Symbols on DC power supplies? Square inside a square?

[Jurgeaustin]

Hello,
We can find a symbol of a square inside another square and I have seen it on several DC Power Supplies and cannot figure out what it means. I want to know whether it is an international symbol from the FCC.

Thanks

[lordsmurf]

The FCC is the federal communications commission, and only applies to the United States.
Beyond that, the FCC only regulates communication technology, and will not really be found in relation to power supplies.

Can you attach a sample image of this logo to the forum?

[kpmedia]

By coincidence, I was just now throwing away a dead power adapter from a D-Link gigabit network switch, and noticed what appeared to be square inside of another square amongst the grouping of logos! Attached are images.

And like you, I have absolutely no idea what that logo means.


squarelogo-dlinkswitch.jpg

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The label is very, very tiny -- smaller than a quarter (USD 25-cent coin).
I took these with my tripod-mounted Nikon D3s in the studio real quick. I couldn't read it even with a handheld magnifying glass.

[NJRoadfan]

The power brick for my Canon camcorder has the double box on it with the text "DOUBLE INSULATED" next to it. A quick search confirmed that is what the symbol indicates, specifically that it is a "Class II" device.

http://en.wikipedia.org/wiki/Appliance_classes

[kpmedia]

Thanks.

Quote:

A Class II or double insulated electrical appliance is one which has been designed in such a way that it does not require a safety connection to electrical earth (ground).

The basic requirement is that no single failure can result in dangerous voltage becoming exposed so that it might cause an electric shock and that this is achieved without relying on an earthed metal casing. This is usually achieved at least in part by having two layers of insulating material surrounding live parts or by using reinforced insulation.

In Europe, a double insulated appliance must be labelled Class II, double insulated, or bear the double insulation symbol (a square inside another square).

See also: Double switching