Electric vehicles as energy-production source – Code File, September 2022
September 20, 2022 | By Nansy Hanna, P.Eng.
Let us ensure they are installed in a Code-compliant manner so we can reap their benefits safely.
September 20, 2022 – Popular new acronyms such as V2G, V2H, V2B, etc., refer to changing electric vehicles (EVs) from a means of transportation into energy storage facilities, capable of exchanging energy with the grid, home, load or building.
Before we explore any CE Code installation requirements, let us agree on an important concept: during the discharge of energy from the vehicle, it is considered an energy-production source.
This is true regardless of whether that energy is consumed by the building/home, or whether there is a balance of energy going back to the grid. The moment energy starts flowing away from the vehicle, it is considered an energy-production source.
With that concept established, here are the main CE Code requirements:
• Rule 86-308 requires that EV supply equipment (EVSE) be marked when it is an electric power production source (bi-directional power).
• Rule 86-308(1) requires that other parts of a system—either on or offboard of the vehicle—that are identified for and intended to be interconnected to a vehicle, and also serve as an optional standby system or an electric power production source, be marked accordingly.
• When an EV is used as energy-production source, Rule 86-308(2) stipulates that the requirements of Section 84 apply.
Marking equipment as per Rule 86-308(1) is important, as it identifies equipment with the capability for bi-directional power, and that it has been certified and tested accordingly. The application of Section 84 ensures that the vehicle’s interconnectivity with the building’s electrical system and the grid is safe.
One of the critical requirements of Section 84 is found in Rule 84-008 “Loss of supply authority voltage”. This rule requires that, upon loss of power, any electricity production source—including the EVSE in our discussion—is automatically disconnected from the grid. This is very important for safety, regardless of the capacity of the EVSE and whether that capacity is already consumed by the building loads under normal operating conditions.
Any system that produces even small amounts of electricity can be potentially dangerous. Improperly installed systems can create serious safety hazards to property owners, employees, visitors, supply authority workers, etc. For example, as supply authority workers perform repairs during an outage, even a small amount of power flowing back to the grid through a vehicle could lead to electrocution.
The requirement in Rule 84-008 can be met with the use of an inverter that is suitable for interconnection with electric power production sources and designed to serve as a disconnection device. These inverters and/or power production units are marked as “utility interactive inverter” or “grid-support utility interactive inverter”. So, you could connect the EV through a certified inverter or power production unit to ensure compliance.
Another option is to use EVSE that is marked and specifically certified for that purpose. (UL 9741 “Outline of investigation for electric vehicle power export equipment [EVPE]” is currently the only standard in North America for certifying bi-directional EVSE.)
Other important Section 84 requirements include:
• Ensuring the interconnection arrangement is in accordance with the supply authority (Rule 84-004).
• Disconnecting means for EVSE, Rule 84-020.
• Disconnecting means readily accessible to the supply authority, Rule 84-024.
• Warning notice and single-line diagram indicating there is an interconnected system at the premises. These need to in a conspicuous place, visible to first responders and the supply authority.
Where an electrical installation includes energy storage systems and/or bi-directional EVSE operating in parallel with the supply authority—and the aggregate rating of the system(s) installed at the same time is in excess of 10 kW—some AHJs (e.g. Ontario’s Electrical Safety Authority) require the electrical design to be submitted for review prior to commencement of work.
We are already seeing vehicle-to-grid installations in Canada; they help support renewable energy sources and balance consumption by charging off-peak and using stored energy during peak demand. They also enable our EVs to serve as emergency back-up power. Let us ensure they are installed in a Code-compliant manner so we can reap their benefits safely.
Nansy Hanna, P.Eng., is senior director, Engineering & Regulations, at Ontario’s Electrical Safety Authority (ESA). She is also chair of the Canadian Advisory Council on Electrical Safety (CACES) and a member of the ULC Advisory Council and CSA Technical Committee on CE Code-Part I. She can be reached at email@example.com.
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