Hack My House: UL Certification And Turning The Lights On With An ESP8266

It’s hard to imagine a smart house without smart lighting. Maybe it’s laziness, but the ability to turn a light on or off without walking over to the switch is a must-have, particularly once the lap is occupied by a sleeping infant. It’s tempting to just stuff a relay in the electrical boxes and control them with a Raspberry Pi or micro-controller GPIO. While tempting, get it wrong and you have a real fire hazard. A better option is one of the integrated WiFi switches. Sonoff is probably the most well known brand, producing a whole line of devices based on the ESP8266. These devices are powered from mains power and connect to your network via WiFi. One disadvantage of Sonoff devices is they only work when connected to Sonoff’s cloud.

Light switches locked in to a cloud provider are simply not acceptable. Enter Tasmota, which we’ve covered before. Tasmota is an open source firmware, designed specifically for Sonoff switches, but supporting a wide range of ESP8266 based devices. Tasmota doesn’t connect to any cloud providers unless you tell it to, and can be completely controlled from within a local network.

Certifications, Liability, and More

We’re well acquainted with some of the pitfalls of imported electronics, but one of the lesser known problems is the lack of certification. In the United States, there are several nationally recognized testing laboratories: Underwriters Laboratories (UL) and Intertek (ETL) are the most prominent. Many¬† imported electronic devices, including Sonoff devices, do not have either of these certifications. The problem with this is liability, should the worst ever happen and an electrical fire break out. The Internet abounds with various opinions on the importance of the certification — a missing certification mark is somewhere between meaningless and a total hazard. The most common claim is that a house fire combined with non-certified equipment installed would result in an insurance company refusing to pay.

Rather than just repeat this surely sage advice from the Internet, I asked my insurance agent about uncertified equipment in the case of a fire. I discovered that insurance agencies avoid giving definite answers about claim payments. The response that came back was “it depends”: homeowner’s insurance covers events that are accidental and sudden. If a homeowner was aware that they were using uncertified equipment, then it could be categorized as “not an accident”. So far, the myth seems plausible. The final answer from the insurance agency: it’s possible that a non UL-certified device could result in denial of payment on a claim, but it depends on the policy and other details– why take the risk? Certification marks make insurance companies happier.

I also talked to my city’s electrical inspector about the issue. He commented that non-certified equipment is a violation of electrical code when it is hard-wired into a house. He echoed the warning that an insurance company could refuse to pay, but added that in the case of injury, there could be even further liability issues. I’ve opted to use certified equipment in my house. You’ll have to make your own decision about what equipment you’re willing to use.

There are some devices on Amazon that claim to have certification, but searching the certification database leads me to believe that not all of those claims are valid. If in doubt, there is a searchable UL database, as well as a searchable Intertek database.
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Old Wireless Switches Join The Internet Of Things

Just about any appliance comes in an internet enabled version nowadays. However, even the oldest gear can be switched on and off with an Internet connected power socket. [Bill] is in the process of automating his home, and found some old radio controlled power sockets that badly needed to join the 21st Century. Hacking ensued.

The first set of switches [Bill] came across were easy to work with. Eager to keep things as functional as possible, ESP8266s with Tasmota firmware were wedged into the enclosures. With a bit of circuit sleuthing, [Bill] was able to set up the switches to respond to commands from both the ESP8266 as well as the original push buttons and radio remote.

[Bill] later came across some black switches, which were not up to his standards. These switches were gutted entirely, being used only for their mains plug and enclosure. The relays inside were replaced with 5V versions which were easier to trigger from the ESP8266’s outputs.

[Bill[ readily admits that the cost benefits over buying off-the-shelf Sonoff modules don’t really add up, but good hackers rarely let such concerns get in the way of a fun project. Around these parts, we see plenty of hacks to automate your house – like this zero-intrusion light switch mod. Happy hacking!