Switchboard vs Switchgear: What's the Difference?

A switchboard is a free-standing electrical distribution assembly built to UL 891 and NEMA PB 2, typically front-access only, with fixed-mounted branch devices rated up to about 4,000 amps and short-circuit interrupting ratings up to roughly 100 kA. Switchgear is a more robust assembly built to UL 1558 and IEEE C37.20.1 (or, at medium voltage, IEEE C37.20.2/.3), with drawout circuit breakers, front and rear access, higher short-circuit interrupting ratings, typically 65–200 kA on low-voltage equipment, and a short-time withstand rating that allows selective coordination. Both assemblies distribute and protect electrical power, but switchgear is engineered for higher fault duty, live maintainability, and the reliability levels demanded by industrial, utility, and mission-critical facilities.

The remainder of this article compares the two at a glance, defines each in its own right, summarizes medium-voltage switchgear for completeness, walks through the engineering distinctions that matter in practice, and ends with the specific NEC articles that effectively mandate switchgear over switchboards.

Comparison at a Glance

The table below summarizes the differences most readers came here to find. The sections that follow expand on each row.

What Is a Switchboard

A switchboard is a free-standing assembly of switching, protection, and metering equipment that takes power from a service entrance or feeder and distributes it to multiple downstream branch circuits. Switchboards are built to NEMA PB 2 (*Deadfront Distribution Switchboards*) and listed to UL 891 (*Switchboards*). When a switchboard meets the service-entrance requirements of NEC Article 230 and is labeled accordingly, it can serve as the building's service-entrance equipment.

Construction is straightforward. The assembly is set against a wall with all operating access from the front. Branch devices are typically molded-case circuit breakers (MCCBs), insulated-case circuit breakers (ICCBs), or fusible switches, and they are bolted in place rather than racked. The main device is usually a fused switch or a fixed-mounted MCCB or ICCB, though larger switchboards may use a fixed-mounted air-frame breaker. Copper or aluminum bus runs vertically and horizontally through the lineup, with deadfront barriers protecting operators from energized parts during normal operation.

Switchboards are the workhorse distribution equipment of commercial buildings, retail centers, mixed-use developments, multi-tenant buildings, and light industrial facilities, anywhere the available fault current sits comfortably below 100 kA, the load profile tolerates de-energization for breaker maintenance, and selective coordination is not code-mandated.

Two practical recognition cues: if the assembly sits flat against a wall with front access only, it is almost certainly a switchboard; and if the branch breakers are bolted in rather than racked on rails, it is a switchboard.

What Is Switchgear (Low-Voltage, UL 1558)

Low-voltage switchgear is a metal-enclosed assembly of switching, protection, and control equipment built to higher construction, testing, and maintainability standards than a switchboard. It uses drawout low-voltage power circuit breakers (LVPCBs, commonly called air-frame breakers) and is engineered for service-entrance duty in industrial plants, utility substations, generator paralleling lineups, and mission-critical distribution where fault current, reliability, and serviceability under load all push beyond what a switchboard is designed to handle.

The governing standards are NEMA SG-5 (*Power Switchgear Assemblies*), UL 1558 (*Metal-Enclosed Low-Voltage Power Circuit Breaker Switchgear*), and IEEE C37.20.1 (*Metal-Enclosed Low-Voltage Power Circuit Breaker Switchgear*). Access is provided from both the front and the rear, with a dedicated rear aisle in most installations. The interior is compartmentalized: bus, breaker cell, cable compartment, and instrument compartment are physically separated by metal barriers so that a fault in one compartment is contained from the others. Drawout breakers can be racked between connected, test, and disconnected positions, which means a breaker can be isolated and serviced while the rest of the bus remains energized. Common LVPCB families include the Eaton Magnum DS, ABB Emax 2, Schneider Masterpact, and GE EntelliGuard.

A defining electrical attribute is the short-time withstand rating, typically 30 cycles, which means the bus and breakers can carry the full available fault current long enough for a downstream protective device to clear the fault first. That single capability is what makes selective coordination practical on switchgear and impractical on most switchboards.

Switchgear is found in industrial process and manufacturing plants, utility station-service applications, hospitals, data centers, telecom central offices, and generator paralleling systems. Recognition cues: aisle access on both front and rear, breakers that rack out on rails, and a nameplate that reads UL 1558 or IEEE C37.20.1.

Medium-Voltage Switchgear (in Brief)

Most readers searching for a switchboard-versus-switchgear comparison are asking about low-voltage equipment, but the medium-voltage picture rounds out the answer. There is no medium-voltage switchboard category, at 5 kV and above, every assembly is some form of switchgear or specialty equipment.

Two MV families dominate. Metal-clad switchgear (IEEE C37.20.2) covers 5–15 kV, with 27 kV and 38 kV designs available, and uses drawout vacuum circuit breakers (VCBs) or, less commonly today, SF6 interrupters. Compartmentalization is complete: grounded metal barriers separate the bus, breaker, cable, and instrument compartments, and primary disconnect contacts are isolated by automatic shutters when the breaker is racked out. Metal-enclosed interrupter switchgear (IEEE C37.20.3) covers a similar voltage range but uses load-interrupter switches with power fuses instead of breakers; it is smaller and less expensive than metal-clad, with proportionally limited capability. Outdoor variants include pad-mounted gear and station-class gear for utility yard applications.

