Photocell and time clock for outside lights wiring

Discussion in 'Electricians' Talk' started by Bradley6969, Nov 7, 2018.

  1. Bradley6969

    Bradley6969 Member

    hi, I’m looking at putting some outside lights at my house but am looking at wiring them through a 24 hour time clock and photocell so I have the ability to set the timer so the lights come on a bit earlier in the winter but am unsure how to wire them does anyone have a drawing or could explain I know you wire the photo cell and timer in series but not sure how to do it
  2. Sparkielev

    Sparkielev Well-Known Member

    Why bother with the photocell just use the time clock most are just supply in and load out
    seneca likes this.
  3. eric the fish

    eric the fish Member

    Check out a SANGAMO Solar Compensating time clock, (SMQ550) a bit pricy but automatically adjust for change in daylight and has battery backup. No need for photo cell, simple to wire up.
    Three terminal connection. Power IN,& switched power OUT (Neutrals common)

    Hope this helps

    E the F
  4. Bogle Crag

    Bogle Crag Active Member

    I have used the Sangamos, on quite a few jobs and found them robust and reliable, if you are comfortable with programming one of these has an astronomical clock in its software as well as many other features
  5. HappyHacker

    HappyHacker Active Member

    Wire the photocell from the time clock and then from the photocell to the lights. Set the time clock to the start and finish time you would want the lights to come on/off and the photocell will only turn the lights on when it is dark. The photocells usually turn the lights on for a short time when power is applied to them which may be an issue.

    The Sangamos are excellent though expensive.
  6. buckeroo82

    buckeroo82 New Member

    I did exactly that, to avoid having to change the time clock every week as the nights get darker (and lighter come spring). Timer is set to on between 3pm and 11pm so they go off at 11pm regardless and on anytime after 3pm when it's dark enough.

    As #5 said wiring wise, it's as simple as taking supply to timeclock first, then from load side of timeclock to photocell permanent live, then switched live from photocell to lights. I've also got a switch (between photocell and lights) so I can manually switch off easily. I couldn't work out a way of overriding them to be on with a switch but that situation would only be when it's daylight so don't think there'd ever be a need.
  7. Bazza

    Bazza Well-Known Member

    This will do waht you want

    Not only a time switch but it has Night economy mode: - Unit can be set to turn off after a period of time rather than run from dusk to dawn.
    It also automatically adjusts for seasonal changes in light levels.
    at £25 what's not to like?
  8. Magicspark

    Magicspark Active Member

    Use a volt free contact time clock so you can take the SL from photocell to one side of the contact and from the other side of the contact out to the lights. This way you don’t have the issue of the lights flashing on for a few seconds when the photocell/time clock kicks in.
  9. Bradley6969

    Bradley6969 Member

    Thanks guy so how will the lights come on earlier if it isn’t dark for photo cell to turn them on? Say I set the time clock for lights to come on at 4pm but it’s not dark till 5pm
  10. Bradley6969

    Bradley6969 Member

    Or if I set timeclock to 4pm the lights will come on when it gets dark at 5pm then I can set till when ever? If I want to change this I’ll have to go through a contactor and over ride the photocell?
  11. peter palmer

    peter palmer Well-Known Member

    Not at all, you need a timer with a set of contacts that aren't connected to the live input of the timer in any way (the live is just for the clock on the timer). The photocell will output 230V when it goes dark and this live output is routed through the time clock contacts so if the timer is set to come on at 4PM and its 4.01 the lights will light, if its 3.59 they won't. Similarly if its 4.01 but still daylight outside then they wont come on until its dark, although the timer will be on.

  12. peter palmer

    peter palmer Well-Known Member

    If you wan't to override it then just fit a switch between the live and the lamp or the photocell output and the lamp if you still want it to go off when it gets light again.
  13. JP.

    JP. Screwfix Select

    Hmmmmm you can buy lamps with dawn to dusk sensors already built in - saves faffing with timers, and remote photocells and stuff..:)
    Last edited: Nov 15, 2018
    rogerk101 likes this.
  14. rogerk101

    rogerk101 Well-Known Member

    Agree completely ... it doesn't require any manual intervention and even takes care of the gloomier cloudy evenings when it's dark at 5pm as opposed to the following day where it's clear and bright at the same time of the day.
  15. Comlec

    Comlec Well-Known Member

    A timer can be useful if you don't want your lights on all night.
  16. peter palmer

    peter palmer Well-Known Member

    This is the set up I've got. Photocell wired via a 12V relay that is operated by my Premier 24 alarm panels output which is mapped to the built in timer function. It then goes to a switch by the front door that does the front light and at a switch by the patio doors that does some garden lights and some outdoor wall lights.

    Mostly I leave the garden lights switched on, they come on when its dark and go off at 11PM but only occasionally switch the wall lights on if I'm actually sat out there. The feed also goes to a 5A socket in the living room that a lamp is plugged into. The feed additionally goes to a socket on the landing that another lamp is plugged into but this feed is taken before the timer so its lit all through the night.

    This has worked flawlessly for about 5 years now which is surprising as I thought the panel or relay might have given up the ghost by now.

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