Aquarium Water Heater Failure Analysis


An aquarium water heater allegedly overheated and exploded, causing a fire at a residential home.

Services Provided

Rimkus Consulting Group was retained to examine the evidence from the subject fire and to evaluate the findings of the other fire origin and cause experts. Rimkus performed testing using exemplar aquarium heaters and an aquarium hood.

  • In one series of tests, aquarium heaters were modified in order to cause shorting of the terminals together inside the heater tube.  These tests showed no evidence that shorting created any significant risk of an external fire.
  • In a second series of tests, exposed heater terminals were shorted together while positioned against or very close to the surface of the exemplar aquarium hood.  These tests caused only superficial damage to the hood material and did not cause ignition of the hood material.
  • A third series of tests was designed to simulate a fire source that was not from the aquarium heater which could result in aquarium water loss and subsequent heat attack to an energized aquarium heater.  In these tests, unmodified heaters were energized and then exposed to heat from an external fire source.  Within a few minutes, the rubber grommet and terminals separated from the tube.  The insulator separating the terminals also fell away with the tube, making it very easy for the terminals to arc together during tube separation.  In one such trial, the terminals spontaneously arced during tube separation.

Based upon testing using exemplar aquarium heaters and an exemplar aquarium hood, Rimkus concluded the following:

  • An electrical short inside the aquarium heater cannot reasonably be expected to ignite the aquarium hood.  
  • Arcing of the aquarium heater terminals can easily occur due to an external fire attack.

National Practice Leaders

Samuel L. Sharpless

P.E., C.F.E.I.

Vice President, Electrical Division