Strange symbol on PSU label

I have a PSU (wall wart) with a symbol on the label that I don't recognise. I'm curious as to what it means. It's probably some safety symbol of some form, but not one I have ever seen before. I'm sure it's obvious though:

It's printed on the label with all the other safety symbols, ratings, etc.

Underneath it, I don't know if it's related to the symbol or not, is an ambient temperature rating of ta=40°C and an IP rating of IP20.

If you're interested, here's the entire label, so you can see it in context (and yes, I know those current ratings are completely wrong - 0.5A in, 0.5A out?!?!):

Any clues?

• I'll go with switching for 500 Alex.... – Trevor_G Mar 23 '17 at 15:03
• You mean to indicate an SMPS? Could be, though I've never seen it on any of the other SMPS wall warts I have... – Majenko Mar 23 '17 at 15:04
• The symbol caught my eye because it is so component-like. – Majenko Mar 23 '17 at 15:12
• Looking through the catalog of IEC symbols the other mystery one is "Safety isolating transformer, shortcircuit proof" - 5947 (or I think so, all I have is a preview, and there happens to be a "click here to buy" banner right over that bit). – Majenko Mar 23 '17 at 15:33
• Yes, found a better copy: iso.org/obp/ui#iec:grs:60417:5947 – Majenko Mar 23 '17 at 15:36

This is an SMPS symbol from the IEC 60417 standard. It identifies an

electronic device incorporating transformer(s) and electronic circuitry(ies), that converts electrical power into single or multiple power outputs.

There's also a similar symbol for a linear PSU:

The PSU must have an internal operating frequency below 500 Hz to be considered linear by the standard.

• That's a rather interesting standard there - have to keep that in mind next time I'm designing a thing. – Arsenal Mar 23 '17 at 15:37

Power supply unit, switch mode.

ISO Standard Reference No : 6190 Registration date : 2013-10-19

Status : Active

Standard :

IEC 60417 — Graphical Symbols for Use on Equipment

Committee :

IEC/SC 3C

ICS :

https://www.iso.org/obp/ui#iec:grs:60417:6190

• Frankly, one thing is missing in the answer: what is that symbol?! – Gregory Kornblum Mar 23 '17 at 15:32