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REFRIGERATOR FIRES TRIGGER RECALL

The recent refrigerator recall by Inglis, Whirlpool, and Kenmore units manufactured since 1978, to correct a problem in the butter warmer electrical circuit is discussed in this article. It provides the details and the results of six fire investigations conducted by Walters Consulting Corporation.

The purpose of the butter warmer is to allow butter to be stored in the door of the refrigerator with the temperature inside the butter compartment warmed by a heating coil. The concept was very good from a consumer's point of view as butter could be kept soft at a controlled temperature without leaving it in a cupboard at room temperature where it could be attacked by bacteria. However, the design of the electrical circuit required special consideration as there was a need to provide power to the heating coil in the door and at the same time deal with the fact that the door was hinged and the butter warmer was somewhat remote from the source of power.

 

Early Problems

Early indications of a problem with the butter warmer circuit occurred in Walters Consulting's forensic investigations in 1984. At that time, two fires were caused by arcing in the butter warmer electrical circuit.

Another more significant fire occurred in 1985 and resulted in a major controversy. At that time, the origin of the fire was determined from a scientific examination of the burn pattern, a fire spread analysis, and from evidence of arcing in the butter warmer circuit. Walters Consulting concluded that there was a problem with the design of the circuit. No action was taken by the manufacturer at this time.

 

Design Deficiency

In particular, the circuit had two connectors that allowed the assembly of the refrigerator door to be completely separated from the body of the refrigerator and then connected on the assembly line. The wiring in the door was fed through the bottom hinge and connected in a trough at the bottom of the refrigerator with the wiring from the main source of power. The location of the connectors allowed moisture to gather and to feed (by capillary action) into the connectors. It was concluded that the moisture eventually allowed for a low amperage leakage current to occur. This leakage current let to arcing and then created the fire.

The refrigerator problem continued. Walters Consulting Corporation investigated an additional four fires that were caused by the same problem in refrigerator butter warmer circuits. The investigations resulted in the same conclusion. That is, the design of the butter warmer circuit was flawed.

It was the results of these detailed investigations and the persistence in holding to the conclusion of the cause of the fires that assisted in the recall announced on March 9, 1993.

It is this type of cooperative team effort that results in product design improvements and increased public safety.

 
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Information contact: engineering@waltersforensic.com