SEVEN GU10 halogen lamps all blew together!

[JBR]

I went to the bathroom this evening and turned on the lights only to hear a 'pop' and all SEVEN GU10 halogen lamps had blown.
I assume that this was the case, rather than the fuse or circuit breaker, as the fan continued to run.
I realise that halogens on the same circuit can blow together, in fact just a couple of weeks ago two of them in a standard lamp went at the same time, but SEVEN?
Is that possible or could it be something else?

 

[SUNRAY]

I went to the bathroom this evening and turned on the lights only to hear a 'pop' and all SEVEN GU10 halogen lamps had blown.
I assume that this was the case, rather than the fuse or circuit breaker, as the fan continued to run.
I realise that halogens on the same circuit can blow together, in fact just a couple of weeks ago two of them in a standard lamp went at the same time, but SEVEN?
Is that possible or could it be something else?

If all 7 blew quickly and at the same time, I'll guess the fault is quit catastrophic. I suspect it's something else like a fuse.
Are these 230V or 12V?

 

[JBR]

If all 7 blew quickly and at the same time, I'll guess the fault is quit catastrophic. I suspect it's something else like a fuse.
Are these 230V or 12V?

Thanks for your response. They're 230V.
I wondered whether it could have been a break or a short in the wiring. It was quite a loud pop.

 

[securespark]

They're not on a dimmer?

 

[SUNRAY]

Thanks for your response. They're 230V.
I wondered whether it could have been a break or a short in the wiring. It was quite a loud pop.

I was hoping 12V as it would point to a transformer/driver. It does point to a break as you say or maybe the switch. This isn't on a dimmer by chance?

EDIT: Done it again, crossed in the post.

 

[ericmark]

Interesting post, I had talked about LED GU10 lamps failing at the same time due to a surge, but quartz halogen is unlikely caused by what we think of as a surge which in the main is for a very short time so may effect LED but unlikely to effect tungsten.

I know loss of PEN can cause this, but would expect more to fail.

So can't think of any situation which would cause this.

 

[JBR]

Thank you all. Solved now.
It was a fuse after all, in the switch unit, and one only of the lamps had blown.
What threw me was that after all the lights went out the fan continued to turn. I can only assume that the circuit within the fan which keeps it turning for a few minutes after the lights are turned off must be unfused and can only be isolated from the circuit breaker. I assume this is normal?

 

[ericmark]

Tungsten lamps can when they fail cause ionisation of the gas inside the envelope, this is seen as a bright flash when the lamp fails, this can be a huge current, there was suppose to be a fuse built into the bulb which would rupture stopping other bulbs failing, however fuses are often slower than the magnetic part of a circuit breaker, so with a B6 circuit breaker looking at 30 amp to trip magnetic part, but only takes 0.01 seconds, so as we moved from fuses to circuit breakers the fuse in the bulb became pointless to stop the MCB tripping.

Today with LED again we have fuses in the bulb, normally in the form of a resistor, mainly to stop thermal run away, I am still with this house using up my stock of tungsten bulbs, but have very few left, mainly in rooms hardly used.

 

[securespark]

JB... Are the bathroom lights fed via a fused connection unit?

 

[JBR]

JB... Are the bathroom lights fed via a fused connection unit?

Hi, SS. Yes, all seven lights along with the fan are fed from the fuse within the switch.
You're going to tell me to use a 5A fuse rather than 3A, aren't you?

 

[plugwash]

I assume this is normal?

I would place it in at least the category of "strange".

Normally there are not fuses in UK lighting circuits, however some fan manufacturers have instructions that demand 3A fuse protection. Many people think these instructions are silly (or even "wrong"), some go as far as advocating ignoring them. There is also an argument though that by ignoring the manufacturers instructions you are leaving yourself exposed in the unlikely event that things go horribly wrong with the fan and it burns the house down. Some installer don't want to take that risk so they do their best to follow the instructions.

Unfortunately the instructions generally don't tell people how to achieve this fusing down and it's not immediately obvious. So often people end up with setups where the fuse only protects one of the two feeds to the fan, rendering it a bit pointless and confusing. IMO the best thing to do if fusing down for a fan is to put the fuse in front of the whole light and fan setup, either by using a separate unswitched FCU and light switch or by using a modular range that allows the components to be connected separately.

 

[securespark]

Hi, SS. Yes, all seven lights along with the fan are fed from the fuse within the switch.
You're going to tell me to use a 5A fuse rather than 3A, aren't you?

No.
Is the FCU off the lighting circuit?

 

[EFLImpudence]

The "manufacturer's instructions" nearly always state the the item "must be installed by a qualified electrician" but no one ever seems to care about that one.

 

[Mottie]

Whenever one of my halogen bulbs in the kitchen blew when switching on, there was always a 'pop' and the breaker would trip. It also trips if a normal incandescent bulb blows when switching on although there is never a 'pop'. Perhaps the OP's fan has a switched live from the lights but a main feed from elsewhere?

 

[JBR]

Unfortunately the instructions generally don't tell people how to achieve this fusing down and it's not immediately obvious. So often people end up with setups where the fuse only protects one of the two feeds to the fan, rendering it a bit pointless and confusing. IMO the best thing to do if fusing down for a fan is to put the fuse in front of the whole light and fan setup, either by using a separate unswitched FCU and light switch or by using a modular range that allows the components to be connected separately.

That's the case in our setup, except that the 'run on' for the fan when switched off is not 'fused' (apart from the consumer unit). I suppose that it is just possible that there is a separate fuse for that circuit inside the fan itself?