Pir Operated Led Floodlight Fittings.

[southsparks]

Two months ago I was asked to fit some (supplied) LED light fittings to a building frontage, three are PIR type, and two without. Just recently

the three PIR type have started flashing on & off every time they are triggered. The other two are working OK. It just happens this

circuit is photo-cell operated, so the PIR fittings are turned on & off every day. I realise that PIR fittings should be fed from a permanent

supply, but I thought it would be OK to use the PIR ones on that circuit. I have done all the usual checks to fittings supply, and tried by-passing

PIRs, to no avail. It looks like the drivers are now at fault. I have taken them down & hope to be asked to fit non-PIR type, to simplify the

set-up, to all on dusk to dawn. I think otherwise, I would have to run a separate circuit for any new PIR type fittings, and leave the others

on the photo-cell. Would this regular switching off & on every day be the cause of the fittings drivers to fail? The instruction say the lamps can

be turned on & off  up to 15,000 times. They are LAP make & 50watt.  I wasn't too keen on mixing the two types of fitting on the same circuit

but thought it wouldn't matter if the three PIR fittings went through their switch-on test mode each day. Looks like I was right to be concerned

about the possibility of a problem developing. I can mention that I tested all the fittings back in my work-shop and they still all strobe.

Has anyone else come across this problem? thanks for any help or advice you may have.

Southsparks.

 

[ProDave]

Since it was customer supplied units that have failed, I hope you are charging labour to sort it out. It is NOT a warranty issue on your part so you should not be out of pocket.

 

[southsparks]

Thanks for reply Dave. Not actually worried about being  of pocket, just if I had done something wrong. It does sound like a common fault 

I agree. Have had several cases of newish LED fittings fail, due I believe to some sort of mains surge, in the past. Not too sure I can trust

these LED lights, as they do seem to be bit of a problem, unlike good old fluorescents.

Southsparks.

 

[kerching]

Do you mean all fittings are on a switched circuit ( switched by P CELL..?)

Quite often PIR fittings go,through an initial,set up procedure when power is first applied....is this is what is happening ?

If the wiring is at fault,it is your problem as they have been wired incorrectly with no,permanent feed

If the fittings are faulty. Then it is your customers problem

If it can be proved that the constant switching of the supply by the P,cell,has caused the fittings to fail then it will,most likely be your problem

The lamps MAY be capable of being switched 15000 times.....NOT the mains supply to the PIRs

Especially,with LAP fittings!

Just saying

 

[Doc Hudson]

Without seeing the specific installation instructions I would be inclined to agree with Kerching that the 15,000 refers to the minimum expected number of switching cycles that the PIR is designed to do. Not the lamp itself. I would have thought the lamp should be no different from a non-PIR operated lamp and designed to be turned off and on just as a normal lamp may be turned off on numerous times in a day. If all three have failed within a similar timespan then the non permanent supply could be a contributing issue. How long are the cable runs and what rating are the lamps, what is the total load on the circuit?

Doc H.

 

[southsparks]

Thanks for all the replies. Yes all the five fittings, three PIR type & two "straight", total wattage 250, wired on quite a long run in 1.5mm cable in

a daisy-chain way, and fittings have been installed about two months. Circuit originally had five X 70 Watt sodiums on it, wired by me 20 years ago.

No problem with cables, as I have checked all junction boxes etc. Circuit been in operation 20 years without any problem. Nothing to do with

new photo-cell or its wiring, as the "straight" fittings come on and stay on with no indication of strobing. (Old sodiums had integral photo-cells).

I did ask for all new LED fittings to have integral photo-cells,(dusk to dawn) but not available apparently. Would have saved me from installing new photo-cell.

I pretty sure now that the daily switching to the PIR fittings has somehow messed-up the operation, but although I can see  that might affect the PIR unit,

how could the drivers be so affected? they are quite separate parts of the fittings. Obviously the 15K hours refers to the actual switching of the LED lamp.

Guess I should not have mixed & matched the two different fitting types, and insisted on either all PIR type or all straight ones, on P-cell operation.

Despite what I have said, still can't see why daily dusk switching on and running through test-mode should affect the drivers, and why they should all go

almost at same time and display the same symptons. If all of the fittings were the same type, (straight) presumably this problem should not re-occur.

Don't really fancy having to wire another separate circuit just for the PIR type if the customer insists keeping  some PIRs, for energy-saving reasons.

