Discuss Please check my logic for upgrade lights project wiring! in the UK Electrical Forum area at ElectriciansForums.net

renegade

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Hi all,

I have some outdoor lights, and I want to update the circuit to add a bit more functionality. I have drawn a little picture of what I have now:

Screenshot 2019-12-17 at 14.50.12.png

When we walk past the Outdoor PIR sensor 1, all lights come on, and then go off. This works fine!

Now the behaviour I want:

  1. Add another PIR sensor to the other side of the lights
  2. Add a dusk till dawn sensor (with timer)
  3. Add a manual override switch in the house(so from inside the house I can turn on all outdoors lights, and leave them on if i want).
I have drawn a diagram of how I think this could work - and would like some feedback on whether my logic is correct and will give me the behaviour I hope for:

Screenshot 2019-12-17 at 16.15.31.png


The Feed now goes to the junction box.
  1. Sensor 1 -- Switch and Neutral wired to SW and N of Junction
  2. Sensor 2 -- Switch and Neutral wired to SW and N of Junction
  3. Normal Switch -- Live is wired to common with S1 wired to SW of junction
  4. Dusk till dawn -- Live and N power timer (so i can control what time it should turn off at night time -- don't want it running till dawn, just 2am ish) -- this switch is wired to L of dusk till dawn. SW is wired to SW of junction box.
This should allow the following behaviours:

  1. Somebody can walk past PIR sensor 1 or sensor 2 and it will trigger all lights on
  2. Somebody can press normal override switch and all lights will stay on until the switch is closed
  3. Dusk till dawn is powered between hours that timer controls, and will trigger all lights on when timer is on and dark is detected.
Does this look ok? Any feedback? Thoughts appreciated.
 
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I think the logical thing is get a sparkie in. From what I can make out from that drawing there's a few fundamental mistakes that Dont make sense. Also you don't need the dawn to dusk sensor as the pir will have built in oned
 
Your diagram is not very clear quite confusing as a matter of fact, can you clarify?
Hi Pete999 - sorry - it wasn't very clear.

I tried colour coding the lines, and added a legend - hope that helps clear it up a bit?
[automerge]1576599465[/automerge]
I think the logical thing is get a sparkie in. From what I can make out from that drawing there's a few fundamental mistakes that Dont make sense. Also you don't need the dawn to dusk sensor as the pir will have built in oned
Actually I have had a sparkie in and he suggested I do it this way - hence i wanted to double check it! If you see some mistakes - please let me know. The PIR sensor does have one built in, but doesn't let me to the timer override, so i have to do it this way.
 
It's generally OK and will give each of the behaviours you want. There is a slight minor objection that the output of the dusk-dawn sensor may be back-fed from the main SL terminal if either PIR or the override are active while its input (the timer output) is off. Whether this will cause any problem with the sensor will depend on its design; it shouldn't do and won't affect the operation of the lights anyhow. The lights may come on briefly when the timer goes live, even if it's not dark, while the sensor wakes up.

StephenRowley I believe the idea of the separate dusk-dawn sensor is to bring the lights on independently of the PIRs when it gets dark, then they go off at the predetermined time, leaving the PIRs active to bring them back on if anyone approaches after that. The sensor is not intended to control the PIRs, they rely on their own sensors to not trigger the lights during the day.

Seeing as I've given you the most accurate review of your proposal, I hope you won't mind me going further than Pete and saying that is about the worst drawing of anything I've seen for a long time :) The right things are connected together but I might need a beer to recover from the assault on my aesthetic sense.
 
It's generally OK and will give each of the behaviours you want. There is a slight minor objection that the output of the dusk-dawn sensor may be back-fed from the main SL terminal if either PIR or the override are active while its input (the timer output) is off. Whether this will cause any problem with the sensor will depend on its design; it shouldn't do and won't affect the operation of the lights anyhow. The lights may come on briefly when the timer goes live, even if it's not dark, while the sensor wakes up.

StephenRowley I believe the idea of the separate dusk-dawn sensor is to bring the lights on independently of the PIRs when it gets dark, then they go off at the predetermined time, leaving the PIRs active to bring them back on if anyone approaches after that. The sensor is not intended to control the PIRs, they rely on their own sensors to not trigger the lights during the day.

