How to Install a USB Outlet (Replace a Standard Outlet in 30 Minutes)

Frequently Asked Questions

What is a USB outlet and how does it work?

A USB outlet (also called a USB receptacle or combo outlet) replaces a standard 15- or 20-amp wall outlet. It has the usual two or three 120V AC plug slots plus built-in USB-A or USB-C charging ports on the face of the outlet. The outlet contains a small power converter that steps down 120V AC to the 5V DC that USB devices need. You get dedicated USB charging without occupying an AC slot with a charger brick.

Do I need an electrician to install a USB outlet?

No — replacing an existing outlet with a USB outlet is a straightforward DIY project. You're swapping one device in the same electrical box with the same wiring. No new wiring, no panel work. The only skills required: turning off the correct breaker, using a voltage tester to confirm power is off, and connecting three wires (black, white, bare copper or green) to the correct terminals. Most homeowners complete the swap in 20–30 minutes per outlet.

Will a USB outlet fit in my existing electrical box?

USB outlets are slightly deeper than standard outlets because of the built-in USB charging circuitry. Most fit standard single-gang electrical boxes. However, if your box is an older shallow box (less than 2 inches deep) or is already crowded with wires, you may find it tight. Before buying, measure the depth of your box. If it's shallow, look for a USB outlet with a slimmer profile or consider using an outlet extender.

How many watts can a USB outlet charge at?

It varies by model. Basic USB-A outlets typically deliver 2.4A per port (12W), which is adequate for smartphones but slow for tablets. Look for outlets with USB-C Power Delivery (PD) or Quick Charge (QC) support if you want to fast-charge newer phones or charge a tablet at full speed. USB-C PD outlets can deliver 18W–45W depending on the model. Check the spec sheet before buying if fast charging matters.

Can I install a USB outlet on a 20-amp circuit?

Yes, but you need to buy a 20-amp rated USB outlet (the face will have a T-shaped neutral slot rather than a straight slot). Using a 15-amp outlet on a 20-amp circuit is against code. The USB charging portion of the outlet is the same regardless of the AC amperage rating — the difference is the capacity of the AC receptacle portion.

What if my outlet box has only two wires (no ground)?

Older homes wired before the mid-1960s often have only hot and neutral wires — no ground wire. In this case, you cannot use a standard grounded outlet. You have two code-compliant options: install a GFCI outlet (which provides shock protection without a ground wire) and label it 'No Equipment Ground,' or run a new grounded circuit. Most USB outlets require a ground wire for proper operation — check the product specs before purchasing for ungrounded boxes.

Installing a USB outlet: (1) Turn off the breaker for that outlet. Verify with a voltage tester.

USB outlets are one of the most practical electrical upgrades a homeowner can make. Charging cables are everywhere. Outlet adapters are bulky and block adjacent plug slots. A combo USB outlet solves both problems — dedicated USB ports that don’t occupy AC receptacle space, permanently installed at any outlet where you regularly charge devices.

The installation is nearly identical to replacing a standard outlet. If you’ve done that before, you’re already 80% of the way there. If you haven’t, this guide walks through every step.

What You Need

Gather these tools and materials before you begin:

• USB outlet with USB-A and USB-C ports — pick a reputable brand with UL listing
• Non-contact voltage tester — essential safety tool, confirms power is off
• Outlet tester / plug-in circuit tester — verifies correct wiring after installation
• Insulated screwdrivers (flathead and Phillips) — for terminal screws and cover plate
• Needle-nose pliers — for forming wire hooks at terminal screws
• Wire stripper — in case existing wire ends need refreshing

Choose the Right USB Outlet

Before buying, decide on these specs:

Amperage rating. Most home circuits are 15-amp (14-gauge wire). Bedroom, living room, and general-use outlets are typically 15-amp. Kitchen and bathroom circuits are usually 20-amp (12-gauge wire, T-shaped neutral slot on the outlet face). Match the outlet amperage to the circuit. When in doubt, check the breaker label or look at the existing outlet — if the neutral slot is T-shaped, it’s a 20-amp circuit.

USB port types. USB-A only outlets are cheaper but limited. USB-C outlets support Power Delivery for fast-charging newer devices. USB-A + USB-C combo outlets are the most versatile and best value for most locations.

Total charging wattage. The combined USB wattage is usually between 18W and 45W depending on the model. Higher is better if you’re charging two devices simultaneously or need fast-charge speeds.

Tamper resistant. Required by code in most areas for new installations. Look for “TR” in the model name. Worth getting even if your jurisdiction doesn’t require it.

Step 1: Turn Off the Circuit and Verify Power Is Off

Go to your electrical panel and turn off the breaker for the circuit you’re working on. If your panel isn’t labeled, plug a lamp or phone charger into the outlet and flip breakers until it goes dark.

Return to the outlet with a non-contact voltage tester. Hold the tip near each slot of the outlet — both the wide neutral slot and the narrow hot slot. The tester should show no voltage. Test the outlet below it as well if it’s a duplex (double outlet), since both outlets share the same circuit.

Do not proceed until the tester confirms no voltage. This step is non-negotiable.

