Technical & Electrical Code Information
Installing our Energy Management Devices will allow an electrician to exclude the Electric Vehicle charging portion and possibly other device loads from the residential electrical load calculation found in your U.S. and Canadian codebook. These are the electrical code reference that relate to this:
USA:
NEC 220.70 Energy Management Systems (EMSs) "If an energy management system (EMS) is used to limit the current to a feeder or service in accordance with 750.30, a single value equal to the maximum ampere setpoint of the EMS shall be permitted to be used in load calculations for the feeder or service." NEC - National Electrical Code 2023
Other Applicable Codes: NEC articles 625, 750
Canada:
8-106(10,11) Use of demand factors
For the purposes of Rules 8-200 1) a) vi), 8-202 3) d), 8-204 1) d), 8-206 1) d), 8-208 1) d), and 8-210 c), where an electric vehicle energy management system as described in Subrule 10) monitors the consumer’s service and feeders and controls the electric vehicle supply equipment loads in accordance with Rule 8-500, the demand load for the electric vehicle supply equipment shall not be required to be considered in the determination of the calculated load.
8-500 Electric vehicle energy management systems
1) Electric vehicle energy management systems shall be permitted to monitor electrical loads and to control electric vehicle supply equipment loads.
2) An electric vehicle energy management system shall not cause the load of a branch circuit, feeder, or service to exceed the requirements of Rule 8-104 5) or 6
3) An electric vehicle energy management system shall be permitted to control electrical power by remote means.
Discussion of code interpretations:
In Canada, some have asked if putting our current monitoring devices on the lines side of a panel disconnect or main breaker would be an electrical code violation. This is addressed in CEC 6-212 (1) & (2). Although subrule one seems to indicate that this may be a problem, the second paragraph provides this specific clarification: "CEC 6-212 (2)* Notwithstanding Subrule 1), service equipment designed for accommodating current monitoring devices or other associated electrical equipment that must, for its operation, be connected to the line side of the service disconnecting means, shall be permitted". This clearly allows for our current monitors to be installed in the service equipment.
Further to this, some have questioned the phrase "designed for accommodating" in this code reference, indicating that a manufacturer of service equipment may need to provide specific permission for this application. A thorough consideration of this phrase, as well as related phrases, in the framework of how they are used in the CEC, reveals that this would be a departure from the intended usage throughout the document. When cited in the CEC it is mainly used in the practical sense as it relates to having space for, or able to contain. Some examples in the CEC are under Definitions and Recreational vehicle park, 22-702 Special terminology under Dry well, 72-112 Appendix B, etc...There are fewer additional instances where it is used to allow a modification of a specific code to allow for a practical function; for example CEC12-1006. There are no instances where this phrasing or similar ones would indicate that a manufacturer would have to specifically state that it could be used in this way. Therefore, when considering the context in which this phrase is used, it strongly indicates that as long as there is practical space for the current monitoring devices, and they need to be located in the service equipment for their operation, they should be allowed.
To address any space concerns, we have divided our current monitoring devices into two models to allow for smaller ones in the models for 100A service sizes and below (EVEMS240-100) and larger ones for the services sizes 125A and above (EVEMS240-200). As well, you will notice on our specifications sheet that the shape of our current monitoring devices are thinner on two sides to help them to easily fit into the service area.
This along with our approved product front label that states "The electromagnetic current monitoring devices included can be installed in the main electrical service disconnect area" combined with our installation manual that explains how this is to be done safely, clearly shows that our products fit into a safe and code compliant installation accepted in both the U.S. and Canada.
We have also made clear on our product front label that our energy managers are approved for general use and as an EVEMS / EMS. It also states that an optional neutral slice can be made in the enclosure and how it is to be done with the accessories included.
In Multi Residential (MURB) applications an additional consideration is required. According the the CEC 8-500 2) An electric vehicle energy management system shall not cause the load of a branch circuit, feeder, or service to exceed the requirements of Rule 8-104 5) or 6. Therefor in this application a energy manger must monitor the feeder to the suite with our standard EVEMS240 series, but also the main service that this suite is connected to. Our HUB system was specifically designed to address this code reference as it has multi-stage monitoring and power access equalization capabilities.
As a result of using Energy Management Systems or Power Control Systems, the effective load calculation of the electrical service will not change despite being able to operate a high-current device like an EV charger for the majority, if not all of the operating cycle each day. This is not just simply switching between two loads as that method is an inefficient way to control these loads and creates much longer off times as a result. To provide additional charging efficiency our EVEMS/EMS/PCS devices read instantaneous total service current 24 hours a day and constantly feed this into a computer that filters out things like problematic electrical fluctuations, inrush currents, and things like these to better determine if there is the capacity for charging, or not. This will provide for the longest charge cycle without causing potentially damaging oscillations or unnecessary stoppages.
Our products are designed for electrical service sizes of 60A - 100A, 125A, 150A & 200A and accommodate the most common EV charge rates up to using a 100A breaker. To add flexibility, we have also included settings for other electrical devices that can tolerate load shedding.
When your EVEMS/EMS/PCS installation is completed, an additional safety feature puts all settings behind a built-in partition that keeps potentially curious fingers from changing them thereby creating dangerous situations and unnecessary call-backs. This provides for a safer and cleaner finished product.
Our Fail-Safe de-energization is also an important consideration when selecting energy management systems. Many other devices use a latching relay design that can leave the controlled device in a “powered state” indefinitely if the controller fails. This presents a serious electrical safety concern. The Black Box Energy Manager uses a switching system that de-energizes the end device and will prevent this safety issue. This is the preferred state of electrical device failure by Electrical Inspections and regulators
We have worked closely with Regulators and Authorities Having Jurisdictions (AHJ) or Inspection Agencies to address this and other code questions. This proactive approach has allowed our approved products to operate as intended and be accepted as compliant from coast to coast.
For further information please contact us as we are happy to hear from our customers and authorities having jurisdiction for a smooth adoption by contractors and regulators.
* References taken from, and/or referred to above, are from CSA Canadian Electrical Code (CEC) 2021, 2024 and the National Electrical Code (NEC)