values

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  1. P

    Max Zs values at different ambient test temperatures

    Hi guys, I'm currently revising for my 2391 and kind of confused on the temperature factors for the Zs values The BBB give Max Zs which are 100% values with a max operating temperature of 70c. The OSG and GN3 give values to 80% which are when tested at ambient temp of 10c according to page 146...
  2. C

    UK Why don't values in the OSG table I1 match those calculated?

    Hi everyone. I am really puzzled by this, but I suppose there is an obvious answer / reason! Anyway, Table I1 in the OSG says the mΩ/m value for copper with a CSA of 25mm2 is 0.727. However, when I calculate the R value using the formula: I get 0.688... Does anyone know why the values aren't...
  3. S

    Continuity values keeps going down.

    So bought a second hand Megger BM233 to practice with as I'm a college student.. So I was just using it on a loose 2.5 cable. Testing on the neutral from both sides . Whilst having the device on the Ohm side. I nulled it to zero by touching the probes. When I do the dead test. It starts off...
  4. P

    Can earth electrode resistance values be too good/artefactual?

    Hi all, Would like some advice on the below. Context: Rural French domestic installation TT system Earth rod is situated inside the property, buried in the concrete subfloor Distribution transformer (overhead supply) is very close, on a pole approx 40 metres from the property I did some 3...
  5. F

    Zs values recorded results.

    Evening everyone, I was taught when carrying out Zs testing to test both L-PE and L-N and record the highest result of the two tests for my Zs column. However, speaking with a friend he informed me that this is wrong as Zs = Ze + (R1+R2) and not (R1 + RN) which is right and never crossed my...
  6. J

    Zs Values for BUSSMANN - ED355 FUSE BS88 355A 415VAC

    Hi All, Can anyone help with calculating a Zs value for the fuse described in the title. The fuse sizes in Fig 3A3(c) of the 18th edition wiring regulations do not have a 355A fuse and jumps from 315A fuse to 400A fuse. I've searched and searched but struggling to find an answer. Any help is...
  7. U

    Do I use zdb or ze when calculating zs values on am2?

    Got my am2 coming up on Tuesday and I know I have to calculate my Zs readings Maybe I’m overthinking this but am not sure if I need to use the Ze (which is apparently given to me) or my measured Zdb from my three phase panel in the equation. I have heard different answers, would be great if...
  8. Q

    Merlin Gerin MCCB Zs Values

    Hi All, We have a Merlin Gerin Compact NS100N Single Phase MCCB I've been asked to find its Max ZS Values and to be honest I cant find anything! This is an from an old MCCB board we are re testing. I put it in google and cant seem to find anything, I know Schneider bought this brand out. But...
  9. Simon-0116

    Cable calcs zs and ze values

    Cable calcs using cable calc app Working out cable size for a workshop. 100m long, 100a supply, mccb 100a zs- 0.23 ohms, in a duct on its own, tt earth on 300ma rcd.- 20 ohms App says 50mm swa which I expect. But if I alter earthing to tncs 0.35 ohms it says max ze exceeded zs of device...
  10. D

    Reason for high electrical field values ?

    Hi. I got hands to a EMF meter (emf-390 v2). I walked around in our house and noticed almost everywhere high electrical fields of 50v/m+. I have noticed power strips have exremly high values of 999v/m+ which are still measurable few meters with over 50v/m. Even if the switch from the power...
  11. M

    help with max zs values please

    hello , can anyone reccomend a free download for max zs values for bs 3871 ct breakers please
  12. E

    Generator Protection and PSCC values

    I was asked to go and take a look at a generator set up by a marquee company yesterday to do some testing. It was a brand new JCB 65QS with 209hrs on it (58.7kva prime). The generator was fitted with a socket pack from the bus bar with 3 x 16a on 30ma RCBO, 1 x 32/3 on a C curve MCB and a 63/3...
  13. O

    UK Max zs Values in the on-suite guide

    Hi all, Just wondering if anyone can shed some light on the max zs values in the OSG, they don’t seem to follow the 1.25 divisor stated in the note on page 126 For example BS 60898 circuit breaker, max zs at 70 degrees is 7.28, following the formula this should be 5.82 at 10 degrees which is...
  14. S

    Vw electrical vacuum control valve n75 - Ohm values

    What is a correct Ohms value for n75 valve on vw 1.9 TDI, 96kw engine? I have like 16 Ohms but if I am not misunderstood on spec it says more than that. Does it mean my valve has malfunction? I checked almost everything else but my car still has delayed boost.
  15. T

    LED resistor values.

    Hi, I am just wondering if you can please help me. I have four LEDs connected to a 9 volt battery. They have little circuit boards in them. They will run between 9 volts and 15 volts. I have them wired up in parallel to a 9 volt battery. They work fine. They are drawing 30mA at 9 volts. So I...
  16. Rockingit

    Z values for fuse to EN60269

    Anyone know if there is a specific list of Z(s) values for a fuse to EN60269? I've just used 5s values for an 88:2 as I figured they'd be pretty close but wondered if there is an actual table anywhere. No biggee. Alternatively, has 60269 been replaced by another standard anyway?
  17. K

    Strange voltage and power factor values and installation issues

    Hi, We have installed 2 meters (each meter is a 3 phase meter) for sub-metering in a residential house (1 phase installation per apartment). One of the meters, after correcting installation, works fine now. The other one, in my opinion measures strange voltage values. We had since the begining...
  18. P

    Zack values

    Hi I was wondering if anyone could help me , I was trying to find the maximum Xs value for breakers 60947-2 and 60947-3 . Does anyone know we’re I can find this information ?
  19. G

    typical earth leakage values

    hi all, If there is such a thing as 'typical' values, what, in your experience would you consider these to be from equipment such as pc's and other IT, washing machines and any other significant sources? thanks
  20. KennyKen

    What’s your countries Max Zs Values?

    I’m intrigued to see the differences in Max Zs values compared with the 18th & NEC
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