Connecting a Generator

The following provides guidance regarding the process for connecting a generator to the ENWIN distribution system. A generator is electrically connected to the ENWIN distribution system regardless of whether it is connected upstream or downstream of the meter. An electricity storage device is considered to be a generator. A generator proponent wishing to connect to the ENWIN distribution system is required to apply to ENWIN for such a connection.

ENWIN follows the rules of the Ontario Energy Board’s (“OEB”) Distribution System Code and Distributed Energy Resources Connection Procedures (“DERCP”) for generator connections. Please refer to the OEB’s website for the latest version of these documents:

Distribution System Code

Distributed Energy Resources Connection Procedures

The DERCP provides complete details and timelines (including flowcharts) of the connection process.

Generation Connection Information Packages

Micro Embedded Generation Facility (up to and including 10 kW)

Connection Guide

Apply for connection using the following online forms:

Micro Embedded Generation Facility Application Form

Micro Embedded Generation Facility Connection Agreement

Small, Mid-Sized and Large Generation Facilities (larger than 10 kW)

Connection Guide

Preliminary Consultation Information Request

Connection Impact Assessment Study Application

Connection Impact Assessment Study Application Instructions

Connection Impact Assessment Study Agreement - Fillable

Approved Meter Sockets and Cabinets

Metering Instructions

SCADA Technical Requirements

SCADA Information Form

Confirmation of Verification of Evidence Report ("COVER")

Sample Protection Philosophy as in the DERCP Appendix A

Sample Connection Agreement for a Small or Mid-sized Embedded Generation Facility

Emergency Backup Generation Facility  

Please refer to Sections 1.2 and 6.2.1 of the Distribution System Code for the requirements to be classified as an Emergency Backup Generation Facility.

If your facility is intended to operate as an Emergency Backup Generation Facility, please submit a Single Line Diagram (SLD), your proposed transfer switch model number and manual to for review and approval. 

In addition, the SLD should clearly show the: utility source, hydro meter, Automatic Transfer Switch including model number, Generator and Customer Load at a minimum to be considered a complete SLD.

Note - Residential and small commercial customers should note that ENWIN does not permit meter socket plug-in emergency back-up transfer devices. For further details refer to ENWIN's Conditions of Service Section: 2.3.6 Emergency Backup Generation Facilities.

Once the SLD and transfer switch is approved and the facility constructed, a Confirmation of Verification of Evidence Report ("COVER") is required to be submitted for review and approval.

Specifically, sections 1, 2 and 4D of the COVER form need to be completed. Section 2 must include professional designation of qualified person able to perform the work.

A completed package includes:

COVER, SLD, Transfer Switch Model Number and Manual to ensure acceptable Automatic Transfer Switch (ATS) model. All these items should be sent to for review and approval.

ENWIN DER Capacity Mapping Application

Use the ENWIN Distributed Energy Resources (“DER”) Capacity Mapping Application (Restricted Feeder List) to see if there is capacity to connect a project at a particular Station/Feeder by simply entering in the address of the proposed project location. Follow the instructions at the link below, and feel free to contact us to confirm project details for a specific location, or submit a Preliminary Consultation Information Request (“PCIR”).

This tool will assist in the completion of the Connection Impact Assessment (“CIA”) Study Application and the applicant may choose to omit submitting the optional PCIR form. The intent of the application is to assist applicants in providing any feeder restrictions on the ENWIN system and reduce wait times to receive completed Preliminary Consultation Reports ("PCR"). Please ensure to read the disclaimer associated with the tool.

Applicants should note that other applications for capacity may pre-date your application and may be assigned remaining capacity in advance of your application. As a reminder, capacity is allocated as part of the completed CIA process, however, ENWIN will notify customers if there is risk to their capacity allocation application, where possible.

Click here to access the ENWIN DER Capacity Mapping Application

Hydro One Technical Interconnection Requirements 

ENWIN has adopted Hydro One's Technical Interconnection Requirements ("TIR"), which outline design requirements for distributed generators. Applicants should ensure they meet all requirements as outlined in the TIR, which include the requirement of grounded generation. ENWIN will not accept ungrounded generation. Therefore, applicants should ensure a zig-zag or grounding transformer is included in their designs.

Click here to access the Hydro One Technical Interconnection Requirements

Connection Impact Assessment (CIA) Fees 

A Connection Impact Assessment ("CIA") is a more detailed assessment of a project’s impact to the grid. The results include a technical report outlining project feasibility, technical specifications needed for the project, and the impacts the project would have on the distribution grid. 

Generator Project Size ENWIN Cost
Up to 50kW $0
Equal to and above 50kW and below 500kW $5,000 *
Equal to and above 500kW and below 1000kW $11,500
Equal to and above 1000kW $13,500


Projects that are greater than 500kW will require Hydro One CIAs as well, refer to the Hydro One website for the additional costs.

* There will be an additional $1,000 Station Impact Assessment charge for projects equal to and above 50kW and below 500kW connecting to Walker 2 Transformer Station as it is ENWIN owned.

For any questions or confirmation of costs customers should contact Technical Services at or 519-251-7303

Net Metering - ENWIN Requirements

Customers in Ontario are also eligible to participate in Net Metering as set out in Ontario Regulation 541/05 – Net Metering. 

Net Metering allows eligible customers with specific generation facilities to reduce their net energy costs by exporting surplus energy back onto the utility distribution system, earning credit against the energy they consume from the distribution system. Excess generation credits can be carried forward for a consecutive 12-month period to offset future electricity costs.

Starting July 1, 2022, amendments to Ontario Regulation 541/05 will also allow customers to enter into third-party ownership arrangements like leasing, renting, financing and power purchase agreements for the provision of renewable generation equipment or to purchase renewable electricity for the purposes of Net Metering. This relationship is solely between the customer and the third party. 

A customer who enters into any such agreement with a third party will maintain a Net Metering agreement with ENWIN and be billed on a Net Metering basis in the same way as a customer who is not party to a third-party arrangement and, instead, owns their own renewable generation equipment.

You can participate if you have a generator, or have an arrangement with a third party to provide generation, that meets all of the following conditions:

  1. The electricity is generated primarily for your own use.
  2. The electricity generated is conveyed to your own consumption point without reliance on the ENWIN distribution system.
  3. The electricity is generated from a renewable energy source.
  4. Any electricity that is generated in excess of what you consume is conveyed into the ENWIN distribution system.
  5. You or the third party are not party to any contract or agreement, other than a Net Metering agreement, that provides for the sale, in whole or in part, of the electricity that is conveyed into ENWIN’s distribution system.

Further information on the specific requirements can be found by referring to Ontario Regulation 541/05

More information is also available by visiting Retailer forms and templates: net metering and energy contracts on the Ontario Energy Board’s website, including additional information related to third-party Net Metering arrangements.

Net Metering - Technical Requirements

To participate in the Net Metering program, you will need to meet all parallel generation requirements outlined above. 

You must install an isolation device satisfying Section 84 of the Ontario Electrical Safety Code, located outside, typically near the meter, and agree to give utility staff access to, and operation of this device, as needed, for maintenance and repair of the distribution system.

Customers entering into third-party Net Metering arrangements may also be required to submit a completed Schedule G for the purposes of confirming to ENWIN that you have been provided certain information by the third party as required under subsection 7(1)(f) of Ontario Regulation 541/05.

Please note that accessible versions of all documents on this webpage are available upon request.

For any questions regarding the info on this web page the customer should contact Technical Services at or 519-251-7303.