Very likely possible 10mm, but haven't seen many or too detailed descriptions when was looking for safes and was no electrical outlets or pass throughs noticed on ones seen when personally viewing them. But, has been awhile and things available in different locations can change? Another thought is if or when power goes out, what then? Or, is an electrical outlet near by? If supplied cord is only 6' long, extension cords can easily be trip hazards. Could likely install an outlet in safe or wall, but how many people are capable of that? Not thinking everyone is. Is what was pointing towards with previous comment.
Am not trying to beat on product or idea, but not everyone or every safe has an electrical outlet or a pass through. Maybe a good reason for that for several reasons? Possible insect or moisture intrusion? Product and idea is likely a good one if it's usable for certain applications. There are certain requirements needed with safes and other products, they're not all compatible or easily compatible.