I doubt they are any worse than the average cheapo USB power supply, but I doubt they are any better. That is, they provide only coincidental surge protection.

Even the retail surge protectors most people buy can be ineffective if your area has a dirty power feed or frequent lightning strikes.

The Amazon photo suggests this socket provides 2.1 amps, which I think is a bit hotter than many USB sources. Perhaps one of the experts can weigh in on that, and whether the old adage that a slower charge at a lower rate is better for battery life than a quick charge at a higher rate.

I LOVE mine! I paired it with some phone holders and it works great.

The 2.1 amp rating, while not clarified in the specs, usually is a combination of the total of the two USB connectors, which may be often be asymmetric - .5 amp on one, and 1.6 amp on the other.

You need to look at the charge requirements of the devices you are plugging in to the USB charge ports. A cellphone can charge off a low current supply but a tablet requires a much higher current availability to charge as quickly.

The device connected to the USB port determines it's rate of charge, regulates it, and is only limited by the supply current available to it - the available current is only a "limiting factor" and it does not force the charge rate to be any faster.

Part of all this conundrum is that the USB port was never designed to serve as a "charge source" but to just to simply supply current to slave devices connected to the USB port. But then manufacturers soon found they could eliminate the cost of a wall-wart transformer by making it "USB rechargeable".

You might also want to look at the "plug in" type devices that provide a feed-thru for AC and USB ports for charging - being external they can often provide better heat sinks and current availabilities.

yosemitebill-
Thanks...that was a great explanation. I did check with Cooper Wiring tech support today, and they confirmed that the 2.1 amps is a total for the two USB ports. I also talked with Apple today about my iPad requirements, and it would be better to use the wall wart because it will deliver faster charging and at an amperage greater than 2.1. I may still be interested in installing one of these, but would mainly use it for phones and other lower demand devices.

One other thing: Can you clarify in more detail what type of plugin devices you were referring to at the end of your post?

There's a number of plug-in adapters that kind of look like those six-in-one blocks that just plug into an existing receptacle. They usually offer one or two AC receptacles and a couple USB outlets.

Thanks...now I know what you mean.

I went with the Leviton version. Pretty similar with a total of 2.1 amps. It's used for Android phones, Iphones and Ipads without any issues. I prefer the receptacles with the built in USB as it reduces the wall warts.I have a multi adapter USB cable with reduces the cables to a couple.

The Leviton version reduces it to as single 120 outlet but that has no impact in my situation.

http://www.amazon.com/gp/product/B008O11IEY

Here is a link that might be useful: Leviton T5630-W 2.1-Amp High Speed USB Charger/Tamper-Resistant Receptacle

diane-
That's the other one I thought looked good, too.

HD also has a plug-in outlet adaptor that looks like an outlet with cover, though 1" thick. Cost about $12. (I did not see it on the website, but just bought one in the store.) Looks like the one on this link:

Here is a link that might be useful: USB adaptor

This post was edited by homebound on Mon, Jun 24, 13 at 9:15

Does anyone know how much power these devices draw when nothing is plugged in?

"Does anyone know how much power these devices draw when nothing is plugged in?"

Most component reference designs I'm familiar with (used in building products like these) typically try to limit idle current to less than 100 milliwatts. And, there is an actual effort to reduce that even further since it is often used as "bragging rights" in the data sheets.