 and my mccb will not trip... why is it so low? its impossible to get my zs less than...
  3. haptism

    Max distance of fcu from appliance

    Hi, is there a max distance an fcu can be from an appliance ? Im looking to fit a wall heater on a dedicated circuit; I know the fcu needs to be near to the heater for isolation and maintenance ? I cannot find anything to define "near", in Reg 537.3.2 at least. Anyone know ?
  4. B

    Cables In Parallel, Max Load?

    Hi Just wondering if someone could help me out with this one Basically I'd like to know what's the maximum load (single phase) a 4 core 6mm SWA could deliver if cores were connected in parallel SWA in buried under ground and the length is three hundred meters The cable used to supply a 3...
  5. haptism

    Max Zs and (0.8) rule of thumb

    Hi all, could anyone please explain the necessity for multiplying cpd max Zs values (tables 41.2 ect of the byb) by the rule of thumb value of 0.8 ? Is it to allow for discrepancies in tripping times (for example a C type breaker trips between 5 - 10 times its rated current) ? Im assuming that...
  6. P

    Help needed with max demand calculation

    Hello all, i posted this in the electrical theory section but with no responses I thought I would post here as well - since originally posting I have spoken to ELECSA and they have basically said I can use any basis I want to calculate diversity so long as I document what I used and why which...
  7. i=p/u

    max zs results

    Hello, has anyone made up a new handy form filling sheet for the new max zs times??? also the book doesnt do 1A, 2A 4A mcbs? where do i find ? thx
  8. S

    Max Zs on rcbo type c 32a 1667 or 0.54??

    Has anyone any views on max Zs for say a type c 32a rcbo at 80% is 0.54 and 100% 0.68. I am currently testing a collage and all ring circuits are type c and I am exceeding 0.54 and 0.68 this is a TNCS system so to my knowledge table 41.5 in regs which tells us 1667 for 32a rcbo for TT systems...
  9. R

    max amp of cable

    could someone please help me quick its fairly easy, left my regs book at work and cant seem to find the tables online, recieved a snag sheet from a test saying a tp breaker needs down rating from 100a to 80a they are 25mm type of wiring b, ref method b i thought of the top of my head they...
  10. N

    Max Zs of MEM MFL1253 125 MCCB

    Hi Could anyone help with this. Cant find manufacturers data anywhere. Thanks
  11. Soulsurfer

    Max demand etc.. on renovation.

    Hi I am just doing a renovation / upgrade on a small house and as kitchen plus all downstairs was on same ring final I have broken it up into a separate kitchen ring and downstairs ring and renewed best part of the cabling as it was really old stranded earth steel looking junk cable and not...
  12. P

    Max Zs values

    Hi everyone, does anyone know or know where I can find max Zs value for 750A BS88 gG fuses. I did a periodic during a shutdown last week an was rushed of my feet. I can`t find anything on the web and can`t get back in to check the manufacturer.
  13. J

    NICEIC Certification Scheme Max demand on eic for niceic ---

    Morning i have calculated my max demand as 69.6a (sum of mcb's x 0.4) and on my eic i have n/v the main head fuse- but on the sticker it says 60/80a (i know it could actually be 60 or 80 or 100 inside) this is the job i am using for my niceic initial assessment will this be asked about by...
  14. 1capybara

    Table 41.3 Max earth fault loop impedence (Zs)

    The heading of table 41.3 says it shows " max earth fault loop impedance Zs for Circuits Breakers..... giving compliance with 0.4s disconnnect time of 411.3.2.2 and 5s disconnnect time of 411.3.2.3." 411.3.2.2 is for final circuits not exceeding 32A. 411.3.2.3 is for distribution circuits and...
  15. B

    Max Zs amendment 3

    Just going over all these changes brought about by amendment 3 and familiarising myself with the new max Zs and I understand how they are arrived at using Cmin to reduce total by 5% and the question is on a 30ma Rcd is the max Zs still 1667or should Cmin be applied and reduced by 5% ? if not...
  16. A

    Max permissible ZS for rcbo 61009

    So, when I did my 2391 I&t course I was told to use to values in table 41.3 of the regs for max ZS value for rcbo which provide earth fault, and over load protection. Recently a colleague of mine said you should use the value in table 41.5 which states a max permissible ZS of 1667 ohms. I don't...
  17. M

    Max Zs for a 50A BS3871 type 4!

    Can someone help confirm what the max Zs for a 50A BS3871 type 4 Mcb? Am I correct to use the equation 230 / (50xIn)? Using that equation it comes to 0.092. Theres not much help in the regs!
  18. A

    Max length of unsupported flex to a light fitting.

    Max. Distance for an unsupported flex from a clik ceiling rose to a light fitting. Can anyone point me in the direction of the Regulation number?
  19. D

    Max Zs permitted values..

    Hi guys n gals think I messed up my last post as it be gone... Anyhow got a question C32 30Ma 10k RCBO on a standard final ring with the same supply characteristics as ANOTHER final ring off the Db 6 inches from it... Live been going through the O/M manual and found the test sheets and these 2...
  20. L

    max zs table in the osg

    Hi all sorry for this silly question but i cant seem to find the max Zs table for a 10A BS88-2 Fusein the osg. I can find it in the BGB table 41.4 10A = 7.19 ohms and i know to multiply it by 0.8 (7.19 x 0.8 = 5.75) for rule of thumb but i would like to find the right table in the osg
Best EV Chargers 2025
Best EV Chargers by Electrical2Go! The official electric vehicle charger supplier.

OFFICIAL SPONSORS

Electrical Goods - Electrical Tools - Brand Names Electrician Courses Green Electrical Goods PCB Way Electrical Goods - Electrical Tools - Brand Names Pushfit Wire Connectors Electric Underfloor Heating Electrician Courses
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc

TrueNAS JBOD Storage Server

YOUR Unread Posts

Daily, weekly or monthly email

Receive a daily, weekly, or monthly email containing a digest of new and recently updated threads.
UK Tiling Forum | Tilers Forums
UK Tiling Forum by Tilers Forums UK
Plumbers Forums | Plumbing Advice | Gas Forum
Electrician Tips from Professional Electricians
JBOD Forums: a forum for JBOD storage server advice
JBOD Suppliers: JBOD Storage Server Supplies
Back
Top