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  1. The Mains Man

    RCCB making the Zs higher than it should be

    after finding an unexpectedly high Zs on a shower, I narrowed it down to: Zs at input of RCD (RCCB) is around 0.18 as would be expected but the Zs at the output of the RCD is 0.96! Both tests done with 3 lead low test on Megger MFT with 3 month calibration. It is a split load board and both...
  2. Murdoch

    18th Edition & OSG - higher or lower - a bit of fun!

    So we all have to start parting with our hard earned monies CEF have just emailed me an offer of £94.95 (they say no VAT) Which is the cheapest I've seen so far .......... Anybody seen a lower price (or higher) :):):):) EDIT: The bundle isn't for both IET books the OSG guide is the NICEIC...
  3. B

    High ze readings. Even higher zs?

    testing a TNS installation today, found a high incoming ze of 1.14ohms, in my head putbthis down to incoming earth issue as all terminations tight, but when I test any subsequent circuit I’m getting much greater zs readings approx 4.0 ohms. I was expecting high earth loops as my incomer was high...
  4. L

    Nest Pro Installer

    Morning everyone, just wondering if anyone has any experience with being a Nest Pro Installer and what is involved in getting set up and if it was worthwhile, many thanks.
  5. B

    Tungar battery charger

    Saw this on ebay VINTAGE BATTERY CHARGER | eBay - http://www.ebay.co.uk/itm/142209979231?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT Did a bit of research on the net seems it has a mercury rectifier in it. Built in the 1920s. Anyone remember seeing one before? only thing I...
  6. J

    Alphatek tek837 clamp meter

    I've just got the Alphatek Tek837 clamp meter as it seemed a good price compared to others with the same features, does anyone have any experience with this meter, since i ordered it i've learnt it's been sold under different brand names, Metrel tek837, Alphatek tek837, Di log DL6404 and...
  7. M

    Help with sourcing replacement power adapters

    Hey guys I'm new to this forum and looking for some advice from all you guys who know your stuff when it comes to everything electrical. I'm a creative filmmaker so naturally not clued up on adapters and things but I have LED lighting panels we use to light scenes and interviews and things and...
  8. Pat H

    Domestic Upgrading supplier fuse

    Got a job with a 60amp supplier head fuse. Contacted Eon re upgrading to 80amp or 100amp. Their reply is they don't do that I need a qualified electrician!
  9. G

    Earth fault loop impedance

    How does earth fault loop impedance and disconnect time requirements change for 3phase 3 wire 230 volt systems where the phase to earth voltage is 133 volts instead of 230 volts?
  10. J

    d type breakers needing a low zs

    im a 1st year apprentice thats why im asking this question, from what ive gathered the higher the current it takes to trip as in 10 times the rated current etc... for that you need a lower zs than if it was a b type why is that? my thoughts on it is that becuase you have a higher current so...
  11. P

    Full Calculation of Perspective Fault Current - PFC

    I seem not to have access to the professional forums so I post this here: I understand ohm's law and to get a current you use Volts/Resistance (V/R); so if it's Perspective Fault Current (PFC), it's V/R or Volts/Ze; and we divided by 1000 to convert to kA. Yes? Is there a difference when...
  12. A

    Domestic Can towel radiator be upgraded just by switching element?

    A client has a Dimplex TRS120 oil-filled 120W electrical towel rail. The element has packed up and before it's replaced I wanted to check whether the 120W element could simply be replaced with a higher wattage one, e.g. 175W (TR8404), as listed in the Dimplex spares brochure, a couple of lines...
  13. D

    RCDs raising zs values

    Was at a property toady which I've done previous work before including fuseboard change. All i did today was change a few socket plates over for new ones. Took some Zs readings and noticed they were very near the limit of being acceptable ie: 0.92, 0.98 etc. Took a Ze at the board with main...
  14. J

    Will a reading higher than given in 7671 for Zs values be okay if protected by RCD

    I might be COMPLETELY wrong.... but I have recently finished my level 3 in college and I'm sure I was told that if a Zs value is higher than the max reading in BS7671 it's okay if it's protected by a 30mA RCD, so it passes. I sort of remember writing 'satisfactory' on the test form next to Zs...
  15. J

    Rcd x5 higher than x1 reading

    Hi all, just filling out some paperwork from an inspection a couple of weeks ago and just noticed that a x5 reading is 76.4 and x1 is 28.4-not sure if I've misplaced a decimal point or what.. Going to go back and recheck it tomorrow- how can x5 be higher?
  16. M

    Continuity of ring final circuit..... can somebody help please !!!!

    Im currently studying electrical and im up to dead tests. ive reached continuity of ring final circuit on my scenario cd , in therory i understand the procedure and what to do but im a little un sure on finding the mid point on the sockets . please can sombody go threw it step by step in...
  17. S

    8 commercial units, 8 meters on one set of deeds?

    I have been to survey a job and whilst discussing potential options we discussed a 50 kWp system on a barn and a 3 - 4 kWp system for each commercial unit. I feel that because each unit has its own meter and has its own user(s) it should be seen as 8 seperate systems all with the higher FiT...
  18. C

    Grid supply voltage too high!?

    We have a 29.76kw system of REC 240w panels. Feeding 2 x SMA 1500TRL Inverters. Supply is 3 Phase. Input voltage is around 250v constantly, peaking higher at times (we are positioned close to a new sub station). Our electricians/installers have had permission, from DNO and SMA, to raise...
  19. rallyandy

    Spot the mistakes - Billy Bulls**t circuit sheets i think

    I went to look at a hotel today, the first thing is the old boards which have various gaps and 3Ka breakers JB's everywhere, and look at the recorded results !!
  20. A

    Very high prospective fault currents.

    Ze 0.02 giving a PEFC reading of 12.4kA which equates correctly; high but acceptable with fitted 100A BS 1361 supply fuse. However, PSC reading of >50kA. Instrument (Fluke1653B) checks out ok. Any ideas? Will be contacting supplier when I discover who the supply company is.
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