Skip to Content

Electrical Generator Safety

Each year many Electric Utility customers purchase portable or fixed standby generators. During a power outage, a properly sized and installed standby generator can be a valuable resource to keep a household running. To support a safe work environment for utility customers and employees, it is essential to obtain a permit if you are planning to connect or have already connected any emergency electric generation service to the electrical wiring system of your house or property.


Qualified electricians licensed by the City of Naperville must professionally install a standby generator. Adding a standby generator requires a suitable transfer switch to properly disconnect the electric loads from our utility grid. Adding this switch is a requirement of both the National Electric Code (NEC 701-7 and 702-6) and the Electric Utility for two critical reasons:

  1. The transfer switch prevents the flow of current to our lines during an outage, which could electrocute utility workers attempting to restore power.
  2. The transfer switch prevents feedback of power through the generator when regular electric service has been restored, which could destroy the generator.

For the safety of its employees, the Electric Utility also requires the addition of an outside service disconnect. Major generator manufacturers integrate the automatic transfer switch and the outside service disconnect into a single unit that can be mounted near the existing electric meter.


To make sure that all safety requirements and codes are met, the utility asks residents to follow these procedures:

  • Prior to installing a standby generator with an approved transfer switch, obtain a generator permit. The permit application is also available at the Transportation, Engineering and Development (TED) Business Group, Naperville Municipal Center, 400 S. Eagle St. The cost is $85, which includes a $40 fee for the permit and a $45 fee for the inspection.
  • City staff will review the permit, and appropriate field inspections will be required. Installation of fuel cells, photovoltaic arrays, wind turbines or any other electrical generation devices also require similar permits and inspections by the City.

In cases where utility employees have a reasonable suspicion that an unreported generator is operational on a property during required utility maintenance work, the power to the property will be disconnected during the work. This measure is necessary to prevent the possibility of utility workers' electrocution.

Portable Generator Safety Concerns

Once you have your generator, please take appropriate safety precautions. These concerns also apply to portable generators.

  • Never power the house wiring by simply plugging a portable generator into a wall outlet. Plugging a portable generator into a wall outlet will create the same dangerous conditions as described above. Either plug appliances directly into the portable generator or use a heavy-duty outdoor-rated extension cord.
  • Under no circumstances should portable generators be used indoors. Every year, people die in incidents related to carbon monoxide poisoning from the toxic engine exhaust of a portable generator.

For more information

Ron Ritter

Technical Specialist
TEL: (630) 420-4183 EMAIL:

Department of Public Utilities - Electric

  • 1392 Aurora Avenue
    Naperville, IL 60540

    To set up new service: (630) 420-6059
    For billing questions: (630) 420-6059
    To report an electrical outage: (630) 420-6187
    To report streetlight issues: (630) 420-6187
    For all other electrical inquiries: (630) 420-6181