Low Voltage Down Lights - Fault

[cyclingcyclops]

The 6 low voltage lights in my bathroom all 'went out' simultaneously. They were NOT switched off, but simply 'went out' as I was bathing. Circuit breaker is not tripped, and bulbs are not blown. This is the second time this has happened since the bathroom was recently refitted. The first time the installer came back to repair, however I have lost all confidence in them and so wondered if anyone out there had any ideas?

 

[ban-all-sheds]

low voltage lights

I'm assuming you mean extra low voltage, probably 12v.

How many transformers?

 

[cyclingcyclops]

6 low voltage (12v) downlighters with dedicated transformers (i.e. 1 per light), sold together, i.e. as a single unit (suggesting transformer is correct rating for light).

 

[ban-all-sheds]

Unless they are all cutting out due to overheating at exactly the same instant it looks like there's a wiring fault before them.

Are they on a dimmer switch?

6 low voltage (12v) downlighters

That is not low voltage.

 

[cyclingcyclops]

Firstly thanks for the speedy responses.

Secondly - They were on a dimmer - but in an attempt to discount a switch problem, this has been replaced with normal switch, yet the lights will still not come on.

 

[ban-all-sheds]

Do you have a multimeter and a knowledge of how lighting circuits are wired?

 

[cyclingcyclops]

I have a multimeter, although never used it for AC and I have a basic understanding of lighting circuits.

 

[ban-all-sheds]

You need to start following the lighting circuit back until you find the loose connection or broken cable probably causing this.

Is access to the circuit easy? Does the loop run in the ceiling, or through the switches?

 

[cyclingcyclops]

"Is access to the circuit easy? Does the loop run in the ceiling, or through the switches?"

The bulk of the wiring is in the loft, with drops into a false ceiling for the extra low voltage transformers/lamps. The switch cables are sunk into the plaster. Not sure how any of this relates to 'the loop'. Can you explain?

 

[bongos]

With the switch in the off position, do you have 240v between live/switched live?

If so then find the loop in/out for the bathroom lights. this will possibly be a junction box in your attic. Do you have 230v between L/N & L/E, and 0v between N/E?

 

[cyclingcyclops]

Thanks Bongo - I'll check at the weekend (access to attic in sleeping boy's room). Meantime I will shower by candle light.

 

[ltheb]

Are the dimmer and transformer(s)compatible? Most electronic transformers tend to be dimmable now. Check rating of the dimmer, at least 400w for this set up. 'course, if it's not working with a standard rocker switch then you are looking for a loose connection.

 

[cyclingcyclops]

I now have a bit more info. Loop is definitely in ceiling/loft. There is absolutely no power to the switch. There is a scary looking junction box (no cover) in the loft which seems to have more connections than it is designed to take, and as such it is difficult to see what goes where, but there is definitely 240v between L-N, L-E, but none bewteen N-E.

 

[ban-all-sheds]

there is definitely 240v between L-N, L-E, but none bewteen N-E.

All of those voltages are as they should be.

 

[cyclingcyclops]

I know, which is why I am stumped. My only deduction is that the problem is with the connection of the switch feed to the loop. So I will need to trace this back to where it links in.