Rules and Guidelines
Want to participate in the discussions? Please read our Community Rules and Guidelines. Need some help? Visit Support and Answers.

  • State Not Answered
  • Replies 15 replies
  • Subscribers 36 subscribers
  • Views 424 views
  • Users 0 members are here
Options
You may also be interested in

Apparent voltage on plastic service head

Tolly

What are your thoughts on this please?

Using the TIS810 contact volt stick, you can see (no audio) that no voltage is indicated on the isolator, tails or meter, but there is (by flashing red and vibrating) on the plastic service head/fuse - the tester is supposed to activate at 50-600v. The relevant DNO came and tested it, and stated there's no more than 0.4v on the head (though I don't know about the tester they used). 

Parents Reply Children
  • 0 in reply to Sparkingchip

    I see that at ~3:24 he proves live incomer with a test lamp first ;-)

    The problem that Father in Law had was that there was coupling between a true live and his isolated circuit (not sure what voltage he was working on) and that it was still capable of lighting a neon tester that was in use at the time. He needed the test lamp to show that there was no live power (this will have been before RCD leakage/shock protection being common).

    It's still a useful video though.

  • 0 in reply to Philip Oakley
    Philip Oakley said:
    I see that at ~3:24 he proves live incomer with a test lamp first ;-)

    A two pole tester shows there is a voltage difference between the probes, but not which probe actually has the highest voltage on it, it could be either of them.

  • 0 in reply to Philip Oakley
    Philip Oakley said:
    The problem that Father in Law had was that there was coupling between a true live and his isolated circuit (not sure what voltage he was working on) and that it was still capable of lighting a neon tester that was in use at the time.

    Which is why many voltage testers have a switchable load, to reduce the impedance of the tester,

    The high impedance load stops the RCD tripping, but creates ghost voltages.

    For example Fluke T-series testers provides single and double pole voltage indications and a switchable load, requiring two buttons to be pressed simultaneously.

    • Single-pole phase test offers fast identification of live conductors
    • With 4 ways to indicate the presence of voltage – LED indicator, LCD display, audible tone or tactile feedback, always know if hazardous voltage is present
    • Switchable load: avoid display of ghost voltages allowing you to draw more current from the circuit under test and avoid trip residual-current devices (RCDs)

    www.fluke.com/.../fluke-t150

Community Rules & Guidelines