PIR affected by Fluorescent Light

[woodyray]

My mother has a 400w PIR floodlight on the outside rear of her bungalow. The cable is fed through a door frame (which is below the light) and it's plugged into a ring main socket in the room.

In the adjacent room there is an overhead single tube fluorescent light fitting, run off the lighting circuit.

Both lights have been in place for many years without any problems.

She recently noticed that when she turns on the fluorescent light, the outside PIR light also comes on. This only happens in the evening when it's dark outside.

I thought the fluorescent light was bit noisy when turned on so I replaced the starter. This made it a lot quieter but the problem still exists.

Can anyone please explain why the outside PIR light is coming on when the inside fluorescent light is turned on, and suggest a way to stop it happening?

Many thanks,

Ray

 

[ericmark]

For over a 150W lamp outside you need planning permission. So I would be looking to change it for a legal to use lamp. The fluorescent tube is coated on the inside with a material to change the frequency of the light emitted I seem to remember it would be ultra violet without the coating except for the ends which have an element to assist with starting. The element could trigger a PIR and the coating does seem to naturally leave the ends first. Likely a new fluorescent tube will help, also using HF ballast in the fitting often means the start element is not used so that could also help. Also the PIR could have a shield put in it so it does not see the fluorescent.

But before looking at the fluorescent I would look at the lamp and find out what is required to make it legal as if it needs replacing that may cure the problem anyway. Personally I would look at LED replacement tubes.

 

[SimonH2]

A friend has a similar issue - switching on a flouro tube in the bathroom triggers the outside security light. We both put it down to the outside light being "just a bit sensitive" to electrical noise, and the flouro creating spikes on the mains when starting.

 

[ericmark]

Before our dog died I was sent out every night to take it for a walk. Rather boring so I would take my handy with me and talk through miss piggy GB7MP while walking. Security lamps seemed to come on every time I pressed the PTT button. (Press to talk) I seems many are very poor for EMC and any RF and on they popped.

Car alarms were the same at one point they also failed to stop any RF entering the system. Today at least the car alarms have improved, also ABS brakes there was a point where some makes of car had it in their owners manual that not radio transmitter should be used in the car without an external aerial as it has been know for RF to upset the ABS. However my Vauxhall did not have ABS brakes but it was still in the manual do not use cell phones unless an outside aerial is connected to the phone.

But with a 5W LED lamp in my security lamp I could not care less if anything sets it off. As long as I can see from car to house it is doing its job.

 

[JohnD]

is that you, eric?

 

[stillp]

However my Vauxhall did not have ABS brakes but it was still in the manual do not use cell phones unless an outside aerial is connected to the phone.

That's because of the uncertainty about the effects of mobile phone radiation on human health. Putting the phone inside a steel container screens it from local cells, hence it will transmit at maximum power trying to communicate with a cell.

 

[ericmark]

However my Vauxhall did not have ABS brakes but it was still in the manual do not use cell phones unless an outside aerial is connected to the phone.

That's because of the uncertainty about the effects of mobile phone radiation on human health. Putting the phone inside a steel container screens it from local cells, hence it will transmit at maximum power trying to communicate with a cell.

I was always taught specially with the higher frequencies like 70 cm band to hold the radio at arms length. There were a few who used ear talkers so they could put the radio in a remote location like in their back pack, but that was unusually, most people do hold them to their head and only on the micro wave frequencies do we really worry.

However I have heard many times the polling hash produced by mobile phones it would seem their filtering is rather poor. I have also seen PLC with ASii malfunction due to mobile phones. Often we have really no idea of where the interference has come from, so banning mobile phones is the knee jerk reaction when you don't know. I have done it myself and latter it was proved it was caused by a mobile phone.

I have worked on sites using private mobile radios think we had around 500 and locating rouge sets and taking them out of service was my job. Often when found you could see physical damage to the aerial and where that was not the case often a dry joint on aerial connection. However the rouge radio still worked and the user was completely unaware that his radio was stopping another 10 radios working. We never get our phones tested and like any radio transmitter they can go rouge and upset other items near to them without the user being aware.

EMC is a duel edge but not transmitting on the wrong frequency and rejecting any transmissions which are around, however a simple rusty bolt can cause havoc as it acts as a diode. So where safety is involved simple method is to ban radio transmitters. The PMR or Ham radio is not so bad, we press the PTT and we see the reaction like a PIR lamp light. But with the mobile phone we have no control over the polling so when we see the odd event we have no idea our mobile has been the cause.

 

[ericmark]

is that you, eric?

Ups I had not noticed location. It may have been 1989 to 1995 but not in that area now.

 

[SimonH2]

[... locating rouge sets and taking them out of service was my job.

Did you have a dislike to red coloured radio sets ? At my last place they used the then new low power, licence free, business radio band - I recall the Motorola radios for that were red, and I could understand anyone taking a dislike to them (they weren't all that reliable).

 

[ericmark]

Darn spell checker again. Ones we used about 5 watt on the 70 cm band at least close enough that with new longer aerial I could use them. IC U16 I think they were called had 16 channels with link removed easy to program in new frequency and could use master to slave lead to program the IC U2 bought one latter thought I know how these work but changed now 32 channel and computer programmed it is on the ham band but I can't move it.

the Philips ones we had first were crystal controlled and did not use as much battery you could go all day on one battery but the Icom needed it changing at dinner time. Seem to remember we had about 60 frequencies for control to foreman yes the licence free would have done, but banks-man to crane-driver had to have a secure frequency. And even with 5 watt there were areas where out of range.

Seven bridge used a repeater and leaky feeder length of bridge that worked very well even inside the bridge.