Carpark lighting

[Steviegee]

Hi guys,I’m a maintenance electrician for the council but unfortunately control circuits aren’t my forte,anyway would anyone know the wiring setup for contactor,time clock,photocell,and a hand/off/auto switch for car park lighting. Sorry can’t get my head around it so a wiring diagram or link would be perfect. Thanks..

 

[MJPD29]

Have you got a pic of the setup? Might help for drawing some lines or descriptions on. Or is this a new installation to be done

 

[Steviegee]

Have you got a pic of the setup? Might help for drawing some lines or descriptions on. Or is this a new installation to be done

Hi Matthew,here’s the set up of another carpark I worked at years ago,pity I didn’t take a picture of the wiring behind it. Was trying to get a replacement time clock to be honest. The carpark lighting I’m going to be doing is identical to this,just need the wiring diagram for it all...

 

[davesparks]

It depends how you want the controls to work.

Do you need the timeswitch and photocell in series or in parallel?
What should the three position switch do in each position? Presumably auto would allow control via the timeswitch and photocell, off being completely off and manual being an override on?

 

[Steviegee]

It depends how you want the controls to work.

Do you need the timeswitch and photocell in series or in parallel?
What should the three position switch do in each position? Presumably auto would allow control via the timeswitch and photocell, off being completely off and manual being an override on?

That’s exactly right,regarding the setup of the controls,I take it that’s in parallel?..

 

[davesparks]

That’s exactly right,regarding the setup of the controls,I take it that’s in parallel?..

What I described is a possible operation of the three position switch.

I asked whether the photocell and timeswitch were to be in parallel or series. How are they intended to operate?

 

[Steviegee]

What I described is a possible operation of the three position switch.

I asked whether the photocell and timeswitch were to be in parallel or series. How are they intended to operate?

The time switch will be overriding the photocell (lcarpark lights off at a certain time), so running in parallel with each other.. could you explain the running in parallel concept and series concept as well. As I’ve said I’m not great at control circuits,thanks again.

 

[Phil Thompson]

I would imagine in series, with timeclock being used to control operation at a closed period during the night, but the photocell controlling the rest of the dark period which will vary depending on length of daylight.

 

[davesparks]

The time switch will be overriding the photocell (lcarpark lights off at a certain time), so running in parallel with each other.. could you explain the running in parallel concept and series concept as well. As I’ve said I’m not great at control circuits,thanks again.

That wouldn't be the two controls in parallel, that would be series. The override switch would be in parallel with the other controls.

Series and parallel are not specific to control circuits, these terms are used at the most basic level of electrical circuits.

Does the timeswitch being used have a volt free/relay output?
Most of them do, whereas a lot of photocells do not, so it is usually easier to take the switched output from the photocell then control that with the timeswitch if the desired method of operation allows this. Otherwise you may need to add other components.

Have you considered a timeswitch with built in dusk/dawm switching? The Sangamo suntrackers are very good for this and can have an early off option.

 

[Steviegee]

I would imagine in series, with timeclock being used to control operation at a closed period during the night, but the photocell controlling the rest of the dark period which will vary depending on length of daylight.

Yes that’s correct,would you have a link or wiring diagram of that particular set up?...need it for Monday if possible

 

[Phil Thompson]

I don't have anything to hand but it would be

Supply >>> timeclock >>> photocell >>> light, or contactor

 

[davesparks]

I don't have anything to hand but it would be

Supply >>> timeclock >>> photocell >>> light, or contactor

As I said earlier, and depending on the exact details of the components it is often better to have the photocell first.
Most photocells are 3 wire (L N and S/L) whereas timeswitches usually have a relay output. So the timeswitch can switch the output of the photocell, but the other way around the timeswitch will be cutting the feed to the photocell. This may, or may not, be a problem depending on the photocell, some of them will come on for a few seconds then go off for a period before operating as normal each time the feed is energised.

 

[Phil Thompson]

I have heard this being an issue before from older sparks mentioning it, but have never experienced it myself, and even using the override feature thus energising the photocell the lights have turned on and stayed on with no on off issues.