Key Differences Engineers Actually Care About

The table above gives the shape of the difference. The five distinctions below are where engineers verify whether an article actually understands the equipment.

Short-Circuit Withstand and Interrupting Ratings

Switchboards are rated for short-circuit *interrupting*, the device must clear the fault current the moment it sees it. Interrupting ratings up to roughly 100 kA at 480 V are available, but the assembly typically carries no published short-time withstand rating. Low-voltage switchgear is rated for both interrupting (commonly 65–200 kA) *and* short-time withstand, typically 30 cycles, meaning the bus and breakers can hold the full fault current for half a second while a downstream device clears it. That withstand rating is what enables intentional time delay in the trip curve without sacrificing the assembly.

Selective Coordination

Switchboards typically rely on instantaneous-trip MCCBs and ICCBs whose trip curves overlap during high-fault events; an upstream main and a downstream branch can trip together, dropping unrelated load. Switchgear with drawout LVPCBs and short-time-delay protection can be coordinated so that only the breaker closest to the fault opens. This matters wherever code mandates selective coordination, including NEC 700.28 (emergency systems), NEC 701.27 (legally required standby), NEC 708.54 (Critical Operations Power Systems), and NEC 620.62 (elevators).

Maintainability Under Load

A switchboard's fixed-mounted breakers require de-energization of the section for replacement, inspection, or secondary-injection testing. A switchgear breaker can be racked to test position, primary disconnects open, control power available, exercised and tested, then withdrawn entirely from the cell, all with the bus still energized and adjacent breakers still serving load. NFPA 70E energized-work procedures still apply, but the assembly is built to make those procedures feasible rather than exceptional.

Arc Flash and Containment

Switchgear can be specified as arc-resistant under IEEE C37.20.7, with accessibility types (1, 2, 2B, 2C) describing which sides of the assembly are protected against an internal arcing fault. Arc-resistant designs include reinforced enclosures, latching mechanisms, and vented plenums that direct arc gases and pressure away from operators. UL 891 has no equivalent arc-resistant classification for switchboards. For facilities working through an arc flash mitigation program, this difference often drives the equipment selection at the service entrance.

Production Testing vs Design Testing

Every switchboard receives production tests, hi-pot, mechanical operation, dielectric, on the individual unit shipped. Switchgear receives the same production tests plus design tests on representative samples, including full short-circuit current tests, mechanical endurance cycles, and temperature-rise verification. Design tests are not repeated on each shipment, but the family must have passed them for the assembly to be listed.

When Code Effectively Requires Switchgear

The NEC does not use the words "switchboard" or "switchgear" to mandate one over the other. Instead, it imposes performance requirements, chiefly selective coordination and adequate interrupting capacity, that are difficult or impossible to meet with a switchboard at any meaningful scale. The articles below are the ones engineers cite most often.

Selective coordination is required for:

• NEC 700.28, emergency systems, including life-safety branches in healthcare facilities.
• NEC 701.27, legally required standby systems.
• NEC 708.54, Critical Operations Power Systems (COPS), including designated critical infrastructure.
• NEC 620.62, elevator feeders, where uncoordinated tripping can strand passengers.

Beyond coordination, two other situations push the design toward switchgear. First, available fault current above switchboard interrupting ratings, wherever the calculated fault duty at the equipment exceeds the listed switchboard rating, switchgear or current-limiting upstream protection becomes necessary. Second, service-entrance applications above roughly 4,000 amps, switchboards are commercially available above that threshold, but practical bus and breaker limits push most large services to switchgear. Generator paralleling is its own category: a paralleling lineup is a specialized switchgear configuration with synchronizing controls, and switchboards are not used. See What Is Paralleling Switchgear for the full architecture.

The choice between switchboard and switchgear should be made early in power distribution design, informed by the short-circuit study, the coordination study, and the facility's operational profile.

Common questions

Next Steps

For most commercial buildings, a properly specified switchboard is the right answer; for industrial, utility, and mission-critical facilities, the combination of fault duty, selective coordination, and maintainability typically points to switchgear. If you are evaluating an existing lineup for modernization or scoping new equipment for a critical facility, see ControlCom's paralleling switchgear and switchgear retrofit approach.

Key takeaways

• A switchboard is built to UL 891 and NEMA PB 2 with fixed-mounted branch devices, front-only access, and interrupting ratings up to roughly 100 kA at 480 V.
• Low-voltage switchgear is built to UL 1558 and IEEE C37.20.1 with drawout circuit breakers, front and rear access, interrupting ratings typically 65 to 200 kA, and a short-time withstand rating (typically 30 cycles) that supports selective coordination.
• For equivalent ampacity, switchgear typically costs two to four times the installed cost of a switchboard due to design tests, drawout mechanisms, rear-aisle access, and higher fault ratings.
• NEC Articles 700.28 (emergency systems), 701.27 (legally required standby), 708.54 (Critical Operations Power Systems), and 620.62 (elevators) require selective coordination, which is generally impractical to achieve with a switchboard.
• At medium voltage (5 kV and above) there is no switchboard category: metal-clad switchgear is built to IEEE C37.20.2 and metal-enclosed interrupter switchgear to IEEE C37.20.3.