Are Outlets with USB Ports Safe?

Usb Outlet

In today’s modern world, many new homes have electrical wall outlets with integrated USB ports. You can even find them in commercial areas such as airports, offices, and coffee houses.

Since electrical outlets carry so much power, you may wonder if outlets with USB ports safe to use.

Yes, outlets with USB ports are safe to use. Power output is reduced to 2.4 amps per USB port with 4.8 amps combined output across two USB ports. Some outlets have a lower combined output of 3.6 amps of combined output, which reduces the output in one port to 1.2 amps when both ports are in use.

All USB wall outlets convert the incoming voltage into the standard 5 volts used to power electronic devices, like cellphones and tablets. However, not all outlets provide the same current – some devices only supply 1.2 – 2.4 amps of power.

Outlets with 2 USB ports even share the current between the two ports. Sharing current can reduce the output in half when two devices are plugged in at one time.

USB outlets seem like a hip addition to our home that will offer a lot of conveniences. However, there are essential details that we need to make sure we got covered first.

After looking into the topic and doing some extensive research, I’d like to show you the pros and cons of these new receptacles and whether or not they are worth it.

How Safe Are Wall Outlets with USB Ports?

A lot of the gadgets we have today need a USB port to charge.

There is also a movement towards selling smartphones without chargers. Of course, the idea is to achieve uniformity across all devices, and undoubtedly this will cut down some of production and shipping costs.

Because of this, though, we may find yourselves using things like USB outlets more and more in the future.

So are they a good and safe alternative?

What Is a USB Wall Outlet? USB wall outlets are functioning the same way the standard outlets work.

One of the most significant advantages of having an outlet with USB ports is that you can easily plug in your electrical device (smartphone, tablet, etc.) and recharge its battery without the need to have an adapter. All you need is the USB charging cable that comes with the device.

While you are recharging your electrical gadget using the USB, you can still use the outlet’s plug for devices. So in a way, you can consider this like and variation of a small power strip.

Their purpose is to give our old receptacles more versatility.

USB Wall Sockets and Safety

Although there is nothing bad or wrong with outlets that have USB ports on paper, the reality may not be the same.

The problem is that there is a big difference between cheaper outlets and the more expensive ones. The cheaper (and frequently unbranded) outlets are being more dangerous and unsafe.

Let’s take a look at one investigation carried out by an independent testing laboratory (1). Here is what we can see:

  • All test samples they used failed to meet at least one safety requirement.
  • Some were unbranded.
  • Most of them had no CE markings.
  • Some had no marking about the USB or its amperage. Including no marking as to what electrical devices the USB port is suitable to charge.
  • Most of the outlets had no safety instructions.

How Charging of Electrical Device Works

To better understand the different upsides and downsides, the USB outlets have let’s take a look at their most discerning feature – the USB ports.

The USB ports are there for charging the variety of different electrical gadgets we may have.

So how does that work exactly?

The Battery

Depending on its size, the battery can hold different amounts of charge. The bigger the battery’s capacity, the bigger the charge it can hold, and it will be able to last longer.

However, the actual amount of time the battery can last will depend on the electrical device’s power consumption.

Charging and Fast Charging Basics

Before, it could’ve taken a lot of time to charge a smartphone.

However, with the improvement in technology today, we can enjoy charging our smartphones and tablets much quicker than before. This is another important factor when considering buying a USB outlet.

So not all USB ports are created equal. (2)

  • Standard (and older) chargers supply about 1 amp of electrical current at 5 watts of power.
  • If you are using a newer device with a Quick Charge, these may increase to 2 amps at 10 watts.
  • The latest technology may increase these numbers more, reaching at least 2.5 amps at up to 18 watts.

USB Outlets Charging Basics

Not everybody has the newest top of the line smartphone. And some of the older phones have a certain limitation when it comes to charging. Older models may be able to take a maximum of 1 amp while charging.

Let’s go back to the testing done by an independent lab. We can see that most of the USB outlets were within range volt-wise (being within 4.75 to 5.25 V DC).

The thing that is concerning is that the majority (eight out of the nine tested outlets) failed to stay within the 1500 mA of current output.

Half of them were supplying more or less electrical current.

One outlet was labeled to have an output of 2100 mA while, in reality, it was supplying 2600 mA.

Fast Charging and More

To take full advantage of the fast charging most modern devices offer, they need to draw the corresponding electrical current that will allow for fast charging to happen.

However, for this to happen, a USB 3.0 or 3.1 may frequently be needed.

  • USB 1.2 and 2.2 are capable of delivering up to 0.5 A.
  • USB 3.0 can go up to 0.9 A, and dedicated chargers can even go to 1.5 A
  • USB 3.1 can go up to 1.5 A or even 3 A.

So depending on the type of USB port found on the outlet, you may find yourself severely limited as to how quickly you may be charging your mobile phone.

Also, older phones may require an older type of USB outlet to charge correctly. So you may be facing some compatibility issues now or in the future.

Future Improvements

The technology behind USB ports has constantly been improving for the past several years, and it doesn’t look like it will stop anytime soon.

A notable downside is that the USB port on the outlet may become outdated way sooner than expected.

Is Installing a USB Outlet Really Worth It?

Installing a USB outlet may not seem like a good idea. Especially after considering the different kinds of failing, they are prone to have.

The way USB charging technology has constantly been evolving. At first, we had a standard USB port. But then, with time, things changed. Now we even have USB 3.0, 3.1, USB type C, mini-USB, and more.

An outlet with a standard USB, although useful, may be outdated in a few years, if even that.

On the other hand, electrical outlets can last for several decades. So while your outlet may still work as intended, the USB port may be outdated and not useful in any way before the actual outlet breaks down.

Another case in point is that the standard (branded) outlets are tough devices that offer safety and are reliable. In comparison, USBs are considered to be less reliable.

Also, there are other inconveniences. While USB outlets can be retrofitted and used in older homes, they may prove much thicker than the standard types of outlets. And they may not fit easily in the same place a standard outlet may fit. You may also need electrical wiring upgrades or an electrical panel replacement if you intend to install a USB outlet in place of 2-prong ungrounded outlets.

What Are the Alternative to USB Outlets?

Seeing how some of the outlets may be either unsafe or just inconvenient may be a dealbreaker for many people.

However, there is an alternative if you are in a situation where you just need the extra USB charging ports.

This alternative comes in the face of Multiple USB Charger, 60W/12A 8-Port Desktop Charger Charging Station Multi Port Travel Fast Wall Charger Hub. These are like USB power strips.

Even in terms of safety, these are better.

They can be extremely useful if you need to charge several different electrical gadgets at once. They come with a various number of USB ports from 2 to 10 and more. All you will need is some USB cables if you don’t already have them.

They can be conveniently installed in your office, bedroom, kitchen countertop, or family room.

Final thoughts, plugging USB devices into overloaded outlets can cause the outlet to overheat. If the house has AFCI protection, it can cause the AFCI nuisance tripping. Overloaded circuits without AFCI protection can cause a fire.


Hubert Miles | Licensed Home Inspector, CMI, CPI

Hubert Miles is a licensed home inspector (RBI# 2556) with more than two decades of experience in inspection and construction. Since 2008, he has been serving South Carolina through his company, Patriot Home Inspections LLC. As a Certified Master Inspector, Hubert is dedicated to providing his expertise in home inspections, repairs, maintenance, and DIY projects.