The Ghost in the Machine

While the recent $11.5 M civil penalty agreement between Whirlpool and the CPSC certainly raised some eyebrows, what caught my attention are the technical issues behind this penalty. The CPSC’s press release stated that Whirlpool did not immediately report glass cooktops that could turn on by themselves. The company received 157 reports of this issue, including 14 reports of property damage, four reports of objects igniting, and two reports of minor burns.

Clearly, any heating appliance that can turn on by itself could create a serious hazard. And while this seems like a highly unusual event, spontaneous activation of appliances is not as uncommon as one might think. From toaster ovens to electric ranges, there have been numerous cases that have baffled both consumers and manufacturers. Could it be a ghost in the machine?

After investigating several of these issues myself, my theory is that spontaneous activation is often caused by EMI or electromagnetic interference from spurious communication signals in the home. Our homes have become electrically noisy environments. Long gone are times when running the vacuum cleaner caused electrical interference in the old picture tube TV. But along came cordless phones, mobile phones, Wi-Fi, Bluetooth, Zigbee and other wireless technology sources of electrical interference that can potentially trigger unshielded appliances. While rare, the frequency with which this happens is still concerning and gives indication that the standards and pre-sale testing protocols for immunity to electrical interference need to be strengthened.

When a consumer complains about spontaneous activation, the challenge for manufacturers is in determining the root cause of the problem. I have had my own frustrations trying to replicate spontaneous activation issues in a laboratory while testing several appliances claimed to have had this problem. The challenge is often that the laboratory environment is not the same as a home environment where, perhaps, spurious over-the-air signals activated an appliance without human interaction. If manufacturers can’t identify the root cause of the problem, or even replicate the consumer’s experience, how would they know what to fix in the event of a recall corrective action?

While this may not have been the situation in Whirlpool’s case, the above scenario does challenge manufacturers in determining whether or not the issue is reportable to the CPSC. Does the product really have a safety defect? Could the consumer’s claim have been false? Could the consumer have accidentally activated the appliance, which often happens by unintentionally bumping into the range control knobs? Could the issue be unique to one consumer’s environment and highly unlikely to occur elsewhere? It takes time and good technical skills to verify claims of spontaneous activation.

Best practices dictate immediately launching an in-depth investigation into the environment in which this happened and attempting to replicate it in the laboratory. Closely monitoring and analyzing all similar complaints can help inform an investigation. If a company suspects EMI is the culprit, it would be wise to test the product under the most rigorous international standards, and include beta testing outside of the laboratory under all modes of operation. Most importantly, report to CPSC any issue that can create a serious hazard, even if you have not verified that a product defect was the root cause. A regular mantra of the CPSC is: “When in doubt, report!”