Safety precautions when making a commercial electronic product

Question

I have designed and fabricated an electronic device. High level explanation for this device is as follows:

The device designed scans the environment for RFID tags and when a tag gets too close to the scanner it triggers and alarm and then sends out an SMS using the SIM800l module.

The device pulls at most 2.5A and is connected to 5V supply. The scanner device takes 5V while the SIM800l takes 3.8V. Therefore a buck converter was used to step down the voltage from 5V to 3.8V.

The power supply contains a variety of safety features such as Short circuit / Overload / Over voltage. The main supply also has a surge protector. Hence the plug outlet and therefore my device is safe from any sort of surges.

The scanner is connected to the SIM800l using Veroboard and some resistors. These resistors are used as a voltage converter. The scanner output 5V but the SIM800l needs 3.3V.

The entire project is encapsulated in a plastic housing. The circuitry (scanner and SIM800l) does not produce a lot of heat, in fact, it does not even feel warm after 14 days of testing continuously.

My question is therefore what else saftey measures should I employ if I want to take this product commercially?

Answer 1

This device is an intentional radiator (it transmits RF) so it will be relatively expensive to get it certified for all jurisdictions. Safety is on top of that.

Your product may be otherwise well designed with what you think are good protections, but if a single-point failure can cause a fire or electrical shock then it may need to be modified. If every part that comes near the mains is plastered with listings and your design is decent it will be a lot easier/faster/cheaper. They don't care so much if your product is reliable or useful, the focus is solely on whether it can cause harm in one of a number of ways. For example, the plastic housing may need to be made of an appropriate resin with fire retardant additives to be approved, but certain fire retardant additives are banned in some jurisdictions.

So maybe decide where you want to try selling it and research which standards apply (often there are gray areas) and get ahold of copies of the relevant standards.

Answer 2

External Power

As I understand the design, you are using mains AC power (presumably 120V - 240V) to power a device with the power being converted using a module inside your device. That means you will need to pass some appropriately severe design rules and testing to protect both human safety (i.e., prevent shock from exposed mains wiring) and fire (higher voltage present = higher risk, including heat dissipation from the power converter).

Since your primary voltage is 5V DC, you should seriously consider use a "wall wart" to provide the 5V DC power. Those are readily available, already tested for safety by UL and other organizations, and very inexpensive. You may be able to use a USB charger - those are incredibly common - but you need to make sure that it can provide sufficient current to meet your needs.

Once you switch to an external power supply, the safety concerns are substantially reduced. You still have heat == fire concerns, but without any 120V (or higher) AC present in your box, electrical safety is pretty much resolved. 5V @ 3A just can't do that much damage. 120V at a tiny fraction of an A can kill.

As noted by others, there are a number of other factors besides electrical safety, potentially including:

• Hazardous Materials - Not likely to be a factor here, except that you'll almost certainly end up with a California 65 Warning if you decide to sell this across the US including California. I'm not sure what, if anything does not get a California 65 Warning.
• Radio Frequency Interference - FCC in the US, other agencies elsewhere. Anything which can emit radio frequency signals, which includes almost anything electronic but by definition anything with a WiFi or cellular or Bluetooth transmitter, will typically require some level of certification that it follows certain guidelines to prevent interference.

Answer 3

Unless you plan to fund your entire venture on your own, I think this effort is somewhat misplaced. It's not where you need to be putting your effort or money right now to bring this to market.

Bringing the product to code or to standard should certainly be part of your business plan, but you should run with the assumption that this product can be brought to code by a person with the appropriate skill set. Your focus should probably be on a prototype that is sufficient to gather enough support to move it along to the "next step" (venture capital, angels, business loan, sell it or license it to a company in the arena), and potentially protecting IP.
That "next step" might well include code compliance, but it sounds like you're at too early a stage to merit attention to that area (though keep it in the back of your mind!). We call such an effort a "Minimum Viable Prototype"

Lastly, if you don't have a business plan, you should have a business plan. If the risk of a false start because of code noncompliance would be really troublesome (i.e., if it's of tremendous importance to get this right), then handling this from a position of inexperience is likely too risky, and your plan should include a consultant in the area.

Answer 4

the minimum safety requirements for your type of equipment, that apply in Europe and most parts of the world are covered by the IEC 62368-1 standard "Audio/video, information and communication technology equipment. Safety requirements" (previously it was the IEC 60950-1). This will be what the certification for electrical safety will be based on for assesing your equipment.

Answer 5

Hire someone experienced to get it through listing

That is, UL listing and FCC cert, as well as CE, RoHS etc. This is a very difficult area fraught with tricks and traps for the inexperienced. They’re not trying to fool people; they just haven’t done a very good job making the process accessible to hobby builders. You cannot solo this; those who have tried have been eaten by the system.

Keep in mind a big part of it is your factory manufacturing the items. You need a factory the listing agency has a relationship with. Random Chinese factory, or even random American one, may not be up to snuff. That’s especially true if your factory generally does limited run stuff e.g. for industrial controls, and doesn’t do consumer products.

It works better if your expert is in the loop starting early

A lot of people think this compliance is a last-minute bolt-on; one of the boxes you tick right before production.

That’s not the best idea, especially when you’re dealing with RF. You are better off having the Code requirements inform your design choices from the moment your idea hits the back of the napkin.

Watch what your competitors are doing

A lot of people see their competitors swerve out of their way to take a particular approach. They think “Well that is weak, I can do better than that!”

Then, as you get into the process, you find out there’s a reason they took that approach. The reason relates to the product safety standards or Code requirements everyone must follow.

For instance there’s a little detail that UL must approve both your device and its installation instructions. Home power monitoring systems like Sense place their “box”, its power supply and all the current transformers entirely inside the service panel, with nothing but a WiFi antenna sticking out. Any half-competent EE can get the idea to mount the box externally with an atttractive, interactive display, and just run the CT pigtails into the panel. But that cannot be installed legally, so UL will never approve it.

UL needs electrical equipment to meet published safety standards (the UL White Book). But UL also approves the labeling and instructions as part of the UL Listing (which is why some instructions are so ghastly; they used tired and true boilerplate text). UL needs to see that the installation procedure is compatible with the Electrical Codes (CEC for Canada and El NEC for most of the rest of North America, for instance). Your instructions can't tell people to violate Code.

Answer 6

Again, if you are alone in your venture, you need to make sure you are immune to false positives, since you will most likely be required by FCC to accept external interference. Code acceptance won't include this. if you are cheapest on the market, but don't work as is expected...