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 US and Canadian codebook.
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
NEC 70-619 Article 750 and part 625 "750.1 Scope: This article applies to the installation and operation of energy management systems." NEC - National Electrical Code 2020
CEC 8-500 & 8-106(10,11) "CEC 8-106 (11) 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." CEC - Canadian Electrical Code 2021 by CSA
As a result, 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 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 60A breaker. To add flexibility, we have also included a setting for other electrical devices that can tolerate load shedding.
When your EVEMS installation is completed, an additional safety feature puts all settings behind a built-in partition that keeps potentially curious fingers from changing them and 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
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 code reference 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 US 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.
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 100A 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.
We have worked closely with Regulators and Jurisdictions Having Authority 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.