I’m traveling to Eastern Europe on Thursday, and I’m bringing all the usual electronic devices: computer, cameras, phone, Kindle, etc. A number of these devices use USB connections for charging, so rather than using their individual wall warts, I plan to use a powered USB hub. So far, so good.
But I have a few questions. I have a large adapter rated for 240V, 50-1600 watts, and printed right on it it says that it can be used for irons and blow dryers, but not for computers or electronics.
Why not? They only draw a tiny amount of power. What would go wrong?
Also, I have some US-style cube taps that I was thinking I might use to expand the number of outlets available, but all of them are rated for 120 V, not 220. If I’m just using it for low-powered electronic devices will it be okay, or will the 220V melt it and burn my hotel down?
If the latter, are 220V cube taps easily available in downtown Prague?
It doesn’t matter how little the devices draw, the 220V will shove too much power down their corded throats. While on vacation in Ireland, I had a small fan burn out in a few seconds when plugged in to a cheap converter.
I don’t know the electrical specifics, but I think you’ll need a voltage converter in addition to a plug converter.
A mechanical device like a fan definitely needs the right voltage and frequency. But that’s not the same as the electronic devices I’m talking about.
Just to be clear, most of my electronic devices, including the USB hub that I’ll be using to charge the others, have wall warts that accept 240V. So they don’t need voltage converters.
But I was concerned that if I wanted to use a cube tap so I could plug in several at once, the low voltage rating of the cube tap might be a problem, even if I’m only drawing about 1 amp @ 5VDC for each of the devices.
Nearly every modern electronic device like those you have mentioned use a switching power supply which allows AC inputs of 110V/220V and 50Hz/60Hz. Just make sure your USB hub supply has a switching supply (It’ll mention the input voltages and frequencies that it can handle).
So, chances are, you’ll just need a adapter that converts the Czech physical connection to the US standard. You’ll be able to pick it up in Prague or any airport. According to wikipedia, you need a type C adapter.
Your razor and hairdryer are generally just brute force electrical devices and may get fried by the 220V supplies.
edit: Now that I look at your second post, you’ve got the right read on switching supplies. Generally you’ll just have to look at what the current sourcing capabilities of your USB cube ports.
There are two things here. Some of your devices will need a voltage converter as well as a physical plug adapter. Others will just need the physical plug adapter. Unfortunately, folks tend to use the word “adapter” to also mean “voltage converter” so the terminology gets a bit confusing at times.
Is your “large adapter” just a plug adapter or is it a voltage converter as well?
If it is a voltage converter, some of them use clamping circuits instead of wire coil transformers or more sophisticated solid state voltage conversion circuits, just because it is cheaper to do it that way. Some of these output something very close to a square wave instead of a sine wave. This isn’t really a problem for motors and heating devices like a curling iron, but it ends up putting a lot of high frequency noise (due to the square wave) into the power supply which a lot of electronic devices aren’t designed to handle. Depending on the design of your wall warts, you could cause them to over-heat and burn out.
The voltage rating depends on how close the electrical contacts are internally and how much insulation is between them and that sort of thing. No matter how low the current (or even if no current is flowing), the higher than rated voltage could cause an electrical arc, which could result in nasty things like burning down your hotel room.
I can’t imagine that multi-outlet plugs of some sort would be difficult to find over there, but then I’ve never been to Prague. They will be using the standard plug and socket for Prague, though, not a U.S. standard type.
A multi-outlet cube rated for 220V with U.S. style 120 V sockets is going to be very difficult to find, I would think.
Most electronics devices these days like computers and such can handle a voltage input of anywhere from 110 to 240 V with no problem. Don’t assume though. Double check each device. On some of them you may have to flip a switch somewhere, so be careful. I am assuming from your second post that you did double check these, so you should be OK.
A warning about the computer and anything else with a “box on the cable” feed: plug it into the wall first, into the computer second. One of my coworkers managed to fry her computer doing it the other way around. Apparently this has to do with letting the transformer inside the box adapt to the higher voltage, it needs a bit of time (just the time it takes to plug in the other end is enough).
For electronic items with a no-box cable, any transformers are inside. Plug the item and wait a bit before switching it on. I realize the more modern voltage converters need less time but better safe than fried.
Items similar to cube taps are readily available in CZ; not as compact, though. I’ve seen them in the airport and they should also be available in any hardware store.
The European supply is 50Hz while the US one is 60Hz. For simple devices this doesn’t matter much but other things (like synchronous motors) will not like it.
Most travel adaptors are meant for brief use and continuous long-term use should be avoided in favour of a permanent solution. For people moving to a country on a long-term basis it’s usually more cost-effective to buy local versions of your electrical goods.