Seeing as I've given you the most accurate review of your proposal, I hope you won't mind me going further than Pete and saying that is about the worst drawing of anything I've seen for a long time :) The right things are connected together but I might need a beer to recover from the assault on my aesthetic sense.
LOL Lucien!

First off - thank you for your explanations.

Secondly -- can you take 5 minutes, to redraw it for me - that way I can learn how to draw it better next time!

Thirdly RE the backfed to dusk till dawn -- isn't that also the case with the 2 PIR sensors and the manual switch?
 
As long as none of the lives, or switched lives connect to a neutral, (or earth) it should pass the bang test.
After that, it’s just seeing if it works the way you want it to.
 
RE the backfed to dusk till dawn -- isn't that also the case with the 2 PIR sensors and the manual switch?

They are backfed, but as their inputs are always live, this is a normal situation, their own electronics remain powered by the input. What is abnormal about the sensor is that it can be backfed when the input is dead (due to the timer being off), so if it is active when the timer goes off, the electronics start being powered from the output instead of the input.

If the sensor output is switched by a relay, there won't be any problem; it simply won't notice that the supply for its own electronics is coming in via the output as the relay makes a solid connection. It will go off and stay off once the source of the backfeed itself goes off, and no-one will be any the wiser. If its output is switched by a triac, then it might perhaps object to as the load won't be sufficient to hold the triac on properly, possibly making it go wobbly or cycle on and off while it shuts down. Unlikely though, and probably harmless.

Had the timer been controlling anything else independently, then the backfeed could cause a mis-operation, as it would bypass the timer if both controlled devices were active at once.
 
They are backfed, but as their inputs are always live, this is a normal situation, their own electronics remain powered by the input. What is abnormal about the sensor is that it can be backfed when the input is dead (due to the timer being off), so if it is active when the timer goes off, the electronics start being powered from the output instead of the input.

If the sensor output is switched by a relay, there won't be any problem; it simply won't notice that the supply for its own electronics is coming in via the output as the relay makes a solid connection. It will go off and stay off once the source of the backfeed itself goes off, and no-one will be any the wiser. If its output is switched by a triac, then it might perhaps object to as the load won't be sufficient to hold the triac on properly, possibly making it go wobbly or cycle on and off while it shuts down. Unlikely though, and probably harmless.

Had the timer been controlling anything else independently, then the backfeed could cause a mis-operation, as it would bypass the timer if both controlled devices were active at once.
Got it -- what could be done to work around that issue in this case (I know it is probably overkill, but am interested in options regardless)
 
sorry - it wasn't very clear.

The diagram was looking good until you added a house

Send us a picture of the junction box when it is done
It will look just like his diagram, with less straight lines ;)

What is abnormal about the sensor is that it can be backfed when the input is dead (due to the timer being off)

It shouldn't be backfeeding the sensor, it only backfeeds the switch part of the circuit
 
You might want to go through the logic of a timer switch before a dawn-dusk switch; the timer seems superfluous to me.

To avoid running cables to PIR sensors and override switch you could use these wirelessly connected devices to a receiver switch:

EasySwitch Easy Switch Wireless Switches - https://www.tlc-direct.co.uk/Main_Index/Pumps_and_Aquatics_Index/EasySwitch/index.html#EasySwitch

The use of the wireless receiver switch would allow the use of fobs which folk could carry or be left in the car and could obviate the need for the override switch. If you still wanted a separate override switch there is fixed wireless switch which would suit.

Are you bothered about animals or on windy nights swaying trees setting off the PIR for the lighting - it could become annoying.

You might want to think also about beam cutting or retro reflective sensor switches eg:

Takex PR-11B 15m Reflector Beam Sensor - https://connectec.uk/security/intruder-alarms/perimeter-detection/takex-pr-11b-15m-reflector-beam-sensor?gclid=Cj0KCQiAuefvBRDXARIsAFEOQ9GDzyPYfHUOqPWb_5qbAd42I19Gnw5kjYKs1ci9rJVFhd55uzDUvBQaAs_rEALw_wcB
 
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