Hello David, IEC 62368-1 bases flame ratings on a number of factors. One of them is the available power. Each circuit is rated by the available power under worst-case conditions. A power source that can supply no more than 15 W under those conditions is PS1. Between 15 - 100 W is PS2 and over 100 W is PS3. This is a simplification, but it gives the general idea. The requirement for the flame rated plastics is based on the lighter outlet being PS2 or higher.
Again, this is a bit of a simplification, but a PS1 circuit is considered low enough energy that a fault isn't likely to cause ignition. A PS2 circuit has enough energy to cause ignition of flammable materials, but not so high of energy that it could cause a significant fire. A PS3 circuit is considered to be capable of igniting and sustaining a larger fire and it has stricter requirements for flammability of materials and fire enclosure design. We can even look at it in a historical perspective. Few cars now ship with a cigarette lighter. The outlet is just an auxiliary 12 V power port. However, it was originally designed as a cigarette lighter, so it needs to provide enough power to heat the lighter to the point where it will cause ignition of the cigarette. Based on that, it should be obvious that there is enough power to cause ignition. Ted Eckert The opinions expressed are my own and do not necessarily reflect those of my employer or TC 108. From: David Huff <[email protected]> Sent: Monday, March 15, 2021 2:35 PM To: [email protected] Subject: [EXTERNAL] [PSES] Question on 12V accessory outlet and IEC 62368-1 All, I am working on a charging device which will be plugged into a 12V accessory outlet (cigarette lighter outlet) I am trying to get it qualified to IEC62368-1:2018. (the device it charges is falling under IEC62368-1) The reviewer is insisting that my cigarette lighter plug must be UL94 flame rated to V1. Most of the cables I see out there are HB rated, and VW-1 cords. This IEC standard is new to me, but appears more geared to devices with higher voltage cords than a 12V DC source. Am I missing something, or is it overkill for that high of a flame rating for a 12V device? Any supporting documents or ideas are welcome here. I am also finding most companies have no idea of the flame rating of components like these items. Thanks, David - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. 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