Lessons Learned Database



Title:

HEPA Vacuums Draw Current above the Rating of Power Cords

Identifier:

2001-RL-HNF-0030

Date:

2001-08-16

Lesson Learned Statement:

Euroclean Model UZ948 HEPA vacuum cleaners draw current above that for which the cords and plugs are rated.

Discussion:

A Euroclean Model UZ948 HEPA Vacuum used by BHI at U-Plant and at other Hanford facilities tripped the circuit breaker supplying its outlet. Evaluation by the chairman of the Hanford Electrical Codes Board determined that the vacuum nameplate rating was more than the rated capacity of the cord and plug. Receptacle circuits compatible with the installed attachment plug are not adequate for the vacuum load. These conditions can lead to overheating of the attachment plug, flexible cord, receptacle, or circuit wiring and do not comply with the National Electrical Code (NEC).

This notice applies specifically to Euroclean Model UZ948, however other models may have similar problems. 

Analysis:

The Model UZ-948 vacuum has three motors that provide a maximum flow rate of 270 CFM. When the unit is started, one switch turns on the first two motors and a second switch turns on the last motor. The high amperage draw when the unit is started may trip circuit breakers. During a simulated field test of a unit at the ALARA Center, the following line currents were recorded using a digital ammeter:

Motors 1 and 2 running under load (moving air only) - 11.8 Amperes
Motors 1 and 2 running under no load (suction hose blocked) - 10.5 Amperes
Motors 1, 2, and 3 running under load (moving air only) - 14.6 Amperes
Motors 1, 2, and 3 running under no load (suction hose blocked) 11.8 Amperes

Because the normal load on this unit is the work involved in moving air, blocking the suction hose will reflect the no load condition. As expected, the line currents dropped when the air movement stopped. However, the actual loaded condition in the field will include moving air along with other material containing additional mass. The combination of air and additional mass will require more work, and thus will present an additional load on the unit. The nameplate on the unit lists 14 Amperes full load for 2 motors and 19.4 Amperes full load for 3 motors. 

Other problems identified with the equipment include:
  1. The attachment plug is rated 15 Amperes, and is not suitable for a 19.4 Ampere load.
  2. The cord is 14/3 gage and is rated for 18 Amperes according to the NEC Table 400-5(A).
  3. Because the attachment plug is rated 15 Amperes, it could be used on a 5-15R or a 5-20R receptacle. Those receptacles are limited to 80% of their ratings (12 Amperes for 5-15R and 16 Amperes for 5-20R) for a continuous load. Therefore, powering the unit from a standard receptacle would overload the receptacle.
  4. The attachment plug did not meet the requirements for a motor disconnect and was not horsepower rated. 
Operating these vacuums in their current configuration risks overheating the receptacle, the attachment plug, or the connecting cable. 

Recommended Actions:

Facilities with Euroclean Model UZ948 HEPA vacuum cleaners should replace or repair the affected units according to the options below:
* Return/retire existing units and replace with new equipment listed with a nationally recognized testing laboratory such as Underwriters Laboratory (UL).
* Replace the 14/3 gage power cord with 12/3 gage cord and replace the attachment plug with a 5-30P.
* Replace the attachment plug with a 5-20P and physically disconnect motor No. 3.

Originator:

Fluor Hanford, Inc.

Validator:

John Bickford

Contact:

Project Hanford Lessons Learned Coordinator; (509) 373-7664;

Name Of Authorized Derivative Classifier:

Not required

Name Of Reviewing Official:

John Bickford

Priority Descriptor:

Yellow / Caution

Keywords:

HEPA vacuum; Euroclean; circuit breaker; electrical overload

References:

HWESB Minutes for 7/11/2001
Electrical Safety Bulletin ESB-2001-03

Information in this report is accurate to the best of our knowledge. As means of measuring the effectiveness of this report please use the "Comment" link at the bottom of this page to notify the Lessons Learned Web Site Administrator of any action taken as a result of this report or of any technical inaccuracies you find. Your feedback is important and appreciated.

DOE Function / Work Categories:

Business and Support Services
Decontamination & Decommissioning

ISM Category:

Analyze Hazards

Hazard:

Electrical / NEC
Fire / Smoke / NFPA

End of Lesson!

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