House alarm into light fuse

[paulramplin]

Hi. Just wondered if this is a normal practice -
I had to help my elderly neighbour the other night when her house alarm was triggered after a lightbulb went out and tripped the fuse. It turns out that the house alarm control pad goes into a light circuit fuse and because the fuse tripped off, the alarm then... well, alarmed.
I figure that the alarm sounded because the electric to the control pad was cut off and so it assumed there was trouble afoot. But is it normal to run the house alarm into a light circuit fuse? I mean, every time a light bulb blows, it will result in the alarm sounding, which will, in turn, mean flipping the fuse back on in order to restore power to the alarm control pad so that the alarm code can be input to turn off the alarm.....!
Thanks in advance.

 

[mwatsonxx]

As you have discovered, yes best to put them on their own circuit. You should be able to turn off the alarm due to the battery back-up.

It's unusual for a blown lamp to blow a fuse, but when filament lamps are mounted horizontally it can happen.

 

[winston1]

It's unusual for a blown lamp to blow a fuse, but when filament lamps are mounted horizontally it can happen.

I wouldn't say it was unusual, especially with cheap lamps with no internal fusing. The answer of course is to move into the 20th century and replace with a CFL, or even into the 21st century and replace with an LED.

To put an alarm on a separate circuit requires notification and loads of paperwork and hassle, so probably best where it is.

 

[paulramplin]

I wouldn't say it was unusual, especially with cheap lamps with no internal fusing. The answer of course is to move into the 20th century and replace with a CFL, or even into the 21st century and replace with an LED.

So a bulb only trips the fuse off if it's an old fashioned bulb? I had no idea. I'll replace the bulbs on that circuit with CFLs.
Thanks.

 

[ban-all-sheds]

Beware of dimmer switches and some methods of 2-way switching - CFLs may not be suitable.

 

[JohnW2]

It's unusual for a blown lamp to blow a fuse, but when filament lamps are mounted horizontally it can happen.

Possibly true if it's literally a fuse, but, for what it's worth, my past experience with incandescent bulbs/lamps (thankfully now 'history'!) is that they quite often tripped MCBs when they died, regardless of the orientation of the bulb/lamp. It used to happen to me quite a bit, but very few of my (many) bulbs/lamps were mounted horizontally.

Kind Regards, John

 

[EFLImpudence]

You say "trips" the fuse. Fuses don't trip.

A blown incandescent light bulb freqeuntly "trips" a circuit breaker but is less likely to "blow" a fuse.

 

[jg321]

...my past experience with incandescent bulbs/lamps (thankfully now 'history'!) is that they quite often tripped MCBs when they died, regardless of the orientation of the bulb/lamp. It used to happen to me quite a bit, but very few of my (many) bulbs/lamps were mounted horizontally.

One of my more frustrating experiences was the landing light doing this to me on a 2am trip (pardon the pun!) to the toilet. It was a rewirable fuse that blew, and just as I started falling back asleep, after getting back into bed thinking "I'll sort this in the morning", I remembered that the house alarm is on the only lighting circuit. Shortly followed by a 2:30am rewire of a 5A fuse.

Incidentally, to the OP - your alarm probably shouldn't have gone off due to a mains failure. What's likely happened is that the backup battery in the panel needs replacing, so when you lost mains power, the panel lost power totally, which resulted in the bell box alarming using the power from it's own battery. You probably want to look into checking/replacing the backup battery in the alarm panel to prevent the alarm doing this in future power cuts.

Edit to add: the landing light wasn't horizontal, and it still blew the fuse. In fact, none of the lights were horizontal in that house, and filament lamps blowing often blew the fuse, or more recently, tripped the breaker.

Also to add, I'm definitely in the camp of putting important circuits such as alarms, freezers etc on circuits which you're likely to notice have lost power, so a lighting circuit seems like a good plan - edit to add: for an alarm supply!

 

[JohnW2]

Edit to add: the landing light wasn't horizontal, and it still blew the fuse. In fact, none of the lights were horizontal in that house, and filament lamps blowing often blew the fuse, or more recently, tripped the breaker.

Similiar to my experience, then. As I said, very few of the ulbs/lamps in my house have ever been horizontal. Although I don't recall many, if any, instances of fuses blowing, but once I had changed to MCBs/RCBOs it became fairly common for a dying incandescent bulb/lamp to trip the device.

Also to add, I'm definitely in the camp of putting important circuits such as alarms, freezers etc on circuits which you're likely to notice have lost power, so a lighting circuit seems like a good plan!

There are obviously arguments on both sides, but, as I often say, my personal view is usually, on balance, the same as yours. Having said that, for the reasons mentioned above I would probably be hesitant to advise someone to put an alarm etc. on a lighting circuit which had incandescent bulbs and an MCB or RCBO, particularly if they were in the habit of leaving any of the lights on when the house was unoccupied.

Kind Regards, John

 

[jg321]

I would probably be hesitant to advise someone to put an alarm etc. on a lighting circuit which had incandescent bulbs and an MCB or RCBO, particularly if they were in the habit of leaving any of the lights on when the house was unoccupied.

Agreed. Also, reading your quote of me made me realise that I should have clarified "so a lighting circuit seems like a good plan - for an alarm, not a freezer!". In fact I'll go back and edit!

 

[JohnW2]

Agreed. Also, reading your quote of me made me realise that I should have clarified "so a lighting circuit seems like a good plan - for an alarm, not a freezer!". In fact I'll go back and edit!

Yes, I noticed that but, although some people probably would have done, I didn't comment since I knew full well what you meant. My feelings are similar regarding freezers which I think are (particularly iif the freezer is infrequently visited, are probably usually better on a 'constantly used' (not 'lighting'!) circuit than on a dedicated circuit. However, I'm even more keen on freezer alarms, since they will alert one (if one is at home**) to failure of the freezer as well as failure of its electricity supply.

** mind you, in this day and age I suppose one could have an alarm alerting one to a problem even when was holidaying on a Pacific island

Kind Regards, John

 

[EFLImpudence]

Yes, I noticed that but, although some people probably would have done,I didn't comment since I knew full well what you meant.

However, other people reading it may not.

Why do you not think mistakes should be corrected?

Oh dear, it's Thursday again.

 

[JohnW2]

However, other people reading it may not.

Very true.

Why do you not think mistakes should be corrected? Oh dear, it's Thursday again.

You seem to be trying to bring the weekend forward!! In this case, the only 'mistake' was a failure to be totally clear/explicit. I imagine that many people (like me) will, in context, almost subconsciously have assumed an (implied at the time, but now explicitly added by jg321) "... for an alarm supply" at the end of the sentence.

Kind Regards, John

 

[sparkwright]

Beware of dimmer switches and some methods of 2-way switching - CFLs may not be suitable.

You'll have to remind me how CFLs aren't suitable with some methods of 2-way switching - I've gone blank for the moment...

 

[JohnW2]

You'll have to remind me how CFLs aren't suitable with some methods of 2-way switching - I've gone blank for the moment...

I had to ponder that for a while. I eventually concluded that BAS was probably referring to the 'old' method of arranging 2-way switching, which results in 'unpaired' L and N conductors - and this might facilitate induced voltages/currents high enough to cause at least flickering in CFLs or LEDs when they are 'switched off' ...

... or maybe he was thinking of something totally different!

Kind Regards, John