Faulty low energy bulb or faulty electrics

[dx90]

I have a Philips low energy light bulb on my landing. From the very first day I put it in I have had a fault with it. If I put this bulb anywhere in the house it doesn't’t do it. If I put the same type and make of bulb from down stairs into the landing fitting that will do the same.
When the switch is turned off one of the three elements in the bulb will flash every 10 seconds then after a minute the other two elements will flash so it gets brighter. After some time the light will stop flashing until the next time it is switched on for any length of time then back off again.
The electrician has passed all lighting circuits when he did the part p. He said he doesn't know what is causing it.

What can be causing this?

Thanks

 

[breezer]

its quite common try a search for flashig cfl, its been mentioned before

 

[dx90]

I did a search and found some interesting facts on what is causing this.

Its says there should be a 3 wire and earth cable to go from down stairs switch to upstairs landing switch, 2 way 1 gange I think they call it. In my case its a twin and earth with the earth wire sleaved in red and used for the common. I pointed this out to the electrician. Is this a pass or fail being its old wiring?

Thanks

 

[breezer]

its dangerours the earth should never be used for a live

 

[dx90]

So it should never of been passed then?

 

[Taylortwocities]

It should not have been installed like that, did he install that?. When you say he did a part P, was he certifying work that he had done or reporting on work that had been done before?

You should have a document signed by him. What is the document called?

 

[dx90]

He has done work here but the lighting is old wiring that was already there. Part of his work here involved installing a CU so he had to check all of the electrics. Don't remember the certificate name but he is posting it soon.

 

[Taylortwocities]

If its done properly, you should get a Periodic Inspection Report that will detail any issues with your installation (including this issue with the wiring) and you should also get an Electrical installation Cert for the new work (new CU, etc).

Using twin & earth instead of three core and earth means:
1. there is a live conductor in the cable that should be double insulated. The earth conductor in a twin & earth cable does not have a sheath around it. that is not allowed in BS7671 (the regulations that govern electrical installations)
2. it means that there is no protective earth conductor in that cable (there should be) and also that there may not be an earth at the switch.

These deviations should be noted on the certificate and report that your electrician will provide. To properly resolve will mean removing the twin & earth and replacing it with 3-core and earth.

Now, will this cause the energy saving light to flash? It might do, but I have seen this problem on correctly wired installations. It is due to induced voltages somewhere. there are a couple of get arounds for this. one is to try a different maker of lamp as some are quite sensitive. have u tried another?

 

[dx90]

I understand about the dangers of having a earth wire as a live now.
I will see what is wrote on the certificate when it arrives.
The switch upstairs has an earth but not the one downstairs.
I have just exchanged the bulb with the one in the bedroom thats also a low energy bulb but made by Homebase and it hasn't flashed once. Its not as bright because it only has the two elements but its working fine.

Do you think this is caused by induced voltages somewhere?

How can it be found and fixed or is it just one of those things I will have to put up with?

Thanks

 

[Steve]

The light flickering is normal. We have a 20 watt 3 tube lamp that flickers when off, all the time, since it is on a 2 way switch circuit. What happens is the 3-wire switch drop builds up a charge on the dead 3rd wire which leads to the lamp. think of the cable as a capacitor.

The charge builds up on the live side of the lamp, and when so much has built up, the lamp discharges the charge across the tubes to neutral, causing a small flicker. So much charge must build up before there is enough energy to travel across the tube.

You dont see this with normal lamps because they have a filament, across which this charge can always flow at a steady rate.

The figures we're talking about are very small and there is no danger or ill effect caused by the phenomenon.

However, using the earth wire as a live conductor is dangerous. Get it sorted.

 

[securespark]

I would say not all sparks issue a PIR...

 

[Adam_151]

While its perfectly possible for this phenomenon to occur on a healthy circuit, faults such as floating earths, earths that arn't really earths (as in the OPs case) and switches in the neutral line can add to it

 

[dx90]

Just went through all the lighting in the house myself and everything is switched through the live correctly and all earthling from light to light is in place and correct apart from the earth in the downstairs switch to switch the upstairs light switch, that one is being used as a common for the switch. I will replaced with some 3 + earth soon, it’s been said that it’s very dangerous. Electrician said it has passed now that the reverse polarity on this light has been fixed.

I tested with mains power off with the continuity test on all earths from light to light. All seems to be ok.

What is a floating earth and how can I check for this myself?