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EV CHARGING EQUIPMENT

I am hearing from my network of contractors, that have actually read the new 722, that they have been asking charging equipment manufactures for documentary proof to comply with Note 5 of 722.411.4.


They are getting knocked back for asking or in one case a Declaration that says the particular device complies with BS 7671. I think that is wrong to declare that as BS 7671 is an installation safety standard and not a product standard. I believe that as a minimum the equipment must comply with the Low Voltage Directive and be CE marked. I also believe that manufacturers have to issue a Declaration of Conformity. 


BS 7671 722 has numerous references to the various standards required such as BS EN 61851 that the equipment must comply with. I am thinking it may be illegal to offer the sale of equipment that does not comply with the Low Voltage Directive and is not CE marked?


I am hoping the countries top man of equipment safety standards, Paul Skyrme , sees this post and will come on and give us his expert view?


Has any forum member asked for a Declaration of Conformity from EV charging equipment manufacturers and received one?

  • Sparkingchip:
    095a3a5017d303e18d6880604521b152-huge-55cb8651-471c-4290-a32a-9b3e1fa4ebfa.jpg


    I had the diagram that Graham Kenyon posted in another discussion in mind.

    https://communities.theiet.org/discussions/viewtopic/1037/25732?post_id=138070#p138070


    Andy B.

     




    All we need to simulate that scenario is a battery and two bits of wire.
    8da6e58ead4d00263811369f76734aab-huge-20200410_103726.jpg

    If you have a multimeter and some resistors to hand you elaborate it a bit, but in essence isn't that the scenario?


    Andy Betteridge 

  • You are right Mike that should be mA not ms in the first paragraph, typical first draft I am afraid. I didn't mention another interesting thing either, and that is that switching the DC on, or resetting the RCD with it on also usually causes another trip, as the current edge obviously causes an inbalance and fires the mechanism. I need to find some other makes of RCD, I have never taken one of this type apart although have used a lot, and have found them particularly reliable. As far as the PSU goes, as there is no load and I put the PSU in the neutral connection there is also no mains voltage difference. The Megger obviously applies the live to earth to get the fault current, and so there is no great danger. Also the PSU is pretty robust anyway, with some capacitance across the outputs, so I don't expect trouble. The only problem I have had with one of these was due to battery charging for long periods at maximum output, the output current sense resistor changed value upwards making the meter reading and current limit rather unsatisfactory (and only 6A too into a 100AH battery so connected a long time). These RCDs are comparatively cheap and from China (isn't everything) and may be from the same factory as some other makes, they are a massive player in the market.


    Looking at the results it appears that this type would be fine in a car charging point, there is not a DC problem at 20mA, and they are more than fast enough to give excellent protection although supposedly "only" to 61008-1.
  • Dave, thanks for that, but  I am a little puzzled by your units

    DC + 18ms and DC - 7.5ms. So all passed with flying colours, trip times about 20ms at 30 mA all round. 10 MA of DC changed the AC 180 to 21 mA and DC+ to 12 mA




    Are these ramp tests, results in mA RMS at time to trip, or times in milliseconds ?

    Either could make sense in the context but imply subtly different things.


    In  any case I am heartened that you too see the blinding current is comparable to the trip current , as that backs up my observations - so 20mA may pull a 30mA RCD slightly off beam on a 30mA test, but it will still fire at a fault current of 100mA, and still needs a jammer comparable to the higher test current to blind it.


    The failure to trip on a supply with a PSSC of <16 amps, tells me this is an electronic RCD and internally there is a fairly chonky actuator coil pulled in by a power transistor or triac, not a delicate hairspring loaded mechanical balance. The actuator current needed to fire ones of this sort can be several amps, and the internals are not as fine or as fussy as the traditional passives.


    Please take care not to burger what looks like a decent PSU, - note that at the moment of opening, you do not know if the L or N arc extinguishes first, so there is a risk of a mains voltage or part of it appearing on the PSU for a short time if the contact with the PSU accross is the one that opens first.

