Ok read this in another post....
Based on some quick searching, I believe that Alaska adopted the NEC 2008 edition as of June this year; which is bad news for your installation in terms of code-compliance. However I should note that your installation would have been allowed under the NEC 2005. So the question about safety is one of tiny percentages (allowed in May, not in June). Compliance with '08 code does provide a somewhat safer installation, but as-is yours certainly is not unsafe. Since there seems to be no code enforcement in your locality it's up to you.
I'll touch on the important points between '05 code and '08 code:
#2 aluminum used to be allowed for 100A subpanels under an interpreted wording of a code article. They have now explicitly changed the wording so that #2 aluminum is good for 90A to a subpanel.
Three-wire feeds (no ground) used to be allowed to an outbuilding provided that no other metal pathways like a water line or phone line were present. Now, four-wire feeds are mandatory, no exceptions.
The ground rods are required in either case, and they should be connected to the subpanel ground bar with #6 copper wire. When a three-wire feed is used, the neutral and ground bar must be bonded; when a four-wire feed is used, the neutral and ground bars must not be bonded.
The rating of the main breaker in the subpanel doesn't matter, because it is only acting as a building disconnect. The overcurrent protection is provided by the breaker in the meter/main panel which feeds this outbuilding.
All of the 120V receptacles in the garage should be GFCI protected, either by GFCI breaker or by GFCI receptacle with downstream "LOAD" protection wired. This also includes special-purpose outlets like garage door opener and lighting.
