Light Bulb fuses house? Help required?!?

[Marc138]

I have a standard bedroom light (have replaced bulb several times with energy efficient bulbs)

Every time I replace the bulb within a few days (sometime hours) the bulb will blow and it will blow the fuse wire for the lights (old fuse box) in the whole flat. I therefore need to replace the fuse wire in the fuse box......and process starts all over again

Any ideas? I haven't touched the actual light switch....would this make a difference to replace it?

 

[amjmfareham]

Hi Marc138,

Welcome to DIYNot.

The light bulb blowing could indicate that there is a breakdown with the circuit (including: Cables and/or Wiring Accessories that are connected to the circuit), as indicated by replacing the fuse wire in the fuse holder on a regular occurrence, furthermore, I would expect that the expertise of a Qualified Electrician is needed to address this fault.

In the meantime, one of the forum electricians will be on here soon to give more assistance to this thread, as I don't want you to get hurt!

Hope this helps!

Andrew

 

[bubachuba]

could be a loose connection which will draw more current than intended. if you are competent, isolate the supply (pull the fuse carrier) and check the circuit is dead and then check all the connections inside the light fitting and switch are ok

 

[ban-all-sheds]

The light bulb blowing could indicate that there is a breakdown with the circuit

What do you mean by that?

 

[ban-all-sheds]

could be a loose connection which will draw more current than intended.

How does a loose connection do that?

 

[ban-all-sheds]

I have a standard bedroom light (have replaced bulb several times with energy efficient bulbs)

Every time I replace the bulb within a few days (sometime hours) the bulb will blow

Does the same problem happen with ordinary light bulbs?

What type of replacement bulbs are you buying? What voltage do they say they are for?

Where do they come from and where are you buying them?

I haven't touched the actual light switch....would this make a difference to replace it?

No.

 

[amjmfareham]

The light bulb blowing could indicate that there is a breakdown with the circuit

What do you mean by that?

Hi BAS,

What I mean by that is such faults, including Line-to-Earth faults on a perished rubber-sheathed cable, or a loose connection at connection points, for example.

I took what was described at face value, as there is no photos to indicate otherwise!

Also, I suggested seeking the advice of a Qualified Electrician because we are not there and we would not know what the condition of the set-up is like from the other side of the computer screen!

Kind Regards,
Andrew

 

[ban-all-sheds]

What I mean by that is such faults, including Line-to-Earth faults on a perished rubber-sheathed cable, or a loose connection at connection points, for example.

How could either of those cause light bulbs to blow?

 

[amjmfareham]

What I mean by that is such faults, including Line-to-Earth faults on a perished rubber-sheathed cable, or a loose connection at connection points, for example.

How could either of those cause light bulbs to blow?

It could be a possibility, we don't know what the extent of the situation is because we are not there!

Also, my first post got a "Thanks" from the Original Poster by the way!

 

[bubachuba]

could be a loose connection which will draw more current than intended.

How does a loose connection do that?

On the basis that a loose connection/high resistance results in voltage drop. lower voltage means the load will draw more current.

 

[stillp]

could be a loose connection which will draw more current than intended.

How does a loose connection do that?

On the basis that a loose connection/high resistance results in voltage drop. lower voltage means the load will draw more current.

No it doesn't! Remember Ohm's Law?

 

[EFLImpudence]

If it were the case 0V would mean infinite current - but it doesn't.

 

[bubachuba]

i stand corrected! i am sure (it was a while ago!) that we did an experiment in college where the motor was pulling more current when we simulated a less than perfect connection but will bow down to the knowledge of the forum

 

[EFLImpudence]

That may be the motor struggling with insufficient voltage.

 

[ericmark]

A bad or intermittent connection can cause through repeated starts the compact fluorescent to have a reduced life, with PWM LED lamps it could affect the regulator chip however in neither case would that explain why the fuse ruptured. In theroy every bulb should have a built in fuse or at least those with BA22d fittings as in the main the bulb holder only rated at 2A and fuse rated at 5A but I know from bitter experience this is not always the case.

So I would first look at the bulb. I know I had a problem with bulbs from Ikea it would be nice to say don't use cheap bulbs but again experience has shown expensive can be as bad as cheap. So I would swap supplier to start with and see if there is an improvement. Even if the bulb fails prematurely because of a bad connection it should not cause them to go short circuit. If it is a bad connection causing bulbs to fail I would think the LED type would be less susceptible to damage although can't be 100% sure on this, but I would consider trying an LED bulb.

If you can find a tungsten bulb to fit the holder this may help identify the fault. The extra load would likely cause a bad connection to get a lot worse but not sure if this would be good or bad as bad connections can cause fire under heavy load. Problem is we don't really know if bulb failure is due to bad connection or simply poor quality bulbs.

i stand corrected! i am sure (it was a while ago!) that we did an experiment in college where the motor was pulling more current when we simulated a less than perfect connection but will bow down to the knowledge of the forum

A motor can draw more current when it has under voltage or loses a phase. The same could be true with pulse width modulated or switch mode power supplies as they compensate for the volt drop so yes a LED bulb say 5W would draw 22 mA at 230 volt but 33 mA at 150 volt. Under 150 volt it will likely simply fail to run and even if you had a 50W LED lamp it would still only draw 330 mA at 150 volt which would not rupture a fuse.

So in real terms bad connections should not cause enough extra current to flow to cause the situation described. With a standard wire wound ballast on a fluorescent again it would not cause any extra current to flow. But with a HF ballast then the spikes in the voltage due to a bad connection could cause electronic components to fail. So it is possible spikes due to bad connection could cause diodes in the HF ballast to fail which could fail short circuit. I personally think it is unlikely but will accept it is possible. In the main I think the CFL uses an electronic ballast so could be affected by spikes.

I find a standard radio is a good tool for finding if there is a bad connection as spark transmitters will cause interference better to use Medium Wave if you get interference when lights are switched on then either bulb or wiring is faulty.