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Light sockets

Former Community Member
Former Community Member
Something that has puzzled me for years.


Bayonet cap and Edison screw light bulbs can be removed without tools thus exposing potentially live terminals and presenting a distinct shock hazard.  made worse by the fact that you often need to stand on a chair to remove the bulb.   There are millions of these installed yet the regs seem quite happy with the situation.
  • 0
    Its quite a bit more than 100 years, say 111 since the first BS standard covering them, and all the early versions should be out of copyright (70 years since first published, as individual authorship is not ascribed).


    As a point of note BS52 was the standard  number from about 1910 to mid 1981, when it became 5042,  as the standard got updated without changing the number, however the 1933 edition is the earliest of many outdated versions you can get from the BSI in PDF format.


    Actually compared to the standard for lamp holders, the wiring regs are positively a model of stability.


    BS52:1910 1st edition

    BS52 1927 revision 1

    BS 52:1933 rev 2 Bayonet lamp-caps and metal cased bayonet lampholders not exceeding 250 volts

    BS 52:1936 Bayonet lamp-caps. Lampholders and lampholder-plugs (B.C. adaptors) for voltages not exceeding 250 volts

    BS 52:1941. -"-

    BS 52:1952 Bayonet lamp-caps. Lampholders and lampholder-plugs (B.C. adaptors)

    BS 52:1963 Specification for bayonet lamp-caps lampholders and B.C. adaptors (lampholder plugs)

    BS 5042-1:1981 Specification for lampholders and starterholders. Bayonet lampholders

    BS 5042:1987 Specification for bayonet lampholders

    BS EN 61184:1995 -"-

    BS EN 61184:1997, IEC 61184:1997 -"-

    BS EN 61184:2008 -"-

    BS EN 61184:2011 -"-

    The latest is BS EN 61184:2017 Bayonet lampholders


    And its already been reviewed again, so clearly things are changing fast in lampholder world....

    A similar thread of documents exists for edison screw lampholders, the connections for florry tubes, ELV lamps, aircraft lamps, linear lamps..

  • 0
    Is there nothing in the regs that says live parts must not be accessible without tools?

    Sort of - but there are specific exceptions for ceiling roses, cord operated switches and BC & ES lampholders. (See BS 7671 reg 416.2.4)

      - Andy.
  • Former Community Member
    0 Former Community Member


    Neither type is meant to be used on more than 250 volts.

     


    Even though the new harmonized voltage permit supplies up to 253 volts


  • 0
    dcbwhaley:


    Neither type is meant to be used on more than 250 volts.

     


    Even though the new harmonized voltage permit supplies up to 253 volts




    I suspect that they mean a NOMINAL 250 volts.

    I must admit that I have used on a standard UK mains supply, switches marked "240 volts AC" Even when the the supply voltage was 245 volts at the time of installation.


  • Former Community Member
    0 Former Community Member


    I must admit that I have used on a standard UK mains supply, switches marked "240 volts AC" Even when the the supply voltage was 245 volts at the time of installation.


    That would be a C1 in my book :-)


  • 0
    Do not even suggest it, out there somewhere some jobsworth is licking his or her pencil with glee.


    (and in the mean time advocating  such poor inspection practices  invites the wrath of Davezawadi... I agree with that, but may be less terse. )


    regards mike
  • 0
    I am afraid that I cannot understand why you were given a job for which you were neither qualified nor suitably trained. To do so would appear to me to be contrary to the "Electricity at Work" regulations, and therefore illegal! However, stranger things have happened. I do sympathise that sometimes one can be given jobs which may not obviously be quite complex, but the opposite can also be true. I was once given a rack full of electronics and told to get it through the EMC regulations (which were new at the time) simply because I knew a lot more about RF and EMC in general than anyone else, and the job was close to impossible anyway. After most of a complete redesign, it did pass, but they were not at all happy about the cost and complexity of what was required!


    In reality, lampholders have never been a great source of danger for a couple of good reasons: They are normally full of lamp, and it is normal for most people to turn the lamp off before removal because otherwise, one used to get serious burns! The greatest danger has been removed by the change to LED lamps, they are no longer glass and therefore cannot easily be broken exposing live parts. Now, I bet you didn't think of that!


    The whole EICR thing does frighten many people with codes and a report which most cannot understand. I have tried to explain why your Sister's one may be worse than it looks in the other thread. However as your PAT experience, the quality of many needs serious improvement. I think the idea that EICRs treat dangers in an "everyone is an idiot" way is inciorrect, it should not be that way, that is what happens when idiots get to carry them out!


    Here is one for Mike: OK BNC, bayonet connector (which it is) but so is a C connector, just bigger!
  • 0
    Here is one for Mike: OK BNC, bayonet connector (which it is) but so is a C connector, just bigger!


    Oddly (like the threaded HN ) the type C RF connector  is another Amphenol special  I've never had to use in anger. 

    I agree without a sense of scale a C looks like a BNC but the power handling is more like that of a 7-16 DIN - of which I have used a few on RF base-stations and so on.  I even have a badly toasted one somewhere as a reminder to respect the power of RF into a mismatch in systems where the PA does not fold back, but keeps on giving.


    On the subject of touch voltages and things that look like a BNC but are not quite the same there are special safety versions of the BNC made for high voltage instruments like vacuum gauges that have a few kV on the wire (example ) The idea is you can take the cable off the wrong end of the rig by mistake and put your finger over the ends and not get bitten. Probably. For very good reasons a normal BNC cable will not plug into one.

    Mike.
  • Former Community Member
    0 Former Community Member
    davezawadi (David Stone):

    I am afraid that I cannot understand why you were given a job for which you were neither qualified nor suitably trained. 


    In reality, lampholders have never been a great source of danger for a couple of good reasons: They are normally full of lamp, and it is normal for most people to turn the lamp off before removal because otherwise, one used to get serious burns! The greatest danger has been removed by the change to LED lamps, they are no longer glass and therefore cannot easily be broken exposing live parts. Now, I bet you didn't think of that!


    The whole EICR thing does frighten many people with codes and a report which most cannot understand. I have tried to explain why your Sister's one may be worse than it looks in the other thread. However as your PAT experience, the quality of many needs serious improvement. I think the idea that EICRs treat dangers in an "everyone is an idiot" way is inciorrect, it should not be that way, that is what happens when idiots get to carry them out!


    Here is one for Mike: OK BNC, bayonet connector (which it is) but so is a C connector, just bigger!


    I was sent on a training course for the PAT.  Which was boring but not as boring as testing brand new IEC leads.

    One problem with lampholders is that if the bulb fails it is not always obvious whether or not the holder is live.  Especially if it has two way switching..


    The whole"regs" business worries me.  It seems to be a method of allowing people with no deep knowledge of electrical engineering to do a job they don't fully understand safely.  That might be commendable but it bothers me that the answer to "can I do so and so"   is"no  because it is verbotten by reg 1123"; rather than "no because the resultant current would be too high"


    My daughter thinks that it is great that the inspector errs on the side of caution because she is frightened of electricity


    And here is one for you:  what does BNC stand for?


  • 0
    dcbwhaley:

    And here is one for you:  what does BNC stand for?


    mapj1:

    To be fair you can drive a 1920s car on the road here, and maybe changing pre-synchromesh gears is a bit fiddlier, but the operation of the basic 4 cylinders gas clutch and brakes and all that  are much the same.

    Bollack, Netter, et Cie. A former colleague has one and it is delightful.

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