How Power the Arduino Uno

Arduino Uno pin out - Power Supply

There are 3 ways to power the Arduino Uno:

Barrel Jack - The Barrel jack, or DC Power Jack can be used to power your Arduino board. The barrel jack is usually connected to a wall adapter. The board can be powered by 5-20 volts but the manufacturer recommends to keep it between 7-12 volts. Above 12 volts, the regulators might overheat, and below 7 volts, might not suffice.

VIN Pin - This pin is used to power the Arduino Uno board using an external power source. The voltage should be within the range mentioned above.

USB cable  - when connected to the computer, provides 5 volts at 500mA.

+5V pin

Here's a less formal way to look at it: Providing power directly to the +5V pin is (almost) exactly what happens when the Uno is powered over USB. As USB power is perfectly fine, by design, then your setup should be OK too.

External regulated +5V can be supplied to the USBVCC net just as well, for example by using an USB-B cable.