Lessons Learned Issued in 2000
Power Strip Overheats and Causes Fire

Date: January 13, 2000

Identifier: 2000-RL-HNF-0002

Lessons Learned Statement:
Surge protection devices in some older model multi-outlet power strips can overheat and create a potential fire hazard.

Discussion of Activities:
On August 28, 1999, a Kensington Power Tree 20, model # 62162 multi-outlet power strip with surge protection failed and started a small fire in a trailer at the Stanford Linear Accelerator Center (SLAC). This graphic shows the damaged power strip.

Analysis:
Analysis of the failed power strip revealed that the metal oxide varistor (MOV) in the surge protector overheated.
Underwriters Laboratories Standard UL 1449, 2nd Edition, Standard For Safety For Transient Voltage Surge Suppressors, now requires thermal protection in power strips. This protection is provided by a thermal fuse located next to the MOV.

Recommended actions:
Units of this make and model located at SLAC were replaced. No product recall has been received but users are encouraged to inspect their power strips. Any that show signs of overheating, such as discoloration and/or distortion, should be replaced with a newer model that complies with the latest edition of UL 1449.

Estimated Savings/Cost Avoidance: N/A

Priority Descriptor: YELLOW/Caution

Work / Function: Business and Support Services

Hanford Functional Category: N/A

Hazard: Electrical/NEC, Fire / Smoke / NFPA

ISM Core Function: Analyze Hazards

Originator: Ishwar Garg, Stanford Linear Accelerator Center, (650) 926-2039

Contact: Project Hanford Lessons Learned Coordinator; (509) 373-7664; FAX 376-6112; e-mail: PHMC_Lessons_Learned@rl.gov

Authorized Derivative Classifier: Not required

Reviewing Official: John Bickford

Keywords: power strip, fire, metal oxide varistor

References:
SLAC Safety Bulletin