Step 2: Remove the Old Outlet

Remove the cover plate screw (center of the cover plate) and set the plate aside. Unscrew the two mounting screws holding the outlet to the electrical box — one at the top, one at the bottom. Pull the outlet gently out from the box. There will be 2–4 inches of slack in the wires.

Take a photo of the wiring before disconnecting anything. You want a reference showing which wire color is on which screw terminal.

If wires are attached with terminal screws: Loosen each screw with a flathead screwdriver and unwrap the wire from the terminal. Three wires typically present: black (hot) on the brass screw, white (neutral) on the silver screw, and bare copper or green (ground) on the green screw.

If wires are inserted into back-stab (push-in) terminals: Insert a small flathead screwdriver into the release slot next to the wire insertion hole to release the wire. Back-stab connections are less reliable than screw terminals — when you install the new outlet, use the screw terminals rather than the push-in holes.

Step 3: Inspect the Wiring

With the old outlet removed, take a moment to inspect the wires:

• Look for any discoloration, melting, or burn marks on the wire insulation — signs of a previous overload or arc. If you see this, have an electrician evaluate before proceeding.
• Check that wire ends have clean copper with 3/4 inch of insulation stripped. If the copper is dark or corroded, clip the end and re-strip with a wire stripper to expose fresh copper.
• Count the wires. If there are two black wires and two white wires plus a ground, your outlet is in the middle of a circuit (power comes in, passes through to the next outlet). Connect both black wires to the brass terminals and both white wires to the silver terminals — the USB outlet handles this the same way a standard outlet does.

Step 4: Connect the Wires to the New USB Outlet

USB outlets use standard screw terminals. The labeling is the same as a regular outlet: brass screws for hot (black), silver screws for neutral (white), green screw for ground (bare copper or green).

Form wire hooks. Use needle-nose pliers to bend the stripped wire end into a hook (J-shape). Wrap the hook clockwise around the terminal screw. Tightening the screw then closes the hook around it — if wrapped counterclockwise, the screw tightening would push the wire off.

Connect ground first (green screw), then neutral (silver screw), then hot (brass screw).

Tighten each terminal screw firmly — wires should not pull out under hand pressure. Loose connections cause overheating.

Check the USB outlet’s instructions. Some brands have slightly different terminal layouts or include wire guides. Spend 60 seconds reading the included sheet before connecting.

Step 5: Fold Wires and Mount the Outlet

With all three wires connected, carefully fold the wires accordion-style back into the electrical box. USB outlets are slightly deeper than standard outlets, so pack the wires neatly to avoid pinching.

Guide the outlet into the box. The outlet must sit flush — if it’s cocked to one side, the cover plate won’t sit flat. Align it so the USB ports are oriented correctly (typically facing up or as desired).

Thread the mounting screws into the box’s mounting ears (top and bottom). Tighten them alternately, a little at a time, until the outlet is snug and level. Do not overtighten — you’ll crack the outlet housing.

Install the cover plate. Most USB outlets come with their own cover plate that accommodates the wider USB port section. Use the included cover plate screw.

Step 6: Restore Power and Test

Return to the panel and turn the breaker back on.

Test the AC outlets first. Plug in a lamp or phone charger and confirm power. Better yet, use a plug-in outlet tester — it shows whether the hot, neutral, and ground connections are correct. A “correct wiring” reading means you’re good to go.

Test the USB ports. Plug in a USB cable and connect a phone or tablet. Confirm it begins charging. If you have a USB-C port with Power Delivery, try a USB-C device that supports fast charging and verify the charging speed matches the outlet’s rated output.

Test the second AC slot if the outlet is a duplex (two AC receptacles).

If the outlet tester shows a wiring fault, turn off the breaker immediately and recheck your connections — most commonly a hot and neutral wire swapped, or a loose connection.

Locations That Benefit Most from USB Outlets

Not every outlet in your home needs a USB upgrade — prioritize high-charging locations:

Bedside nightstands. The highest-value location in most homes. Charging phones overnight, no adapter needed.

Kitchen counter outlets. Great for charging devices while cooking. Look for outlets with higher wattage USB-C ports for tablets.

Home office desk outlets. Reduces adapter clutter at workstations.

Bathroom outlets. Check that the existing outlet is GFCI-protected before replacing. Buy a combo GFCI + USB outlet for bathroom use — these are available and code-compliant.

Living room entertainment area. Useful for charging remotes, headphones, and game controllers.

When to Call an Electrician

Most USB outlet swaps are solidly within DIY range, but call a licensed electrician if:

• You find burn marks, melted wire insulation, or a burning smell when you open the box
• The wiring in the box is aluminum (silver-colored, not copper-colored) — aluminum wiring requires anti-oxidant compound and special outlets
• Your box has only two wires and no ground — the fix requires a GFCI outlet or running new wire
• The box is too shallow or too crowded to safely house a USB outlet

Related Reading

• How to Replace an Electrical Outlet
• How to Install a GFCI Outlet
• How to Install Under-Cabinet Lighting
• How to Add an Electrical Outlet — add a new outlet where none currently exists