Electrical Advice Please

[KneesUp]

At work we have a light from Ikea which I would show as an image if they still did them, but basically it's two wires strung across the ceiling connected to a power supply you mount on a wall, and then that plugs into a normal socket. There are five light fittings that you screw into the wires - if you went to Ikea between about 1995 and 2015 you will have seen them.

Anyway - there is one at work that's been up for - er - maybe 10 years - and today it won't work. If I remove a couple of bulbs, it briefly manages to light up two of the three remaining bulbs, but then they go off.

It has had a mixture of 2 LED bulbs and 3 halogen bulbs for a few years. It wasn't fully LED because it doesn't seem to have the power to get 5 LED ones to start up. The ones I've removed are the LED ones.

Any thoughts as to what might be the problem? It's going to be a sod to replace it because of where it is, so any tips much appreciated.

 

[fossyant]

Correctly rated wattage on the bulbs. We have a lamp that will only work with 5w capsule bulbs. Any more it won't work

The transformer could be knackered

 

[swee'pea99]

it briefly manages to light up two of the three remaining bulbs, but then they go off.

'two of the three', for me at least, would point the finger of suspicion at the third. Can you try swapping that for a new bulb, and putting all the others back? That's what I'd do for starters.

 

[Yellow Saddle]

I'll take a stab. The transformer's rectifier has blown. LED bulbs can only work on DC whereas halogen can do DC and AC. The transformer used to pump out DC, but now it pumps out AC.

 

[KneesUp]

Correctly rated wattage on the bulbs. We have a lamp that will only work with 5w capsule bulbs. Any more it won't work

The transformer could be knackered

MY thought was the transformer - but @swee'pea99 is correct - hasn't occurred to me for some reason that the remaining bulb that doesn't work might be the issue. Also possible that with only 3 bulbs in the resistance is too low, or something?

 

[KneesUp]

I'll take a stab. The transformer's rectifier has blown. LED bulbs can only work on DC whereas halogen can do DC and AC. The transformer used to pump out DC, but now it pumps out AC.

I presume this means that even if I get a full set of halogen bulbs, it will work, but it's on it's last legs (and possibly not safe? I've no idea!)

 

[classic33]

Would the LED's have worked fully lit if a bulb were to go?

 

[Yellow Saddle]

I presume this means that even if I get a full set of halogen bulbs, it will work, but it's on it's last legs (and possibly not safe? I've no idea!)

That's my guess. However, it is still safe since it only puts out 12V, perhaps 24V.

MY thought was the transformer - but @swee'pea99 is correct - hasn't occurred to me for some reason that the remaining bulb that doesn't work might be the issue. Also possible that with only 3 bulbs in the resistance is too low, or something?

The bulbs are connected in parallel. If one blows, the others continue to work. All that happens is that collective now draws less current.

 

[GrumpyGregry]

Other retailers sell very similar products so if it is knacked it can be replaced. tlh wouldn't let me have one in the dining room. Flush mounted LED spots instead.

 

[fossyant]

We have one of those wire type lights in the conservatory. Certainly try replacing all the bulbs first.

 

[Yellow Saddle]

Eliminate the guessing. Get a multimeter. A house without a multimeter is like a fridge without beer.

 

[KneesUp]

Thanks for all your help.

For reference:

2 x LED + 3 x working Halogen - fine
1 x LED + 2 x working halogen - fine
2 x LED + 2 x working halogen - no show

Only issue now is I bought 35w bulbs and when I was fitting them I noticed the large sticker saying Max 20w on the plastic (and therefore melt-able) shades. Back to the hardware shop ...

 

[mybike]

Thanks for all your help.

For reference:

2 x LED + 3 x working Halogen - fine
1 x LED + 2 x working halogen - fine
2 x LED + 2 x working halogen - no show

Only issue now is I bought 35w bulbs and when I was fitting them I noticed the large sticker saying Max 20w on the plastic (and therefore melt-able) shades. Back to the hardware shop ...

I'd expect the LEDs to draw less current. Could it be something to do with the sockets rather than simply the lamps?

 

[KneesUp]

I don't think so - the socket only runs two sets of lights. The LEDs are very old - from when LEDs first became viable as lighting, and it's never been able to run with more than 2 out of 5 using them.

 

[subaqua]

LED generally require a driver . they can run on transformers but do strange things to the harmonics which will cause certain combinations to not work.

230V GU10 LEDs work as they have an internal driver . the ELV ones need a driver matched to them .