4 ms·

Regarding your first point, the relay has 2,000V of coil-to-contact isolation: https://omronfs.omron.com/en_US/ecb/products/pdf/en-g5le.pdf https://omronfs.omr

Regarding your first point, the relay has 2,000V of coil-to-contact isolation: https://omronfs.omron.com/en_US/ecb/products/pdf/en-g5le.pdf https://omronfs.omron.com/en_US/ecb/products/pdf/en-g5le.pdf Though it does look like the clearance/creepage distances on the PCB to the low-voltage ground plane are not any wider than 2mm or so, which is acceptable for 120VAC, but not acceptable for 240VAC per IPC9592. I wouldn't worry about sticking this in an enclosure and using it to turn a light on and off, but I wouldn't want to be handling it while it was live, either! Regarding FCC/UL certification, a product is exempt from FCC certification requirements if it's "A digital device used exclusively as industrial, commercial, or medical test equipment", which most development boards are. I've got some dev boards from Microchip on my bench right now which aren't FCC or UL listed, either.

tripletao 6y ago
A digital device is defined as: > (k) Digital device. (Previously defined as a computing device). An unintentional radiator (device or system) that generates and uses timing signals or pulses at a rate in excess of 9,000 pulses (cycles) per second and uses digital techniques; ... https://www.govinfo.gov/content/pkg/CFR-2009-title47-vol1/pdf/CFR-2009-title47-vol1-part15.pdf https://www.govinfo.gov/content/pkg/CFR-2009-title47-vol1/pd... This has Wi-Fi, so it's an intentional radiator, so it's not a digital device. I believe this product would be technically noncompliant if not certified, though lots of stuff like this gets sold and I've never heard of any enforcement action. Their best counterargument would be that it's a component and not a self-contained product. That seems true for many dev boards but not particularly true for this one. Since the practical risk of interference is extremely low, I'd guess the FCC is happy to leave this grey for now.
- R0b0t1 6y ago
  Test and measurement supersedes intentional emission. If it were the other way no development boards would get sold, especially necessary things like low volume engineering samples. Should a one-off need certification before it can be transferred to the company that contracted the work to build it? No. If you have never sought certification know that it is quite expensive. What seems to matter the most is if anyone actually notices interference, and if they do how widely the device ended up being sold. If a test and measure product starts making it into everybody's house eyebrows will be raised. If you misuse a test and measurement device and generate interference it is typically on you.
  - antoniuschan99 6y ago
    If it’s sold as a kit(eg. Devboard) or battery powered it doesn’t need to be certified. You also can get pre-certified boards, the wroom-02 being the pre-certified esp8266.
    - R0b0t1 6y ago
      I've seen certified development boards also, but what most don't realize is you can't combine certified parts to make a certified product. So depending on your product there is literally no benefit to getting it certified. There are things that are battery powered that need to be certified and things that are not kits that don't need to be, though, so I'm not sure I can agree with that wording.
      - tripletao 6y ago
        I think battery-powered unintentional radiators can sometimes avoid testing, but battery-powered intentional radiators definitely don't. The statement about kits is also wrong, per pdabbadabba's comment below. An intentional radiator module can get a module certification. In that case the final system still needs verification (the same kind of testing that an unintentional radiator gets), but doesn't need certification. When you see a label on the outer device that says "Contains FCC ID XXX-XXXX", that's the module's ID. https://apps.fcc.gov/oetcf/kdb/forms/FTSSearchResultPage.cfm?switch=P&id=44637 https://apps.fcc.gov/oetcf/kdb/forms/FTSSearchResultPage.cfm...
        antoniuschan99 6y ago
        Verification is Declaration of Conformity (DOC)? You can either get a Declaration of Conformity from the lab or just sign it yourself. But in the chance you get audited and it doesn't function how you said it would then you'd get in trouble
        tripletao 6y ago
        Verification and DoC are different (and apply to different types of unintentional radiators), but you're correct that neither involves filing anything with the FCC (or any private body accredited by the FCC; for real most certifications go through a TCB, not directly to the FCC). You just make the file (including any test results required) and keep it in a drawer. The FCC can come and ask for it, and if you don't have it then you're in trouble. ETA: And here's the section about battery-operated digital devices (i.e., unintentional radiators, with no radio transmitter): > § 15.103 Exempted devices. > [...] > (h) Digital devices in which both the highest frequency generated and the highest frequency used are less than 1.705 MHz and which do not operate from the AC power lines or contain provisions for operation while connected to the AC power lines. Digital devices that include, or make provision for the use of, battery eliminators, AC adaptors or battery chargers which permit operation while charging or that connect to the AC power lines indirectly, obtaining their power through another device which is connected to the AC power lines, do not fall under this exemption. And here's the section that makes it fine to build your own stuff in limited quantity, as long as you don't do anything obviously stupid: > § 15.23 Home-built devices. > (a) Equipment authorization is not required for devices that are not marketed, are not constructed from a kit, and are built in quantities of five or less for personal use. > (b) It is recognized that the individual builder of home-built equipment may not possess the means to perform the measurements for determining compliance with the regulations. In this case, the builder is expected to employ good engineering practices to meet the specified technical standards to the greatest extent practicable. The provisions of §15.5 apply to this equipment.

