The IET is carrying out some important updates between 17-30 April and all of our websites will be view only. For more information, read this Announcement

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

  • State Helpful Answer
  • Replies 33 replies
  • Subscribers 39 subscribers
  • Views 1044 views
  • Users 0 members are here
Options
You may also be interested in

Is the UK the only country that continues to permit and deploy TN-C-S earthing systems?

Philip Oakley

In a discussion about Diverted Neutral Currents, an contributor (Australia I think) suggested that the problem was that it (DNC) is unique to UK.

I'm not that well versed in international systems of earthing, but it's my understanding that while part of the diverted neutral current problem is because of PME (Protective Multiple Earth), and PEN (Protective Earth and Neutral). And that the the problem is likely to be common to all systems, because there is only one planet earth/ground and we all have to be careful with it when latent and patent faults abound.

I suspect part of the issue is that different folks hear different parts of the story and then project the aspect that's different from their system onto the UK system (given we are reporting it).

Is PME / TN-C-S special to UK?

(discussion was in a Youtube video on ' Loose Neutral Fault Explained')

 

Parents
  • 0

    Just updated the numbers

    Going through this discussion one of my takeaways is that no one has quoted any serious injury or death from open pen faults in the UK. There are about 1 million home ev charge points installed in the uk. Assuming that at least 900,000 have open pen detection and open pen detection adds £100 to the price, that means the public have so far spent £90 million protecting against a problem that hasn't caused any serious injuries so far. Is this actually a proportionate reaction to the risk. The biggest benefit or downside of open pen detection is that it's showing how poorly UK supply voltage is managed at the moment, with local supply networks failing to deal with massive changes in demand or moving to surplus.

  • 0 in reply to Alan B

    I suspect that adding an open PEN detector to a wall charger costs a lot less than that.  It will already have a microcontroller, and relays to cut the power to the car.  All they need to add is a way of measuring the L-N, L-E and/or N-E voltages, and a bit of software.

  • 0 in reply to Simon Barker

    But the point is valid - even if was free and all  it did was add 15 mins of labour to the installation and commissioning time, it is a non-negligable cost .and that money will come from not doing something else instead. Which may be something trivial like a safety improvement to the hot water system or skipping a service on the car, or something really important like drinking an extra few pints on Friday that affects the nations mental health.

    Mike 

  • 0 in reply to Alan B

    I have to admit that my initial feeling was that 1M EVCPs was a lot, but there are more EVs.

    In terms of risk, when did your DB last trip? Are all those fuses/MCBs/RCBOs really necessary?

    What price a life? I think that we have discussed this in the past and arrived at the conclusion of £1M.

    Fuses and MCBs also protect against the risk of damage to property, which helps to justify their expense. Do open-PEN devices do that?

  • 0 in reply to mapj1

    What labour?  Having checked with the manufacturer's web site, my charger has a dedicated chip on its motherboard.  The installer doesn't have to do anything to make it work.  No earth rod is required.

Reply Children
No Data

Join us to get the best from IET EngX.

Joining EngX lets you personalise your experience so you stay up to date on the topics that interest you, plus you’ll be able to make connections who are looking to collaborate, exchange ideas and more.

Join us Not now

Community Rules & Guidelines