LED’s bought from another retailer have failed with blackened area between the two terminals, help!

Customer Questions 

I bought some LED Spots from another online retailer and had some issues with them and their laughable ‘technical support’, so I hope you don’t mind me contacting you as I’m worried by something. One LED failed quickly another a few more after 10 months. All the failure had a greatly blackened area around and between the two terminals – see attached photo.  It had also blackened the light fitting in the same area also. The photo may give you some idea about the reason for failure.  I’ve no idea who made that failed bulb as the box contained no name and on the barrel of the bulb it says 6W 230V AC DIM and underneath that it says GU10 CE ROHS.  Presumably the DIM indicates that it’s dimmable.


Technical Tim


We need you to immediately stop using the bathroom lights.

Turn off the power at the fuse box by either removing the fuse or the breaker or if not sure turn ALL the household power off.

Having made sure that the power is isolated, examine ALL the lamps and fittings in the bathroom and look for similar blackening.

If there is any blackening on the fittings use WD40 and an old toothbrush and remove the blackening. If it is not possible to remove it then I would advise that the base is replaced. Any lamps that show blackening should be replaced and not cleaned.

If unsure of procedure utilize the services of a qualified electrician.

The blackening is caused by electrical discharge between the two metal parts of the lamp causing carbonization of the surface and if permitted to build up will provide a more conductive circuit path which will permit more current to flow leading to an increase in current, heat and the potential of fire due to the flow of power.

I have no idea why this has happened from the photograph provided but it is an immediate source for concern especially considering the units are in the bathroom and there is a void, or should be above them. If the carbonization continues, the lamp holder will become hot, the carbon will smoulder and will continue to smoulder even if the power is removed.

IF the blackening cannot be removed electricity will continue to leak across the blackening leading to a breakdown and potential fire and the part MUST be replaced. Take no chances.


Further thoughts on the subject.

It is likely that the issue has possibly been caused by poor contact between the pins on the lams and the spring contacts on the holder although this is not apparent from the small photograph. It is possible that the lamp has not been fully twisted to locate the lamp correctly in the holder causing poof contact and electrical arcing resulting in the deposits observed.

It is essential that the holder is examined for any signs of deterioration of the metal contacts such as pitting/burning/corrosion; if in doubt the holder should be replaced, the cost is minimal and the possible consequences are frightening to consider.


I do appreciate your consideration and help.  You could be right about the lamp not being fully engaged as the bulb holders have only about a millimetre or two of clearance from the width of the bulb and as they are fully recessed it makes it difficult to use the fingers to apply enough turning force.  The same applies of course with removal, which is one of the attractions of long life!  The old Halogen ones had a smooth glass  front that enabled use of a suction pad, but the LED ones won’t accept that method of assistance.

I am making urgent contact with a competent electrician to get things checked through.

I have had a “rated people” electrician carry out a full examination of my bathroom lighting system with the conclusion that all’s well and no work needed . He said that the cowlings were good fireproof ceramics and very safe. He also checked in the loft under the insulation to make sure evidence of excessive heat wasn’t present.

One strange thing though – the lamp that failed and was supplied  by my local electrician was difficult to remove from the fitting as instead of disengaging the pins when applying anti-clockwise motion the glass element of the lamp revolved, unscrewing and leaving the ceramic base plugged in.  I had to press upwards hard and then revolve to achieve disengagement.  That was another bad mark against the failed bulb!


That’s good to hear you have it sorted, you can never be too careful with electrics.

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