Solution Summary: Safe Work Practices When Using Portable Generators
Portable generators are gasoline-powered equipment used to generate electricity for various construction tools and equipment and can present various hazards if used incorrectly. The common causes of injuries and fatalies that arise from using these equipment are electrical and fire hazards and exposure to carbon monoxide. This solution outlines some general safe work practices to help reduce these hazards for the user and utility line workers if they are working to restore power during an outage.
In order to help prevent electrical hazards, always maintain and operate portable generators according to the manufacturer's guidelines and recommended use such as utilizing ground-fault circuit interruptors. In general, it is important to plug electrical appliances directly into the generator using the appliance manufacturer's cords. In the event that extension cords need to be used, be sure they are heavy-duty and are of the grounded type (3-pronged). They must be rated for the application and the load to be served to avoid overloading the extension cord. Caution must also be taken to avoid exceeding the capacity of the generator (Figure 1). In addition, always uncoil cords and lay them in flat open locations as cords can get hot and become a fire hazard.
Figure 1. 3-pronged heavy-duty cords directly plugged into the generator. This generator is not connected to the structure's electrical main panel. (Source: http://www.jpenergy.com/generator-safety)
- Not operate portable generators indoors or in partially-enclosed areas unless the engines can be located outside away from air intakes so that engine exhaust is not drawn indoors where the work is being done. However, an exception to this rule might be during an emergency rescue situation in which other options are not available provided that equipment operators, assisting personnel, and the victim are donning supplied-air respirators
- Learn to recognize the signs and symptoms of CO overexposure which may include headache, nausea, weakness, dizziness, visual disturbances, changes in personality, and loss of consciousness
- Use personal CO monitors (see below) where potential sources of CO exist. These monitors should be equipped with audible alarms to alert workers when CO concentrations are too high or when it exceeds the NIOSH CO Ceiling limit at 200 parts per million
Personal CO Monitoring Instruments
While this is not a comprehensive list of commerically-available options, here are a couple of personal CO monitors from two manufacturers:
BW Technologies GasAlert Extreme Single Gas (CO) Monitor
- Measuring Range (PPM): 0-1000
- Visual, vibrating, and 95 dB audible alarms for high, low, STEL (Short Term Exposure Limit), and TWA (Time-weighted Average)
- Approved for Class I, Div 1 and CLass II, Div 1 environments
- Replaceable batteries and sensors
- Includes calibration cap and hose
- Optional: BW Technologies Infrared Connectivity Kit and Software is available for linking to a computer for data downloads and access to instrument set up options
SENSIT P100 Personal CO Monitor
- Measuring Range (PPM): 0-999
- Visual, vibrating, and 90 dB audible alarms for high, low, STEL (Short Term Exposure Limit), and TWA (Time-weighted Average)
- Datalogging: Up to 100 alarm events (downloaded through SmartLink Software)
Contact with electric current is a major cause of injury and death among construction workers (Janicak 2008). In 2012, the Census of Fatal Occupational Injuries (CFOI) data produced by the Bureau of Labor Statistics (BLS) indicated that contact with electric current was the fourth leading cause of work related deaths—after falls, transportation incidents, and contact with objects and equipment (BLS 2012). Electricity can cause electric burns, electrocution, shock, arc flash/blast, fires and explosions. Incorrect use of portable generators can contribute to the risk of electrical hazards.
One of the major causes of an electrocution hazard is contact with overhead power lines and energized sources. Overhead power lines are particularly hazardous since they carry high-voltage electricity. Although electrocution is considered the main risk, other important hazards of working near or on high-voltage lines include electrical shock, burns, and falls to lower levels. These types of hazards happen when the body becomes part of the electric circuit, whether by direct contact with an energized source or by contact with a conductive material that has become energized. The severity of the electrical hazard depends on several factors, including the length of exposure time, energy deposited into the body, the pathway through the body, wetness or dryness of the surface and the amount of current. Utility line workers repairing power lines may unexpectedly encounter high voltage and suffer a fatal shock through portable generator backfeed.
Carbon monoxide (CO) is a poisonous, colorless, odorless, and tasteless gas. Although it has no detectable odor, CO is often mixed with other gases that do have an odor. CO results from the incomplete burning of natural gas and any other material containing carbon such as gasoline, kerosene, oil, propane, coal, or wood. In construction, it is common to use gasoline-powered equipment that can lead to the risk for carbon monoxide toxicity, especially in poorly ventilated or confined spaces.
How Risks are Reduced:
Adhering to the portable generator's manufacturer guidelines and use recommendations can reduce the risk of electrical hazards through making proper grounded connections of tools and applicances. In addition, the practice of not connecting a portable generator to a structure (without a power transfer switch installed) eliminates the risk of electrocution for utility line workers.
By taking a proactive approach in recognizing symptoms and monitoring CO levels before and during the operation of portable generators, the risk for CO toxicity can be reduced or eliminated.
- Before the use of portable generators, inspect for damage or loose fuel lines
- Always keep portable generators dry and never operate under wet conditions
Le, Jean Christophe, MPH - CPWR - The Center for Construction for Research and Training
To obtain information, visit Grounding Requirements for Portable Generators
To obtain information, visit BW Technologies GasAlert Extreme Single Gas Monitors or contact 1-877-723-2878 firstname.lastname@example.org
CPWR Hazard Alert Card
To obtain information, visit Carbon Monoxide Poisoining