Narrative:

Due to VFR WX, loss of separation was not a problem. However, mht TRACON and tower lost radar, frequencys, landlines, commercial lines for 20 minutes. No backups kicked in.

Google
 

Original NASA ASRS Text

Title: COMPLETE POWER FAILURE OCCURRED AT AIR TRAFFIC FAC. BACKUP POWER DID NOT WORK.

Narrative: DUE TO VFR WX, LOSS OF SEPARATION WAS NOT A PROBLEM. HOWEVER, MHT TRACON AND TWR LOST RADAR, FREQS, LANDLINES, COMMERCIAL LINES FOR 20 MINUTES. NO BACKUPS KICKED IN.

Data retrieved from NASA's ASRS site as of August 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.