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RCD types

Is it just me or are RCD types starting to get silly. After the EVSE discussion I've looked at the data sheets for a couple of manufacturers and collected the following list of RCD types:
  • AC

  • A

  • A EV

  • A KV

  • U

  • F

  • B

  • Bfq

  • B+

  • B NK

  • B SK

  • R (for x-ray/CAT supplies)



Plus 'delay' types of:
  • (none) - instantaneous

  • G short delay (10ms)

  • S proper delay/selective


I suspect type U might now be obsolete, and  Bfq and B+ from one manufacturer might be the same/similar as B NK and B SK from another, but it's starting to smack of people just making things up as they go along.


Anyone found any more?


   - Andy.
  • If U was for universal then it is definitely obsolete ?
  • I don't think it's "just you"!    Thank you for introducing me to several I hadn't yet seen.  Remarkable.  I suppose there is a point to some (all?) but it's a fast-changing set, and it's hard to see it as efficient to have the number of separate products that's entailed by (all the types)*(2 or 4 pole)*(4 or more In ratings)*(1 to 3 I{\\Delta}n ratings)*?   Some that are just limited versions of others, such as F vs B, might be able to go if the price of e.g. B were to drop due to greater use of them. There's then the question of how many are defined in standards rather than just from one or a few manufacturers. Doubtless the US and surroundings have a totally different set (it's a different approach, more content to be voltage dependent). 

  • It does seem a while since we thought "A or AC, Standard timings  or delayed?" and not much more, life has become more complicated and we`re getting overloaded with info. Our first "regs" were 4 pages of A4 cos we realised Electrickey might be dangerous, now look - a big book with loadsa references.
  • I agree that all these different types are confusing and probably unnecessary. We need a range of delta In, and somewhat time delayed types, and possibly DC sensitivity, but the others are just slight variations of these basic categories. The Xray and CT scanner types are generally of a significant current rating and it is dubious as to whether these need RCD protection at all, even if they are fed from sockets. In fact we have little statistical information as to whether RCDs reduce fatal accidents at all, with the possible exception of some gardening accidents. A useful analysis back over perhaps 20 years should show a statistically significant reduction in electrical deaths, and fires, but in reality probably show nothing. Along with this goes a change in lifestyle where more equipment is used by uninformed people outdoors, the baseline should be the number of deaths in caravans, because these have had RCD protection longest.


    The use of EFCIs (Earth fault circuit interrupters) in the US should also show a reduction in fires, and the statistics I looked at have disappeared form the net for some reason. There are some for various states, but a big job to correlate, particularly given differing reporting regimens. The deaths from electric shock on 115V in the States is very low anyway, and normal people do not play with 230V circuits very much (although often used for high consumption appliances) . Surely there must be a measurable effect somewhere when we have spent so much money on supposed protection measures? If there is no effect, why are we supposed to spend more money on obviously useless so called "protection" from our closest friend? I call electricity that because life without it would be very difficult indeed, and the poor  living standards in rural Africa attest to this, from personal experience.
  • Point well made David. I guess that we have just become accustomed to providing RCDs and it would grate with us if we went back to the 80s when RCDs were only a feature of TT systems and perhaps a socket at the back door. I am sure many sparks can point to some dramatic example of the benefits of RCDs. Mine relates to the electrocution of a young Queens University student who had gone to a well known burger joint in Belfast. The hand wash/dryer had been vandalised exposing live wires. There was a delay in attending to the issue by the management with the result that a young woman at the very gateway to life lost her future and plunged her family in to the depths of despair. The burger joint immediately   installed RCD protection to all their wash rooms across the U.K. Too late for one family but at least for a few quid extra it might spare grief for others.

  • AJJewsbury:

    Is it just me or are RCD types starting to get silly. After the EVSE discussion I've looked at the data sheets for a couple of manufacturers and collected the following list of RCD types:



    • AC

    • A

    • A EV

    • A KV

    • U

    • F

    • B

    • Bfq

    • B+

    • B NK

    • B SK

    • R (for x-ray/CAT supplies)



    Plus 'delay' types of:
    • (none) - instantaneous

    • G short delay (10ms)

    • S proper delay/selective


    I suspect type U might now be obsolete, and  Bfq and B+ from one manufacturer might be the same/similar as B NK and B SK from another, but it's starting to smack of people just making things up as they go along.


    Anyone found any more?


       - Andy.

     




    I don't know about being "silly" but the subject of the many different R.C.D. types is definitely getting very complicated and confusing. I've given up on juts how they all technically vary.


    Z.

  • Just go by the manufacturers recommendation. In a recent GSHP installation I mithered the manufacturer to death until I got the 'We recommend that Type B RCDs are fitted to our kit'..

    That was good enough for me, and I managed to get an CHINT 2 POLE 80A Type B RCD for around £107 inc vat.

    Now, because Type A rcbos have become much cheaper - they are even cheaper than conventional Type A/C ones from the likes of Wylex & Hager - , especially the 'Fusebox' brand, I fit these as standard on any cu change jobs I do.

    As for Type F etc, these are pretty highly specialized and stupidly expensive. In my realm of work, I don't think they have any application so far.