Enroute controller issued FL300 when thinking FL330 was issued which lead to a loss of separation.

Attributes
ACN	1060975
Time
Date	201301
Local Time Of Day	0001-0600
Place
Locale Reference	ZZZ.ARTCC
State Reference	US
Aircraft 1
Make Model Name	B757-300
Operating Under FAR Part	Part 121
Flight Phase	Descent
Flight Plan	IFR
Aircraft 2
Make Model Name	DC-10 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Person 1
Function	Enroute
Qualification	Air Traffic Control Fully Certified
Person 2
Function	Enroute
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types Deviation - Procedural Clearance

Narrative:

I meant to issue fl 330 but actually issued FL300.

Original NASA ASRS Text

Title: Enroute Controller issued FL300 when thinking FL330 was issued which lead to a loss of separation.

Narrative: I meant to issue FL 330 but actually issued FL300.

Data retrieved from NASA's ASRS site as of July 2013 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.