I was woken up very suddenly at 05:15 one morning last week by a klaxon going off, very loudly indeed. It wasn’t the smoke alarm, as that makes a different sort of beep, which meant it had to be the burglar alarm. Which was very odd, as I was sure I hadn’t actually set it the previous night before going to bed. With the noise ringing in my ears, I put the bedside light on. Or at least tried to – all I got was a dim crepuscular glow out of it. Even more odd. Fortunately, I keep a torch within easy reach, and with its aid I went to turn off the alarm and investigate the cause.
About half the lights in the house weren’t working at all, and the rest were producing at best a dull glimmer. The oven was making a dreadful noise, so I turned it off at the main fuse box, but the mains-powered clock on the microwave was still ticking away happily. I phoned the helpline number for the electrical distribution company, but they had no knowledge of any power faults in my area. It wasn’t just me though – I could hear the burglar alarm on next door’s house screaming away. The woman on the phone line and I agreed that it was most probably a prolonged brown-out, where the voltage on the line drops but doesn’t fail altogether. At that point, next door’s burglar alarm finally fell silent, and my house lights came on as the power supply went back to normal.
It seems to me that a brownout is indeed the most likely cause. Some of the newfangled energy-saving bulbs I’ve got won’t work with dimmer switches, and they were presumably the ones that failed to come on at all. The ones that were glowing dimly were therefore likely to be slightly fancier bulbs which do work with the reduced voltage that a dimmer switch provides. Some of my devices (e.g. the microwave) can clearly cope with low voltage, and kept going, but others (such as the oven) objected strongly. But I was concerned that my burglar alarm had gone off – it’s got a battery back-up which is meant to kick in to provide continuity through a power cut. That’s the trouble with the neighbour’s one – the battery is knackered and won’t hold its charge, so the alarm goes off with every single power-cut, no matter how short; and we get a lot of those up here on the top of the hills. However, I couldn’t tell how long the power had been faulty. If it had been a long time then it’s reasonable for the alarm to have discharged the battery.
I decided the best thing to do was to get someone around to service the alarm and check on the battery condition. So I took Monday off work and arranged for a technician to call. He thoroughly tested the alarm system and gave it all a clean bill of health. Apparently, my battery is holding its charge well, and doesn’t need replacing for at least another two years. So we’ll just have to put last week’s Unfortunate Incident down to a long-duration brownout.
I do hope it doesn’t happen too often – it’s a horrible way to wake up and put me in a filthy mood for the rest of the day! But at least I suppose I know that the burglar alarm works!
