The Clocks Go Back This Sunday: Two Electrical Checks That Take A Minute

The clocks go back an hour on Sunday 25 October. It is the one date in the year that everybody remembers without being reminded, which is exactly why the CRU and ESB Networks tie two safety checks to it.

Their advice is to carry out these tests twice a year, when the clocks change: test your trip switch or Residual Current Device by pushing the test button, and test your smoke and carbon monoxide alarms. Both take under a minute. Most homes do neither.

How do you test an RCD, and what should happen?

Go to your board. The RCD is the wider switch, usually with a small button marked T or Test on the front. Press it.

The RCD should trip immediately and cut the power to everything it protects. That is the whole test. Push it back up and you are done.

What you are checking is mechanical. An RCD watches for current leaking to earth, the kind of leak that happens when electricity finds a path through a wet fitting, a damaged cable, or a person. It is designed to cut off in milliseconds. But it is a device with moving parts that may sit untouched for years, and a device that has never been operated can seize.

Two things to know before you press it. Everything on that side of the board goes off, so save whatever you are working on and be aware of anything that does not like losing power. And if the RCD does not trip when you press the button, stop treating it as a working safety device, because it is not one. That needs looking at properly, and a registered electrical contractor can test the installation and certify it.

If it trips but will not reset, you have a live fault rather than a stiff button, and that is fault finding territory.

Why test the smoke alarms at the same time?

Because the numbers are not comfortable reading. Fire deaths in Ireland rose to 34 in 2025, up from 25 in 2024, according to the National Directorate for Fire and Emergency Management. Fire brigades attended 21,794 fires that year, of which 4,131 were in people's homes.

Keith Leonard, National Director for Fire and Emergency Management, put it plainly: "Smoke alarms remain the single most important life-saving device in the home. While many homes are equipped with alarms, it is essential that they are properly maintained and regularly tested to ensure they operate effectively when needed."

The NDFEM's top advice is to install at least one smoke alarm on every level of your home. Testing them is the part that gets forgotten, because an alarm that is silent looks identical to an alarm that is working.

Press the test button on each one. It should sound loudly and immediately. Walk the house and do every alarm, not just the one at the bottom of the stairs, and if you have a carbon monoxide alarm, test that too.

What if an alarm does not sound, or keeps chirping?

A single chirp every thirty seconds or so almost always means a low battery, and in a sealed ten year alarm it means the whole unit has reached the end of its life and needs replacing rather than opening.

An alarm that does nothing at all when tested is worse than no alarm, because you think you are covered. Replace it.

If your alarms are the mains-wired interlinked type, where one sounding sets off the rest, test one and check the others follow. Interlinking is the part that matters at three in the morning, when a fire starting in the kitchen needs to wake somebody upstairs. If you are thinking about upgrading what you have, that falls under smoke and heat alarms.

While you are at the board anyway

A few things are worth a look once a year, and this is as good a moment as any:

• Is anything warm to the touch, discoloured, or does the board smell of hot plastic?
• Are any of the switches sitting at half mast rather than fully up?
• Is the board itself an older one with rewireable fuses and no RCD at all? Plenty of Irish homes still have these, and they offer no protection against a leak to earth.
• Can you actually get at the board in a hurry, or is there a coat rack in front of it?

None of that requires taking a cover off. Do not take the cover off.

Common questions

How often should an RCD be tested?

The CRU and ESB Networks advise twice a year, timed to the clocks changing in spring and autumn so it is easy to remember. It takes seconds and it is the only way to know the device still operates.

My RCD trips when I press the test button but the power goes off for the whole house. Is that normal?

It depends on how the board is arranged. In some installations a single RCD covers everything, so testing it kills the lot. In others the circuits are split across two, so only half goes off. Both are normal. What is not normal is nothing happening at all.

Do ten year sealed smoke alarms still need testing?

Yes. The ten year rating is the battery life, not a guarantee the unit is still working. Test it like any other alarm, and note the expiry date printed on the back, because once it passes the alarm should be replaced rather than kept going.

Should I test the alarms after the clocks change or before?

It genuinely does not matter. The point of tying it to the clocks is that it happens twice a year without anybody having to remember a date. Do it on the Sunday while you are going around changing the oven and the car.

Two minutes, twice a year

That is the entire commitment. One button in the board, one button on each alarm. If everything responds, you have confirmed that the two things standing between your household and the worst kind of evening are actually working. If something does not respond, you have found it now rather than the hard way.