LV Downlighters & melted choc blocs

[walec]

Hi, just been to a customer who has some LV dowlighters in the kitchen and playroom not working, replaced the bulb, no luck, pulled it out and found the connection in the choc block between the transformer and bulb had melted, not seen this before, there are four in total and they are all the same, any ideas on why? would be appreciated. would you replacce the choc bloc or the transformer as well? Thanks

 

[ezzzekiel]

what was the choc rated at

 

[mogga]

take the rest down and chech then if theres 4 damaged the rest may be on the way to seriuos damage

 

[walec]

I recon 3A, swap for 5A you think?

 

[walec]

Mogga, I agree, I will take the rest down, I have done nothing yet as if I have to replace the transformers we are talking about 40 lights! I am just trying to understand why before I do anything.
These transformers also are connect straight to the radial, if I replace transformers I will have to put JB`s in as the transformers I have have wires coming out not terminals as the existing.

 

[mogga]

swap for 5a and make sure when fitted that the block is far enough away from the lamp to prevent heat also mind insulation ect

 

[Spudnik]

I would hazard a guess at the choc blocks being too near the lamp.

 

[AndrewMgan1976]

The 40 lights aren't on the one circuit are they?

 

[eddielarge]

i agree with jason just sounds like damage from lamp

 

[walec]

Hi Guys, no the lights are not on one circuit, hard to say about the choc blox being too close to the lamps, they are in a plastic housing which shows no sign of damage and is held in position by a bracket.

 

[bugsy]

Proberbly due to initial loose connection or possibly the choc too close to lamp

 

[andekoch]

loose connection seems the problem. 5amp (and smaller) connector blocks have a horrible habit of working loose in my experience. I now use 15amp connectors as a minimum and have no hassles with terninals coming loose or wires not being firmly gripped, also a strip of 4 fits into the chock box.

common heat cause is bulbs in the downlighters being changed from aluminum reflector (hot) types to 'cool' bulbs (which are the most common apparantly), this then allows the heat from the bulb to go up into the fitting and not be reflected down into the room.

 

[fazhols]

Another factor here could be the head build up in the connector (which isnt up to the job). Most do not realise that if the chock blocks are held in place (as with the chocbox) then you are only supposed to use chock blocks that have been tested and certified to pass the heat build up test. (this is specified in BS 60670-22 :Clauses 16.102 :

“16.102 Connecting devices integrated or incorporated in connecting boxes shall be so constructed that the temperature rise in normal use does not exceed the value specified in16.102.4.”

According to BS7671 chocbox can not comply as the manufacturer does not specify which connectors can be used with his product! (e.g. WAGOBOX specifies wago connectors only). The only enclosures exempt from this are ones where the connectors remain "free floating".