WiremanWireman · USB or smart receptacle not working: troubleshooting for electricians · 2023 NEC ·
USB or smart receptacle not working
Separate the receptacle’s power from its electronics: USB ports, Wi-Fi, app control and schedules.
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How it works
A USB receptacle has a small power supply inside that turns 120 V AC into 5 V DC, and USB-C ports may negotiate higher voltages for fast charging. A smart receptacle has a radio, a tiny power supply and a relay that switches the outlet. Both depend on electronics that can fail on their own while the plain receptacle part is fine, and both have output limits printed on the device.
Every question and answer in this guide. Tap “Step by step” to walk through it.
- What kind of receptacle is it?
- USB portsPlug a lamp into the regular outlet on it. Does it work?
- Outlet works, USB doesn’tTest: Try another cable and device
- Works with another cable or deviceA bad cable or device
- No USB power with anythingThe USB power supply has failed
- Both are deadNo power to the receptacle
- Both work, but charging is slowThe USB output is lower than the device wants
- Outlet works, USB doesn’tTest: Try another cable and device
- Smart (Wi-Fi or app controlled)Press the button on the device itself. Does the outlet turn on?
- Yes, but the app can’t control itDoes the app show it as offline?
- OfflineLost Wi-Fi connection
- Online but won’t switchA device or app glitch
- No, the button does nothingTest: Check for power at the deviceExpect: About 120 V.
- About 0 VNo power to the receptacle
- 120 V, but the device is deadThe smart receptacle has failed
- Wires loose or on the wrong terminalsWired wrong or loose
- It turns on or off by itselfA schedule, automation or power-loss setting
- Yes, but the app can’t control itDoes the app show it as offline?
- USB portsPlug a lamp into the regular outlet on it. Does it work?