You’re essentially asking whether it’s safe to charge after charging has already begun. That’s like asking, “May I come in?” once you’re already sitting on the sofa 😄
Yes, it’s safe to continue charging as long as you don’t see any warning or alert. Just make sure you’re using an Apple-supplied cable or a certified MFi cable—because charging is fine, but charging with sketchy cables is how horror stories are born.
Search for accessories that have completed MFi certification. Once an accessory has completed MFi certification requirements and is reported to Apple as sold/distributed, it will be searchable in our public database of authorized Lightning, headset, charging, iAP-enabled, and Find My network-enabled accessories.
Learn how to identify counterfeit or uncertified Lightning-based accessories.

Follow these steps:
- Remove any debris from the charging port on the bottom of your device.
- Restart your iPhone or iPod touch.
- Try a different USB cable or charger.
- Make sure you have the latest version of iOS.
If your iPhone or iPod touch won't charge - Apple Support (IN)