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
  • Locked Locked
  • Replies 119 replies
  • Subscribers 32 subscribers
  • Views 17548 views
  • Users 0 members are here
Options
You may also be interested in
This discussion is locked.
You cannot post a reply to this discussion. If you have a question start a new discussion

Type A rcd . EICR coding ? etc

aligarjon
Hi Guys.   Not been on for a long time, just had a bit of a search and couldn't really find anything so thought i would ask and see what you all thought.


1.  Are we or will we be coding type AC rcd's if there are LED's or induction hobs, lots of electronics  etc  present.

2. How much DC leakage does it actually take to saturate an rcd and cause  problem?

3. How much does a standard LED lamp or induction hob  leak ?

If we test an AC RCD with no load and it's fine then re-test it with all LED lights, induction hobs etc turned on and it operates correctly could we then say that it is ok with a note on EICR  OR EIC if installing any of the above.  


Obviously also on an EICR if the RCD then doesn't operate with it all on it becomes a C2 ?


Any thoughts



Gary
Parents
  • 0
    I have spent a couple of hours yesterday experimenting with RCDs, rectifiers, and various degrees of leakage from the rectifier DC to Earth. The interesting effect is that the leakage seems to cause an increase in trip time, rather than a failure to trip when using my MFT to test. A different RCD tester shows much less effect although they both give similar results with a normal unloaded circuit and RCD. I am using a 1kW lamp load on the rectifier output, so the RCD transformer is actually having to do some work, rather than the unloaded condition. This is an attempt to demonstrate a real circuit rather than the unusual test condition of zero load.


    DC current produced by a 10k resistor to Earth has little or no effect. A 5k resistance increases trip time to a second or so, but does no prevent a trip. This is one make of RCD, BSEN 61008-1, I will try some others and other currents when I have got some more parts, more power resistors of various values. I have yet to add a smoothing capacitor to the DC, and I will have to move the lamp to be AC powered otherwise I will need a very big smoothing capacitor to get a low ripple supply.


    The fault I am simulating is undoubtedly unlikely in any real product, as 5k from a creepage distance of 3mm is hard to imagine, but that seems to be the point behind these diagrams in A53.1. Further testing to follow.
Reply
  • 0
    I have spent a couple of hours yesterday experimenting with RCDs, rectifiers, and various degrees of leakage from the rectifier DC to Earth. The interesting effect is that the leakage seems to cause an increase in trip time, rather than a failure to trip when using my MFT to test. A different RCD tester shows much less effect although they both give similar results with a normal unloaded circuit and RCD. I am using a 1kW lamp load on the rectifier output, so the RCD transformer is actually having to do some work, rather than the unloaded condition. This is an attempt to demonstrate a real circuit rather than the unusual test condition of zero load.


    DC current produced by a 10k resistor to Earth has little or no effect. A 5k resistance increases trip time to a second or so, but does no prevent a trip. This is one make of RCD, BSEN 61008-1, I will try some others and other currents when I have got some more parts, more power resistors of various values. I have yet to add a smoothing capacitor to the DC, and I will have to move the lamp to be AC powered otherwise I will need a very big smoothing capacitor to get a low ripple supply.


    The fault I am simulating is undoubtedly unlikely in any real product, as 5k from a creepage distance of 3mm is hard to imagine, but that seems to be the point behind these diagrams in A53.1. Further testing to follow.
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