    Also,  even with the volts low, you are shunting the N sense coil with the unknown output impedance of the PSU - which should be quite low and may give some imbalance to begin with.


    If there is a known series resistance, say 100 ohms,  (even an old kettle element or something would do) then the fault current if subjected to mains is limited, and the current share between coil and PSU is very much in favour of the coil at a few milli-ohm versus the PSU and resistor combo.


    I have also spoofed an LNE with a fake E and a very local NE bond for such tests, from an L and N only - so upstream RCDs are not affected. But of course only after double checking polarity is right.


    Perhaps I too need to take a pic, but my set  up is, shall we say, rather more agricultural, and I'd want to tidy up first, or folk will chitter about the exposed live bits.


  • 095a3a5017d303e18d6880604521b152-huge-55cb8651-471c-4290-a32a-9b3e1fa4ebfa.jpg


    I had the diagram that Graham Kenyon posted in another discussion in mind.

    https://communities.theiet.org/discussions/viewtopic/1037/25732?post_id=138070#p138070


    Andy B.

  • Andy


    Yes I have done that but that is Line to earth.
  • I can confirm that a 200 mA DC current can trip most types of RCD, just try doing a R1+R2 test with a RCD in the circuit ?
  • David


    I am surprised that a Type AC will still trip at 150mA with a 100mA of DC injected. I will have a go at measuring the DC injection on my old Robin 4120DL loop tester. It locks up RCDs but not RCBOs. It would suggest that RCBOs have a higher DC immunity than RCDs. My DC clamp meter only goes down to 100mA so my test may not indicate anything.
  • This is the setup
    7ac56123aa4c791944a3bad99b57e882-huge-20200409_1642081.jpg

  • Mike

    I have tested one 30 mA so far. The results are interesting, particularly that I couldn't make it work on a 250W isolating TX with TN-S output at all, PFCC 16A. So a bit of wiring to give me a non-RCD protected 13A socket, and things got better. I used a Megger MFT 1552 tester which gives 4 options for the delta In test, 0, 180 degrees and +,- DC. I used a lab supply with CC output strainght across the N of the RCD, no Rs and Cs for me! DC current measured with a Fluke multimeter as below the PSU meter resolution. The RCD (I will not reveal the make yet) was brand new supplied in a 18th ed metal CU. First test at 0 DC although all the equipment connected gave (30 mA ramp) AC 0 12ms, AC 180 7.6ms,DC + 18ms and DC - 7.5ms. So all passed with flying colours, trip times about 20ms at 30 mA all round. 10 MA of DC changed the AC 180 to 21 mA and DC+ to 12 mA,Others much the same, but results very  repeatable. 20mA DC not much change. 30 mA DC stopped AC trip altogether (both phases) and DC-, but DC plus still tripped at 18ms.


    Next change to 5 delta In (150 mA). Here up to 100 mA of DC made little change on AC test, I haven't done DC yet as SWMBO is wanting a hedge trimmed! I will look out some others to see what they do, but not exactly as expected for a EN61008-1 RCCB (80A).

  • Sparkingchip:




    Chris Pearson:




    Sparkingchip:

    If you have become an installer and have gained approval to fit specific chargers, how much choice are you going to give potential customers?




    So when you go out to buy your EV, how much choice do you get in the M-B dealer, or the BMW one, or the VW one, or ...


     




     

    So if you go to the car dealership and order your new car along with the installation of an EV charger at your home how much choice are you going to get?


    I cannot help but think that many people will just get what the EV charger the installation company and car dealership wants to install, rather than maybe what is best for the customer.


    I cannot imagine many people ever ask for a declaration of conformity before placing their order for the car, the charger or anything else associated with them. I can also imagine that those who do are quite possibly considered a pain in the butt.


    Andy B.

     




    Such as a “free” 3 kW charger rather than a more suitable 7 kW charger.


    Andy Betteridge