B757 captain reported the cockpit window shattered in flight after the window heat was turned on.

Attributes
ACN	1516625
Time
Date	201802
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.ARTCC
State Reference	US
Aircraft 1
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Route In Use	Direct Oceanic
Flight Plan	IFR
Component
Aircraft Component	Cockpit Window
Person 1
Function	Captain Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Flight Instructor Flight Crew Instrument Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 150 Flight Crew Total 12900 Flight Crew Type 5200
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural MEL Deviation - Procedural FAR Deviation - Procedural Maintenance Deviation - Procedural Published Material / Policy

Narrative:

Maintenance asked me to turn on windshield heat (MEL'd) to test the system. They stated if there were no issues; they would be able to clear the MEL upon landing.at xa:45 I turned on the affected heat as instructed. At xa:54 the captain front windshield shattered.we [requested priority handing] and performed the QRH procedure. We also began a descent and an immediate speed reduction and continued without further event with a successful landing.

Original NASA ASRS Text

Title: B757 Captain reported the cockpit window shattered in flight after the window heat was turned on.

Narrative: Maintenance asked me to turn on windshield heat (MEL'd) to test the system. They stated if there were no issues; they would be able to clear the MEL upon landing.At XA:45 I turned on the affected heat as instructed. At XA:54 the Captain front windshield shattered.We [requested priority handing] and performed the QRH procedure. We also began a descent and an immediate speed reduction and continued without further event with a successful landing.

Data retrieved from NASA's ASRS site 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.