Dusk till 11pm timer

[mfarrow]

Why would a 'dusk till dawn' operation require any timer?

As John explains I was referring to the term being widely used in my experience to describe a timer device which adjusts to the calendar parameter set and cannot sense light. I believe that's what the OP was referring to.

Technically speaking you cannot have dusk to dawn operation in a timer alone as those very definitions imply a reduced amount of light which those timers cannot sense. It's different to sunrise/sunset That does not stop people selling and buying them though!

 

[JBR]

Keep it simple. I recently installed one of these:

http://www.amazon.co.uk/gp/product/B0018S13PO?psc=1&redirect=true&ref_=oh_aui_detailpage_o03_s00

Inexpensive - about £20 - and easy to set up. It does not include a light sensor, but I just re-set the time once a week or so to account for the change in dusk and dawn times. Easy and quick to do.

 

[333rocky333]

Merlin gerin do a din rail mounted digital timer with built in photocell control, the light sensor is connected using 2 core cable, the lux setting is also adjustable on the unit and has 90 second delay to compensate for overcast and car headlights
though there not cheap

 

[333rocky333]

Only hiccough though is when the clock comes on in the afternoon, and puts supply to PEC, the PEC is closed to begin with, and the light comes on briefly until the cell recognises that it's daylight and switches off.

Why not go through the photocell before the timer contacts

 

[JohnW2]

Only hiccough though is when the clock comes on in the afternoon, and puts supply to PEC, the PEC is closed to begin with, and the light comes on briefly until the cell recognises that it's daylight and switches off.

Why not go through the photocell before the timer contacts

One obviously can do that but it means that the photocell is powered 24/7 - which, particularly in the case of the 'thermal' (as opposed to 'electronic') ones, can appreciably reduce their life. [In my case, the timer is also doing 'other things', which is another reason why I have it before the photocell !]

Kind Regards, John

 

[JohnW2]

Keep it simple. I recently installed one of these: ... Inexpensive - about £20 - and easy to set up. It does not include a light sensor, but I just re-set the time once a week or so to account for the change in dusk and dawn times. Easy and quick to do.

I would never remember to do the resetting! A timer and a photocell need not cost much more than £20- so is the 'lazy' approach I've taken!

Kind Regards, John

 

[DIYTom]

Why would a 'dusk till dawn' operation require any timer?

As John explains I was referring to the term being widely used in my experience to describe a timer device which adjusts to the calendar parameter set and cannot sense light. I believe that's what the OP was referring to.

Technically speaking you cannot have dusk to dawn operation in a timer alone as those very definitions imply a reduced amount of light which those timers cannot sense. It's different to sunrise/sunset That does not stop people selling and buying them though!

In my original question I was thinking about the photocell systems. I didn't know you could get a mechanical version.

Thanks all for your help. I'm going to go for the 'lazy' way and have a timer in series with a photocell. Bit more wiring but a much easier option.

 

[DIYTom]

One more question. Does anyone know of a dusk till dawn sensor with a remote photocell (preferably wired). It would make the wiring easier if the box that does the switching could be in the garage next to the timer switch.

 

[JohnW2]

One more question. Does anyone know of a dusk till dawn sensor with a remote photocell (preferably wired). It would make the wiring easier if the box that does the switching could be in the garage next to the timer switch.

I imagine that such things probably exist, although I can't point you to one. However, since you would have to run a cable of some sort to the 'remote photocell' (unless it were wireless), I don't really see why it makes any difference whether the actual switching happens at the photocell or in an extra box in the garage, does it?

Kind Regards, John

 

[DIYTom]

i want to power a light under the eaves of my garage, with the cable drilled through from inside, and then four posts down the drive from an armoured cable. it would save an outside join (an therefore weak point) if the dusk till dawn sensor could be inside. I am assuming the photocell for that would be 12 or 24v and could again be drilled through from the inside.

 

[JohnW2]

i want to power a light under the eaves of my garage, with the cable drilled through from inside, and then four posts down the drive from an armoured cable. it would save an outside join (an therefore weak point) if the dusk till dawn sensor could be inside. I am assuming the photocell for that would be 12 or 24v and could again be drilled through from the inside.

I'm not exactly sure what you mean by 'the dusk to sawn sensor could be inside'. There is very little to one of these devices other than the photocell itself, and there are plenty designed to be outdoors. The ones I use have been outdoors, fully exposed to the elements, for about 30 years, and usually last a good few years (probably best part of 10 years) before needing to be replaced. There is no 'join' outdoors, other than the connection of the cable to the photocell/switch.

Kind Regards, John

 

[DIYTom]

i want to power a light under the eaves of my garage, with the cable drilled through from inside, and then four posts down the drive from an armoured cable. it would save an outside join (an therefore weak point) if the dusk till dawn sensor could be inside. I am assuming the photocell for that would be 12 or 24v and could again be drilled through from the inside.

I'm not exactly sure what you mean by 'the dusk to sawn sensor could be inside'. There is very little to one of these devices other than the photocell itself, and there are plenty designed to be outdoors. The ones I use have been outdoors, fully exposed to the elements, for about 30 years, and usually last a good few years (probably best part of 10 years) before needing to be replaced. There is no 'join' outdoors, other than the connection of the cable to the photocell/switch.

Kind Regards, John

I'm not explaining myself very well. The photocell unit itself must have a photocell, a few electronic bits and bobs to set sensitivity, and wether it's dusk thill dawn or dusk plus n hours, and then a relay to switch the 240v. What I was thinking is all of that bar the actual photocell could be inside, with the actual photocell outside. That would just be one component and a 12v lead (presumably).

I guess it can't be done though so never mind. I'll just have to put an extra junction box outside to run the cables back inside for the garage light and the other one on down the drive.

 

[JohnW2]

I'm not explaining myself very well. The photocell unit itself must have a photocell, a few electronic bits and bobs to set sensitivity, and wether it's dusk thill dawn or dusk plus n hours, and then a relay to switch the 240v. What I was thinking is all of that bar the actual photocell could be inside, with the actual photocell outside. That would just be one component and a 12v lead (presumably).

I think we're talking somewhat at cross-purposes. I'm talking about essentially 'dumb' photocell-switches (which, as I said, contain very little - particularly the 'thermal', as opposed to 'elecronic' ones), which cannot do clever things like "dawn or dusk plus n hours". The ones I use are like this (widely available):

(click here for details)

I guess it can't be done though so never mind. I'll just have to put an extra junction box outside to run the cables back inside for the garage light and the other one on down the drive.

I still don't really understand why you would need an 'outside junction box'. The wires from the photocell-switch and the light on the garage can go straight through the garage wall into the inside of the garage and then be run to the vicinity of time switch, and all the 'joining' can be done there (with a JB if necessary) ... or am I missing something?

Kind Regards, John

 

[333rocky333]

Merlin gerin do a din rail mounted digital timer with built in photocell control, the light sensor is connected using 2 core cable, the lux setting is also adjustable on the unit and has 90 second delay to compensate for overcast and car headlights
though there not cheap

Also the same thing without a timer
i would use a din mounted contacter too, rather than having all the load via the p/c timer set up

 

[JohnW2]

i would use a din mounted contacter too, rather than having all the load via the p/c timer set up

I suppose there's a theoretical argument for that, but I've had no real problem (in ~30 years) with all the load going through the photocell + timer - using a standard 16A 'immersion heater' timeswitch and a photocell as illustrated in my last post - and for a good few of the early years, the load was quite substantial (three PAR38 floods, for a start) - 'a few hundred watts'. Both timers and photocells have usually lasted for best part of a decade.

Kind Regards, John