This discussion is locked.
You cannot post a reply to this discussion. If you have a question start a new discussion

18th Edition amendment one. Volt drop measurement, who is spreading the rumour we need new testers?

Who is the test equipment manufacturer and/ or importer spreading the rumour that we will need new volt drop testers?


Out of interest I have tried an internet search for volt drop testers than can be used to test UK fixed installations and drew a blank with only testers suitable for use in the USA at lower voltages coming up in the search results along with results for auto electrics.


Andy
  •  "...this has still to be agreed.” is not the same as wording such as, 'there are no plans to include such requirements in Amendment 1 (or any other)'. Time will tell, but it may not be unfounded statements.


    F
  • Volt drop would be a 'live' test anyway. All you'd do is put a load on, measure the current with a calibrated clamp meter, and measure the voltage before and after switching on the load. So no need for a dedicated test instrument at all.
  • I know that my testers don't do all that I want them to do. They don't make the tea and can not receive television as well, or predict racing results. Regarding Volt drop, that can be calculated from tables. Years ago in the time of the incandescent light bulb, if you turned on an electric room  heater or the immersion heater or kettle and the room bulb did not dim so that you could not find the kettle in the kitchen the Volt drop was acceptable.


    Z.

  • Sparkingchip:

    . . . Out of interest I have tried an internet search for volt drop testers than can be used to test UK fixed installations and drew a blank with only testers suitable for use in the USA at lower voltages coming up in the search results . . . 




    The Martindale ET4000 and ET4500 multifunction testers do. Mine will give percentage volt drop either all the way from the substation transformer, or from a point in the installation. The test can be carried out on 110V, 230V or 400V systems. I have no connection with Martindale, other than as a satisfied customer. 


    Regards,


    Alan. 

  • Oh Blinkin' ek, now there's something else to worry about.


    Z.
  • Oh dearie me!


    You certainly don't need a new tester, but the Martindale mentioned above makes it easy by storing the data and doing the maths for you.


    18th Edn says little: check it by measurement or calculation (643.11).


    17th Edn said more inasmuch as it said how to measure or calculate (612.14).


    To remind you, VD is measured by measuring R1 and Rn, and then multiplying their sum by In. If it is inconvenient to disconnect the circuit, you can measure its impedance (using your EFLI tester) at the end of the circuit and subtract the impedance at the origin. You will have done the PSSC at the DB, so you just need to note the impedance and take it again at the end of the circuit. So no new testers required! ?
  • A J.W. practical Voltage drop instructional video.

    https://www.youtube.com/watch?v=hPHLxi9qBH8


    Z.
  • You should not need a video to work out volt drop. The calculation is easy after measuring voltage and current. If it is included with the first amendment proposals, then it is trying to reinforce that electricians should already be confirming it, not entering the figures from a “design calculation” involving the tables from BS7671. 


    Regards,


    Alan.
  • I don't need a video to work out Volt drop, but others such as students or apprentices may benefit from viewing J.W's video. We are not all seasoned experienced electrical engineers on here.


    Z.
  • I have just looked at the Martindale tester data sheet and I am not seeing anything in the specification specifically about measuring voltage drop.


    Perhaps I am wrong, but I assumed a voltage drop tester would allow you to test using a dummy load of 6, 10, 16, 20, 32 or 40 amps so that you can instantly test a standard circuit without having to connect loads actually to the circuit by for example turning all the lights on or plugging in electric heaters.


    Going around and turning on all the lights, turning on all the fixed appliances and connecting electric heaters etc is presumably the real way to test voltage drop using a meter to measure the loaded circuit at each end then working out the difference. So rather than buying a new tester can you just turn everything one and check the voltage with your loop tester as you are measuring Zs? But do you really want to be running appliances such as an electric shower with the cover removed to access the terminals within it to measure the bolt drop?


    But  if the circuits are within the standard circuits specified maximum lengths  in the IET Onsite Guide tables and the Zs is satisfactory for each circuit there cannot really be any point in specifically testing the volt drops, can there? After all there is rarely a problem with voltage drop in UK installations with voltage generally in excess of the 230 volts used for design calculations.


    Andy