Southsparks.

 

[southsparks]

Just one thing I forgot to mention, perhaps PIR detectors need a constant power supply, like LNB satellite dish signal collectors, as they too generate a 

small amount of heat to prevent build-up of moisture, that can cause failure of the electronics, which is why you should always leave your Sky-box

powered and not turned-off. Just something I found on the Net after my mothers Sky-dish failed, when she started turning it off at the plug,

despite us telling her not to.

Southsparks.

 

[kerching]

Never yet seen a PIr that did NOT need a permanent supply

 

[ProDave]

A sky box is left on so it can record and get over the air software updates, not to warm up the LNB.

 

[Lurch]

A sky box is left on so it can record and get over the air software updates, not to warm up the LNB.

Although the warming up of the LNB is a positive side effect of leaving the box on for the OTA updates.

 

[southsparks]

Thanks for further replies. Just looking at fittings leaflet, and it warns against "storing fitting in a very cold or hot/damp place"

as this can damage the electronics. Just wondering how this applies to when fitting installed outdoors, as those conditions

will happen throughout the year. Perhaps when powered-up, this doesn't apply, so for that reason switching on & off each 

day could lead to premature failure of driver?. Seems that advice about LNB devices a bit of an old wives tale. That's the Net for you!

Have found the 15K switching on/off also applies to non PIR fittings, so they must be referring to driver/LED lamp in that case.

That works out at 365 dusk switch-ons per year, or 41? years for the full 15K times. Might shorten its life-span a bit I suppose.

Think the main reason to leave PIR powered up all the time, is so they will be ready for action when night falls,but if turned off

deliberately, might not get turned on for the next night. Or it may affect the PIR in some way, but unable to see how it could take

all LED drivers out. In this case the PIRs are still operating properly,also I tried by-passing them, to no avail. Perhaps a power-surge 

in supply? that I know from experience can wipe-out LED drivers. So far no other LED fittings in building affected. Not known if any other

electrician has gone into building and done a routine 500 volt Megger test of the buildings electrics.. You never know. 

Southsparks.

 

[Lurch]

I tried by-passing them, to no avail.

Switching them on and off from the photocell would not have affected this then as the driver would only be on when the PIR is on anyway.

Crap drivers, problem solved.

 

[Blue Duck]

Thanks for further replies. Just looking at fittings leaflet, and it warns against "storing fitting in a very cold or hot/damp place"

as this can damage the electronics. Just wondering how this applies to when fitting installed outdoors, as those conditions

will happen throughout the year. Perhaps when powered-up, this doesn't apply, so for that reason switching on & off each

day could lead to premature failure of driver?. Seems that advice about LNB devices a bit of an old wives tale. That's the Net for you!

Have found the 15K switching on/off also applies to non PIR fittings, so they must be referring to driver/LED lamp in that case.

That works out at 365 dusk switch-ons per year, or 41? years for the full 15K times. Might shorten its life-span a bit I suppose.

Think the main reason to leave PIR powered up all the time, is so they will be ready for action when night falls,but if turned off

deliberately, might not get turned on for the next night. Or it may affect the PIR in some way, but unable to see how it could take

all LED drivers out. In this case the PIRs are still operating properly,also I tried by-passing them, to no avail. Perhaps a power-surge

in supply? that I know from experience can wipe-out LED drivers. So far no other LED fittings in building affected. Not known if any other

electrician has gone into building and done a routine 500 volt Megger test of the buildings electrics.. You never know.

Southsparks.

I can't read this any more.

Sorry but the double returns are sending me bonkers!

 

[southsparks]

Thanks Lurch. Sounds like you are spot-on. Time to close this subject. I do get carried away a bit. "Brevity is to be encouraged"

Southsparks. 

 

[binky]

damp in PIR would be my main suspicion, I've given up fitting combined units as they all seem to leak at the elbow join and ****** the PIRs. Other than that, cheapo fittings as per Lurchs' comment.

 

[southsparks]

Just quick up-date, seems other installers have had exactly the same problem, failure and strobing after two months. (Screwfix's Site) Looks like its

the drivers giving up, not the PIR or how I wired them. 

Thanks.

Southsparks.

 

[Lurch]

I've just had an Eterna 11W with PIR stop working as well, looks like a driver issue. Only a few months old.

I've fitted a few things recently with ropey looking drivers, it is quite difficult to find anything that isn't total **** tbh.