The 2026 NEC® and the Future of Electrical Systems: Controlling Power and Managing Energy using PCS and EMS

Electrical system design has been rooted in a fundamental principle for a long time: calculate the theoretical, worst-case-scenario load, then build a system robust enough to handle it. Traditional load calculations are based on estimations, assumptions, nameplate ratings, and demand factors. But in an era of distributed generation, energy storage, and heavy but controllable loads (like EV chargers), this model can result in oversized infrastructure or expensive service upgrades that may not really be needed.

The 2026 National Electrical Code (NEC^®) signals a major paradigm shift, formally embracing a smarter approach: managing systems and providing overload protection based on actual, real-time power flow, rather than estimated or predicted load. Acronyms are key, and EMS (energy management system) and PCS (power control system) will become, if they aren’t already, key parts of your DERPS (distributed energy resource power systems!) lexicon.

A change to facilitate power-flow based management in the 2026 NEC was the relocation of existing Articles: Branch-Circuit, Feeder, and Service Load Calculations are now in Article 120 (previously 220), and Energy Management Systems are governed by Article 130 (previously 750). Those are premium “front-of-the-book” locations, signifying their importance and, being sequential Articles, how they are interrelated. The relocation is also recognition that energy management is not a niche application but a common, foundational feature of modern power systems, especially those with on-site power sources and/or storage.

Leveraging these technologies is essential for designing and installing cost-effective, flexible, and powerful next generation electrical systems, and requires understanding the interplay between not just Articles 120 and 130, but also 702 (Optional Standby Systems) and 705 (Interconnected Electric Power Production Sources).

Background

The concepts behind EMS and PCS aren’t new, but code language has played a bit of catch-up. The 2023 NEC used the somewhat unclear phrase “EMS for overload control,” which raised the question: what’s the difference between a “regular” EMS and a special “overload control” version?

The 2026 NEC provides much needed clarification:

• Energy management system (EMS) is the “umbrella” category. An EMS monitors and controls power for reasons other than active safety. Its purpose is typically economic or for convenience – such as reducing energy consumption, saving money by shifting loads off-peak, or improving comfort.
• Power control systems (PCS) are a specific type of EMS with a critical, safety-focused functionality. A PCS is equipment that monitors and controls power specifically to prevent the overload of a service, conductor, or other distribution equipment. This is the active safety “overload control” function that the 2023 NEC was trying to describe.

These changes didn’t occur in a vacuum: safety certification standards played a key role. EMS are covered by UL 916 Energy Management Equipment, which addresses “nice to have” controls for energy efficiency and energy optimization for loads such as lighting and HVAC. 

When the 2023 NEC went to print, PCS were listed to UL 1741, under a Certification Requirement Decision (CRD) for Power Control Systems (PCS) Functionalities. [A CRD is provided by UL staff; it is not a consensus standard, but is intended to become part of a full standard once incorporated through the consensus process.] However, the need for a separate standard became clear, and going forward PCS will be listed to UL 3141 Outline of Investigation for Power Control Systems. UL 3141 addresses “need to have” controls for overload mitigation. The second edition was published in October 2024, and while the final, consensus version is not yet complete, products can be listed to UL 3141 now.

The 2026 NEC aligns with this new evaluation and certification landscape, and just to be crystal clear, notes in Section 130.2 that “evaluation of an energy management system with PCS functionality is different than an evaluation of a general energy management system.”

Types of PCS

All PCS monitor and control power to prevent overload of an electrical service, conductor, and/or power distribution equipment, but there are essentially two flavors of PCS, as described in UL 3141 and defined in the 2026 NEC:

1. A single-source PCS is capable of load management only.

2. A multisource PCS can control power production sources (like PV, ESS, or an EV), with or without load management. This “multisource” capability is the key that unlocks powerful new system design and integration options working in conjunction with Articles 705, 120, and 702.

705.13: Another Option for Interconnection

Section 705.13 has been renamed Power Control Systems (it used to be EMS, but hey EMS has its own Article!), and it now provides a game-changer for PV and storage interconnections: the use of multisource PCS. You could call it “super-sizing” source connections, or consider it the answer to “how do you connect storage to a panelboard that’s already maxed out with PV?”

A PCS can be set to actively limit the current and loading on a busbar(s) and/or conductor(s), functionality referred to as its “control setting” or “setpoint.” This enables connections of power sources with more current than what 705.12 would traditionally allow for load-side connections. Why? Because a listed PCS guarantees safety by actively controlling power source current, ensuring the equipment and/or conductor ratings are never exceeded. 

The benefit is obvious: cost savings and increased utilization of electrical infrastructure. More generation or storage can be added to existing panelboards without expensive upgrades, as conductors and overcurrent protective devices (OCPDs) are sized based on the PCS setpoint, not the aggregate source(s) output.

Be sure to review the Informational Notes in 705.13 – they provide good detail; point to UL 3141 and UL 1741; and state that a PCS may include connection to an electric power production and distribution network (typically the grid), which by extension means it doesn’t have to. Remember the grid may be the primary power source, but it also may not!

