Using a grounded 3 pronged US plug in spain and italy and prague?

So if your U.S. plug requires a grounded outlet, you'd ideally want a grounded adapter plug, but you might not find grounded outlets in Spain, Italy, and the Czech Republic, and may just have to use an adapter that accepts your 3 U.S. prongs on the front and has 2 round pins on the back. What appliance(s) are you bringing with a 3-prong cord?

To begin with, I'm assuming you've checked the Input Voltage requirements on the device to ensure that it will operate on 220 VAC electrical systems? The Plug Adaptor will be the least of your worries if it's only designed for 110 VAC.

Although it is possible to use three pin plugs with two pin Euro Adapters, as the appliance is provided with a grounded plug it would be best to use a grounding Plug Adaptor. The grounding pin was put there for a reason, and is likely part of the electrical safety features.

The grounding adaptor for Italy is unique to that country and looks like this.

The grounding adaptor for Spain looks like this. This model accommodates both the "grounding ears" and the protruding ground pin, so is fairly universal. The same model should work in the Czech Republic.

It's also a good idea to pack along a couple of two-pin Euro Adaptors.

My Chromebook computer power unit has a three conductor North American grounded input plug. My Rick Steves Euro (Type C) adaptor is shaped to allow the round ground pin to bypass the body of the adapter and fit typical Euro sockets. My power unit's input is 100 - 240 volts 50/60 Hz and outputs 19 volts @ 2.37 amps. As long as the power unit with non-nonmetallic housing is not damaged, the absence of grounding doesn't seem to be a high risk.

Spain uses the German Schuko receptacle which will work this this adapter. Czechia uses the French style Schuko receptacles, which will also work that adapter. Modern construction in Italy uses the German Schuko receptacle along with the three hole grounded Italian receptacle. The two-pin Europlug will work in the Italian receptacle, but some safety feature will be lost.