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Connectors for 200V dc

davidwalker2
I have an installation that uses 200V dc (balanced about earth but not earthed). All the installed equipment is direct wired, but I have an application that needs a plug and socket.  I don't want to use the standard connectors that are also used for ac to avoid ac equipment being plugged in inadvertently.  The equipment in question will draw a current around 8 amps and is metal framed, not double insulated so needs an earth.  I would be grateful for any suggestions/ advice.


I am sure that this has been discussed previously, but I cannot find it on the old forum.


Many thanks,


David
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    davidwalker2:
    Again, many thanks for your replies.  The Guide recommended by Graham is very useful and addresses many things we have needed to resolve over the years.  Unfortunately it rather cops out on the connector issue, stating that “the standards required by this legislation [Plugs and Sockets (Safety) Regulations] restrict the use of general-purpose socket-outlet circuits for currents of 13 A or less operating at LV d.c. in relevant parts of electrical installations.”

    For information, on our site the main dc source is a 200A mercury arc rectifier (see my avatar) backed by a lower power solid state supply (40A).  Fuses are BS88 dc types, disconnectors are heritage (1928) open frame, and a couple of modern dc contactors.  Our major problem has been wire colours, red/black on the oldest heritage cabling, brown/blue on later heritage modifications.  We have chosen not to introduce a third combination, the current standard brown/grey and rely on separation, clear labelling and a competent expert workforce.


    David

     




    The intent of the statement about the Plugs and Sockets (Safety) Regulations is aimed at the use of DC in domestic and similar situations for general purpose use - this would perhaps require a change in legislation if widespread small power LV DC were to be used (as opposed to ELV DC)?


    Wire colours have changed again I'm afraid - and this has nothing to do with the Wiring Regulations (BS 7671). The latest edition of BS EN 60445:2017 (any conflicting standards have to conform by its implementation date in 2019) states that for DC systems:


    • L+ - Red (or Blue if it's on a 2-wire Positive Earth)

    • M - Blue

    • L- White (or Blue if it's on a 2-wire Negative Earth)


    Since the Technical Brief was published, ranges of couplers for DC use in data centres are now available. They are to agreed IEC standards too. I wonder whether these would be of use to you?
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  • 0

    davidwalker2:
    Again, many thanks for your replies.  The Guide recommended by Graham is very useful and addresses many things we have needed to resolve over the years.  Unfortunately it rather cops out on the connector issue, stating that “the standards required by this legislation [Plugs and Sockets (Safety) Regulations] restrict the use of general-purpose socket-outlet circuits for currents of 13 A or less operating at LV d.c. in relevant parts of electrical installations.”

    For information, on our site the main dc source is a 200A mercury arc rectifier (see my avatar) backed by a lower power solid state supply (40A).  Fuses are BS88 dc types, disconnectors are heritage (1928) open frame, and a couple of modern dc contactors.  Our major problem has been wire colours, red/black on the oldest heritage cabling, brown/blue on later heritage modifications.  We have chosen not to introduce a third combination, the current standard brown/grey and rely on separation, clear labelling and a competent expert workforce.


    David

     




    The intent of the statement about the Plugs and Sockets (Safety) Regulations is aimed at the use of DC in domestic and similar situations for general purpose use - this would perhaps require a change in legislation if widespread small power LV DC were to be used (as opposed to ELV DC)?


    Wire colours have changed again I'm afraid - and this has nothing to do with the Wiring Regulations (BS 7671). The latest edition of BS EN 60445:2017 (any conflicting standards have to conform by its implementation date in 2019) states that for DC systems:


    • L+ - Red (or Blue if it's on a 2-wire Positive Earth)

    • M - Blue

    • L- White (or Blue if it's on a 2-wire Negative Earth)


    Since the Technical Brief was published, ranges of couplers for DC use in data centres are now available. They are to agreed IEC standards too. I wonder whether these would be of use to you?
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