When do I start having to worry about regulatory issues if I sell a product that boosts DC to DC voltages in the 80-100 volt DC range (.5 to 3 amp range)

How safe is 48V DC? is the closest i came on a search. Any help with good search terms? It seems 50 volts is the magic number..

What Regulatory Requirements are Really Necessary for Sale in the USA?

  • \$\begingroup\$ For the US? The main regulatory requirement is FCC, which has nothing to do with how much power the device consumes or what voltage it operates at. Safety requirements (UL or other NRTL) are not a regulatory requirement, as the answers to the question you linked to say. \$\endgroup\$
    – The Photon
    Commented Jan 3, 2019 at 3:36
  • \$\begingroup\$ As a practical matter, 80-100VDC is high enough to give you a bad shock. So there is that. \$\endgroup\$
    – user57037
    Commented Jan 3, 2019 at 5:09
  • \$\begingroup\$ To ensure saleability in every city in America , it is best to be listed. mikeholt.com/mojonewsarchive/EES-HTML/HTML/… \$\endgroup\$ Commented Jan 3, 2019 at 6:13

2 Answers 2


For the US this is mostly handled by UL standards.

There are a bunch of standards to read and unfortunately you have to purchase them.

Here is a few to get started:

Then it depends of your product, what is the intended use for which market and specific norms may apply, it is not the same for household, fab or laboratory equipment for instance.

If the voltage goes above 50VDC, then the standards are more restrictive, it depends if you have conductive or plastic casing, you might need double insulation.

  • \$\begingroup\$ Thanks. That's plenty to go on. Making a usb-c to 84 volt boost to charge personal electric bikes/ scooters. \$\endgroup\$ Commented Jan 3, 2019 at 5:21

Your question is not clear about what you mean by "worry", or "magic number"...

If you are asking about the design rules necessary for safety certifications - UL, CSA, TUV, etc. - then now. The requirements vary widely depending on the type of equipment and its construction, and the "kind" of voltage. Below is a snippet from a UL web page. It is completely out of context, and presented only to show the intricacies of the certifications universe and why specific questions are better for a discussion.

Table 8 of, specifies limits for pulses less than 3 seconds; and for a pulse of 3 seconds or longer, it directs the reader to sub-clause for voltage and current limits. While a voltage limit of 42.4 Vp is stated, it should be understood that for repetitive pulses less than 3 seconds, this table content is an abridged version of Table 4 of sub-clause which includes 60 Vdc and 30 Vrms for ES1; and should also be used.

  • \$\begingroup\$ how are 60VDC and 30Vrms equivalent, and not 60VDC and 60Vrms, or 85Vpk? This is something that has always confused me... \$\endgroup\$
    – jrive
    Commented Aug 22, 2023 at 16:07

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