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1970's mechanical time clock controlled 3 phase economy 7

wessex
Current set up. 3P+N intake taken to 4 100A single pole connectors which have been sealed.. L-N taken from connectors to mechanical time clock. A 3 phase supply is then taken to two 30A 3P BS3036 switch fuses. Post side the switch fuses is a 3P, 415V coil contactor, both housed in separate pressed steel enclosures. A number of 6mm ish single core insulated and sheathed cable are taken from the contactor to a mixture of one and two way BS3036 DB. Post side of the switched fuses, from the blue phase a feed is taken, linked then taken to the time clock, switched contact maybe. Then from the time switch a feed is taken to each contactor via a FCU possible for the coil. Another cable is taken to each contactor, but has no such FCU. The control wiring is done in 4mm ish insulated and sheathed single cores. The control gear, switch fuse and contactor have developed operational issues and need replacing. Not sure who owns the switch fuses and contactors. A very untidy installation, cables appearing to go everywhere.

I was wondering what the replacement options where given the three phase is only used for night storage heaters so timed controlled would have to be kept, no daytime boost.

Your thoughts please.
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    Sorry, I'm confused (there seems to be far too many contactors and the mention of a 415V coil worries me). Do you have a picture?


    Normally the supplier would be responsible for the timeswitch that determined whether the peak or off-peak tariff was being charged and usually the first line of contactors too (them being sealed would seem to confirm that) - but there have been other arrangements.


      - Andy.
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    Can I suggest that  Wessex reads the post replacement  of contactor box as posted a few weeks back it MAY be helpful in helping you decide what to do as it seems very similar to your question
  • 0
    Ask for a smart meter to be installed, hopefully you will end up with a four pole main switch supplying the tails from a new relay.


    But the metering services guy may just run away muttering about having to ask the office for advice,  as happened on a job I went to several weeks ago. 


    Andy B
  • 0
    Thanks for the responses.

    No pictures. Frankly it's as mess. The switch fuses and the enclosures for the contactors are not sealed just the single pole connectors. Fusing in the one side of contactor control is not good. One side effectively being protected by intake protective device and connect by cable approximately 4mm2. Post switched fuse blue (L3) being linked means that if only one switched fuse is turned off, the line is still live being fed by the other switched fuse.

    The meter has recently been changed, but not smart.

    I think the best option is as Sparkyingchip suggests and remove all existing switch/control gear and have a 4 pole main switch provided from which I can provide new timed control distribution which would also replace the one and two way DB's. Just need to check the tariff arrangements.
  • 0
    The relays connected to smart meters I have seen actually have a neutral switched by the meter to operate them.
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    I have seen actually have a neutral switched by the meter to operate them.



    I  think that's the traditional UK arrangement - but it gets rather messy when the contactors are on the comsumer's (BS 7671) side (fused N and switched N aren't really what we're comfortable with) - although it does still allow the entire consumer's installation to be isolated by the main switch (presuming you don't need N to be isolated - like in a TT installation). The French approach of the DNO just supplying a pair of voltage free contacts to the consumer (who then uses them in their own control circuit, entirely after the main switch etc) does seem cleaner somehow.

      - Andy.

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