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Switch mechanism Switch mechanism


  • Failure mode Kettle does not automatically switch off, is too slow to switch off or kettle will not switch on.
  • Durability feature Use tested and reliable controls.
  • Cost

Good practices

  • Good practicesUse controls from reputable suppliers
  • Good practices Test new designs for 20.000 cycles
  • Good practices Welded bus-bar connections

Bad practices

  • Bad practicesAvoid using untested connector and control mechanisms

Key facts

  • The return rate can be as high as 30% for a bad design.
  • 22% of consumers check on-line reviews before buying to avoid unreliable brands.

Icon key

  • Failure mode Failure mode
  • Durability features Durability features
  • Cost saving Cost saving
  • Low cost Low cost
  • Cost neutral Cost neutral
  • High cost High cost

Key failure modes

Early life

Defective designs of new kettles can take too long to switch off. After a short period of use, this time can lengthen and eventually they do not switch off.

Causes of failure to switch off:

  • Poor kettle design, especially the design of steam pipe.
  • Sub-standard plastics used for kettle (parts distort at 100˚C, causing gaps at the lid and spout so that steam escapes instead of passing down the steam pipe).

Failure to switch on is less common in early life, but can occur if mains plugs are not wired correctly, excessive scale builds up on elements that is not removed by users or due to poor control installation.

A high rate of early switch mechanism failures (<12 months) can occur if these are poorly designed or of sub-standard quality. 

Later in lifetime

Kettle controls and connectors are supplied to kettle manufacturers as separate components. These parts include the electric contacts that connect mains power to the heating elements. The lifetime of the parts can be shortened due to:

  • Poor installation, many possible causes; contamination, physical damage, badly inserted crimp connectors, etc.
  • Use of unsuitable materials, such as cord insulation that decomposes when hot emitting fumes that contaminate electric contacts.
  • Sub-standard designs of kettle, control mechanism or sub-standard materials are used.
  • Kettle controls not installed according to manufacturers instructions.

Specification for improved performance

The specification below provides the recommended improvements needed to improve product durability. They are ranked from bronze to gold, based on the effectiveness of the change in improving durability, with bronze being the minimum.

Only use tested controls that survive required number of cycles

Ensure that switch controls will function for the required number of use cycles by fully testing all new kettle designs to ensure durability. A kettle failure rate of <3% is achievable. Beware of counterfeit controls and copies as these are likely to be unreliable.

  • Switching off -  the design and location of the steam pipe needs to allow free flow of steam but avoid blockage by scale build up. Ensure grades of plastics used are suitable so that kettle parts do not distort at 100˚C. Test to ensure durability is acceptable
  • Switching on – avoid contamination of contacts by:
  • Braze or weld contacts to heating element using rigid metal bus-bars without electrical insulation or crimps.
  • If electrically insulated flexible wire connections are used, ensure that it is resistant to high temperature.
  • Avoid leaks into the base. Patented sealing systems are available for polypropylene kettles.
  • Ensure controls are installed as specified by the manufacture, avoid damage and contamination during assembly. Ask local technical team to carry out random factory inspections.

Testing to demonstrate performance

Kettle testing as described for lids will also test kettle controls. The test used is fill / boil / empty with lid opening and closing and this is carried out on the required number of cycles for kettles. Descale as necessary during test.