In many kitchens I have seen a short-time timer attached to the outlet where the coffee maker/percolator/water boiler is connected. I.e. to make coffee, they both need to start the coffee maker, and start the timer (which will be on for example 30min).

I understand the reason for this, which is to prevent fire which can be caused by letting for example the hotplate in the coffee maker run hot without anything on it, or the water boiler be on without any water in it.

However in most modern coffee makers/water boilers/percolators there is a built in timer. For example in my percolator, there is a built in timer and the percolator will automatically turn off after 15min. So is there still a good reason to use an external short-time timer (even if there is a built in one) or can this be considered to be over cautious?

I live in Sweden so the appliances I buy follow the EU regulations.

  • 3
    different places on this planet have different regulatory regimes for appliances (and get different stuff that may be more or less reliable as a result) Commented Oct 9, 2017 at 11:42
  • Ahh, ok :) Im in Sweden, in the EU, so my guess is that stuff are rather reliable (given that I buy approved appliances, which i do as far as i know)
    – Cleared
    Commented Oct 9, 2017 at 11:45

2 Answers 2


If the appliances have their own timers built in, then I don't think an additional in line timer adds significant safety or energy efficiency. And given that any device can malfunction, any additional device can introduce risk. If you already have a built-in timer, then most of the time I would keep it in the indefinite on position if the other appliances have their own timers.

My sister has an electric hot water kettle which boils one quart to two quarts of water quickly and then keeps it near boiling. This is an energy efficient method for producing boiling water, but is an extra appliance cluttering the kitchen counter top.

I boil water on the kitchen stove and set the timer to alert me at a preset time. Sometimes I forget the kettle on the stove with the result that a lot of water vapor and heat is added to the air in the room.

  • "And given that any device can malfunction, any additional device can introduce risk." Generally additional devices are used for redundancy as it is assumed that, while the chance of any individual device failing may be non-negligible, the probability of all devices in the safety chain failing is much less.
    – JAB
    Commented Oct 9, 2017 at 15:37
  • @JAB I think the risk referred to in this case is of an electrical fault causing a fire. Redundant timers would indeed reduce the risk of a fire resulting from timer malfunction. Commented Oct 9, 2017 at 16:54

I think you have two time periods mixed up. The short timer at the outlet is going to limit time from the activation to set timer period. During that time the attached appliance may be powered.

On the other hand the timer in the type of appliances that you describe is a delayed start time to when the process can be started.

So envision that a 30minute timer at the wall is set to 30minutes at say 9PM. You try to set the appliance to kick on at 6AM so there would be hot coffee when you wake up. It could never happen because the wall timer shut everything off at 9:30PM.

  • 2
    I think you missunderstood the question. Both the wall timer and the timer in the appliance are short-time-timers. I.e. not used for schedule power at specific times, but rather to set a timer for "on for 30 min"
    – Cleared
    Commented Oct 9, 2017 at 11:43

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