Sonoff is a system that comes up often on this stack. However, I notice it seems to be of unusually low cost, not available in retail shops, sold widely in the "dodgy side of the internet" (eBay, Amazon Marketplace, Ali, etc.), and I only ever see the fairly meaningless CE mark on it.

The very first rule in NEC makes use of approved equipment mandatory. Virtually all authorities required for "approving" things delegate the job to UL and other reputable testing labs such as CSA, TUV etc.

Is Sonoff equipment actually listed by UL or other reputable testing lab?

  • Does it have a UL symbol printed on it or its packaging. One can assume that If it does than it is, if it does not then it is not. – Alaska Man Dec 14 '18 at 22:09
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    Can you check at ul.com/database ? – batsplatsterson Dec 14 '18 at 22:37
  • Sonoff is NOT UL listed. For evidence of that fact type “sonoff UL listed” into google. As best I can tell Sonoff is also far more popular in Europe than the USA, I don’t know if they carry a CE mark or not, but they don’t appear to have the mark printed on. – Tyson Dec 14 '18 at 23:19
  • From reading the CE mark is a agreement to conform to standards, no testing requirement and the manufacturer self certifies, that's why the mark is considered meaningless here in the U.S. – Ed Beal Dec 15 '18 at 20:42

No listing for UL, ETL or CSA listing just the meaningless CE , I also did not see an FCC certification when trying to look up there noise emmision / band with certification, these things should not be any place other than China.


The NEC does not require UL listing, but it may, depending on the type of product, require "listing" by what's referred to as an "NRTL", Nationally Recognized Testing Lab, of which UL is the most widely known. But the NEC only applies to premises wiring, so these devices that must be hard-wired into your house would not be code compliant. It would not apply to anything that is "plugged in" to a wall socket or screwed into a lamp socket.

Where UL / NRTL listing of plug-in devices does play a part however is in your homeowner's insurance. UL stands for Underwriter's Laboratories, as in insurance underwriters. If something causes a fire and the insurance carrier does an investigation and can trace the source of the fire to a non-listed device, they can refuse to pay out on the damages. That happens more than you might think.

  • The fact is the NEC does require listing. UL is the gold standard in the U.S. for equipment manufactures TUV is commonly used for certification of equipment manufactures products that are small in numbers. NEC covers more than wiring it covers the devices also. There are reasons you don't find non listed devices at stores in the U.S. because of the liability. – Ed Beal Dec 15 '18 at 20:39
  • @EdBeal NEC requires listing for some things, not all -- there are specific listing requirements scattered throughout the NEC, but other things can simply be approved by the AHJ. (Granted, though, most AHJs will use UL listing as a strong guide to their own approval of a device.) – ThreePhaseEel Dec 16 '18 at 3:22
  • Ok when your AHJ provides written approval for these cheap non listed switches I will change my answer, don't think it is going to happen. A recent job the owner wanted me to install a non listed transfer switch. I could not do it. He found a contractor that tried but after 3 failed inspections a listed switch was installed. The switch was in a location 50' from the home next to the vault so you be the judge. Not listed is not listed. – Ed Beal Dec 16 '18 at 14:24

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