120.7: Smarter Load Calculations

The changes to 120.7 (also named Power Control Systems, and formerly located and briefly addressed in 220.70) are profound. The allowance to use a PCS setpoint for load calculations is now a general provision, applying not just to feeders and services, but to branch circuits as well.

There are several requirements when basing load calculations on the presence of a PCS:

• It has to comply with Part II of Article 130 (also called Power Control Systems), which addresses general PCS requirements (several of which are essentially manufacturer-facing). These include what must happen in a malfunction (it must transition to a controlled state that prevents overload); access to adjustable settings; and marking and documentation.
• You have to know what you are doing! The PCS control setting has to be determined by a qualified person, and cannot be any more than 80 percent of the rating of the OCPD for the circuit the PCS is monitoring for overload control.
• Monitored loads (loads for which a PCS can measure current flow) may be controlled by the PCS (the PCS can limit current); uncontrolled by the PCS (the PCS cannot limit current); or a combination, and it matters.

120.7(C) spells out how to calculate the load on branch circuits, feeders, or services with PCS: it is the sum of controlled loads + the sum of noncontrolled loads. Noncontrolled loads are “regular” loads, and as such the “regular” Article 120 calculations apply. If there are only controlled loads, the value for load calculations is simply the PCS control setting.

If the PCS monitors both controlled and noncontrolled loads, the load calc value for the controlled portion must be its “minimum operating current.” Minimum operating current is not defined in the NEC, though an Informational Note in 120.7(C)(1) “clarifies” minimum operating current as a value greater than or equal to zero, representing the minimum current of the controlled loads. This means you’ll have to get data from the equipment manufacturer to quantify this value. For example, an EV charger might only have the capability to ramp down to a minimum of 10 amps; this would be the minimum operating current.

This 37.5A value can be used for the service and feeder load calculations.  This could be helpful if you are doing load calcs for a service, or if this feeder is to an accessory dwelling unit and the goal is to avoid a service upgrade. However – and this is a critical safety point – the controlled feeder conductor must be sized based on the 60A OCPD supplying it, not the 37.5A load calc value.

This is very different from traditional methods! Remember that regardless of these rules and their application, a logical analysis of the end-user experience and the loads they want to operate simultaneously is important: the setpoint of the PCS should be sufficient for the loads to be served. 

As always with the NEC, following 120.7 allowances won’t be unsafe but it may not be “efficient, convenient, or adequate for good service or future expansion of electrical use.”

702.4(A)(3): “Right-Sizing” Optional Standby Systems

The addition of 702.4(A)(3) directly addresses a long-standing problem for battery-backup systems: using traditional load calcs to determine the minimum required capacity for a “backed-up loads panel” could result in over-sized power sources. Previous options for optional standby system capacity were based on whether the system had manual and nonautomatic connection of load (putting the responsibility on the end-user), or if there was automatic load connection (in which case the system either had to be sized for the full load, or have an EMS to limit load to the capacity of the standby source).

702.4(A)(3) is an allowance specifically for multimode inverter-based systems in one- and two-family dwellings and allows “right-sizing” a standby system by using the PCS-listed inverter to manage the loads. The key requirements are:

1. The multimode inverter must be listed as a PCS for overload control.
2. The minimum inverter capacity (its rated output current) must be at least equal to the PCS control current set point.
3. The inverter capacity must be greater than or equal to the load of the largest single piece of utilization equipment.
4. In case of an overload shutdown, the inverter’s reconnection must be nonautomatic.

This is a practical, engineered solution that finally gives installers a code-compliant path to install reasonably-sized, cost-effective backup systems.

Impacts, Benefits, and What’s Next

The impacts of these changes are immediate and far-reaching. Controlled loads and more generation can be connected to existing infrastructure, saving clients significant money on service, feeder, and panelboard upgrades. It enables “smart grid” opportunities and provides the flexibility to install systems (like battery backup) that customers want, without the unnecessary costs resulting from old calculation methods. And this is all achieved while maintaining, and perhaps increasing, safety, as these systems rely on active, real-time monitoring to provide overload protection, not just passive overcurrent protection.

The 2026 NEC laid the groundwork, but there’s still work to do.

• “Minimum operating current,” as used in 120.7(C), is undefined, putting the burden on installers and designers to get the right data for a variety of different equipment.
• While “qualified person” is defined in the NEC, 130.7(B) requires the PCS control setting be “determined by a qualified person.” The industry and AHJs will need to establish what this determination means in practice for designing and commissioning these systems.
• As with any new code language, there are potential “illogical” quirks that may only become apparent when put into practice. As an example, see the preceding sizing example on 120.7: the system is safe, but there is ambiguity related to minimum feeder ampacity that isn’t consistent with requirements elsewhere in the NEC, suggesting further refinement will happen in the 2029 code cycle.

Ultimately, the 2026 NEC has embraced a new philosophy. By formally integrating power control systems, the code recognizes that the future of electrical system design is not just about building bigger, but about building smarter. Reach out to us at Solar Tech Collective if you’re interested in staying informed and engaged on developments in codes and standards related to power control systems.

This article was published in PV Magazine USA as 2026 National Electrical Code changes: PCS and EMS part 1 and 2026 National Electrical Code changes: PCS and EMS part 2.