Province of Ontario - Electrical Safety Code Bulletins

For the latest information related to residential DC ESS installation in Ontatio, please visit the OESC website.

Relevant bulletins:

October 2026 -  Bulletin 64-8-4 Battery based energy storage systems (ESS) at residential occupancies Rules 64-1100 and 64-924 

May 2025 - Bulletin 64-7-3 Installation and Approval of Energy Storage Systems Rules 2-024, 64-900, 64-1100, 84-002 and 84-022 

May 2025 - Bulletin 64-1-5 Utility-interactive inverters Rules 14-402, 14-414, 14-700, 64-060, 64-102, 64-112, 84-010, 84-020, and 84-022

Highlights -

Installation of Rolls S48-100/800LFP STACK-LV DC ESS in the province of Ontario

The 2024 Ontario Electrical Safety Code (OESC) adopted a new section “Installation of energy storage systems at residential occupancies” and modified several other related Rules. 

Rule 64-1100 provides the requirements for location and separation of ESS installed at residential occupancies either within a dwelling unit or other spaces of the residential occupancy including outdoors. 

Rule 64-1100 is applicable to all ESS installed at residential occupancies including those utilizing batteries which shall be approved and be installed in accordance with the manufacturer’s installation instructions per Rule 64-1002 

Location:

Rule 64-1100 10) prohibits ESS from being installed in sleeping areas, or rooms opening directly into sleeping areas  

Rule 64-1100 11) requires a smoke alarm or smoke detector to be installed when an ESS is installed within a dwelling unit. The smoke alarm or detector shall be installed in the room where the ESS is located and shall be installed in accordance with Section 32. Notwithstanding Rule 64-1100 11), which is applicable to the ESS as a complete approved system, the installation of a smoke alarm/detector shall apply to the battery portion when installed in a separate location from the remainder of the equipment making up the ESS. The smoke alarm/detector is intended to be interconnected where required by the Ontario Building Code (OBC).

Based on Subrule 3) of Rule 64-1100, ESS in a dwelling unit or residential occupancy are permitted to be installed below the lowest level of egress with the conditions listed in Subrule 1) and 2) of Rule 64-1100 for a dedicated room or utility room. 

ESS ventilation and clearance requirements shall be in accordance with the manufacturer’s installation instructions. If not addressed by the manufacturer’s installation instructions, ventilation of battery rooms or areas shall be in accordance with Rules 2-324 and 64-802. In properties where there are multiple buildings and not all of them are residential, Rule 64-1100 requirements and this bulletin are not applicable to buildings not associated with the dwelling unit, such as a drive shed on a rural property, or a structure built for the sole purpose of housing ESS equipment. Minimum clearance of 3 m from a residential building is required based on the intent of Rule 64-926. 

Properties that are zoned as mixed-use buildings such as buildings with street-level retail having a commercial shop front on the ground floor and residential dwelling(s) above, are subject to the requirements of Rule 64-1100 and this Bulletin. 

Products evaluated to ANSI/CAN/UL 9540 3rd edition that are marked to indicate “Suitable for Use in Residential Non-Habitable Locations” have led to questions regarding installation locations other than those identified by the Ontario Electrical Safety Code (OESC). Manufacturers and installers refer to OESC Rule 64-1100 9) and manufacturer’s instructions as permitting this, however, no criteria for acceptance are provided by the Code.