tripletao 6y ago

A digital device is defined as: > (k) Digital device. (Previously defined as a computing device). An unintentional radiator (device or system) that generates and uses timing signals or pulses at a rate in excess of 9,000 pulses (cycles) per second and uses digital techniques; ... https://www.govinfo.gov/content/pkg/CFR-2009-title47-vol1/pdf/CFR-2009-title47-vol1-part15.pdf https://www.govinfo.gov/content/pkg/CFR-2009-title47-vol1/pd... This has Wi-Fi, so it's an intentional radiator, so it's not a digital device. I believe this product would be technically noncompliant if not certified, though lots of stuff like this gets sold and I've never heard of any enforcement action. Their best counterargument would be that it's a component and not a self-contained product. That seems true for many dev boards but not particularly true for this one. Since the practical risk of interference is extremely low, I'd guess the FCC is happy to leave this grey for now.

R0b0t1 6y ago
Test and measurement supersedes intentional emission. If it were the other way no development boards would get sold, especially necessary things like low volume engineering samples. Should a one-off need certification before it can be transferred to the company that contracted the work to build it? No. If you have never sought certification know that it is quite expensive. What seems to matter the most is if anyone actually notices interference, and if they do how widely the device ended up being sold. If a test and measure product starts making it into everybody's house eyebrows will be raised. If you misuse a test and measurement device and generate interference it is typically on you.
- antoniuschan99 6y ago
  If it’s sold as a kit(eg. Devboard) or battery powered it doesn’t need to be certified. You also can get pre-certified boards, the wroom-02 being the pre-certified esp8266.
  - R0b0t1 6y ago
    I've seen certified development boards also, but what most don't realize is you can't combine certified parts to make a certified product. So depending on your product there is literally no benefit to getting it certified. There are things that are battery powered that need to be certified and things that are not kits that don't need to be, though, so I'm not sure I can agree with that wording.
    - tripletao 6y ago
      I think battery-powered unintentional radiators can sometimes avoid testing, but battery-powered intentional radiators definitely don't. The statement about kits is also wrong, per pdabbadabba's comment below. An intentional radiator module can get a module certification. In that case the final system still needs verification (the same kind of testing that an unintentional radiator gets), but doesn't need certification. When you see a label on the outer device that says "Contains FCC ID XXX-XXXX", that's the module's ID. https://apps.fcc.gov/oetcf/kdb/forms/FTSSearchResultPage.cfm?switch=P&id=44637 https://apps.fcc.gov/oetcf/kdb/forms/FTSSearchResultPage.cfm...
      - antoniuschan99 6y ago
        Verification is Declaration of Conformity (DOC)? You can either get a Declaration of Conformity from the lab or just sign it yourself. But in the chance you get audited and it doesn't function how you said it would then you'd get in trouble
        tripletao 6y ago
        Verification and DoC are different (and apply to different types of unintentional radiators), but you're correct that neither involves filing anything with the FCC (or any private body accredited by the FCC; for real most certifications go through a TCB, not directly to the FCC). You just make the file (including any test results required) and keep it in a drawer. The FCC can come and ask for it, and if you don't have it then you're in trouble. ETA: And here's the section about battery-operated digital devices (i.e., unintentional radiators, with no radio transmitter): > § 15.103 Exempted devices. > [...] > (h) Digital devices in which both the highest frequency generated and the highest frequency used are less than 1.705 MHz and which do not operate from the AC power lines or contain provisions for operation while connected to the AC power lines. Digital devices that include, or make provision for the use of, battery eliminators, AC adaptors or battery chargers which permit operation while charging or that connect to the AC power lines indirectly, obtaining their power through another device which is connected to the AC power lines, do not fall under this exemption. And here's the section that makes it fine to build your own stuff in limited quantity, as long as you don't do anything obviously stupid: > § 15.23 Home-built devices. > (a) Equipment authorization is not required for devices that are not marketed, are not constructed from a kit, and are built in quantities of five or less for personal use. > (b) It is recognized that the individual builder of home-built equipment may not possess the means to perform the measurements for determining compliance with the regulations. In this case, the builder is expected to employ good engineering practices to meet the specified technical standards to the greatest extent practicable. The provisions of §15.5 apply to this equipment.