Switchgear is the heavy-duty equipment at the head of a building's electrical system that receives power from the utility service and splits it into feeders, with circuit breakers that can switch, isolate and protect each one. In everyday conversation people use "switchgear" for any large piece of service equipment, but strictly it is the most robust of three families: panelboards, switchboards and switchgear, each built and tested to its own standard.
The difference matters to an owner or a general contractor for three practical reasons. It changes what the equipment costs, how long it takes to arrive, and how much room and maintenance it needs for the next few decades. This guide explains the three in plain terms, then covers when a building needs which, and the South Florida problems that come with putting any of them in the wrong place.
The short version
Think of power flowing downhill. The utility delivers it to the service. The service equipment, which might be a switchboard or switchgear, divides it into large feeders. The feeders run to panelboards, and the panelboards divide it again into the branch circuits that feed lights, receptacles and equipment. A small shop may have only a meter and one panelboard. A large building has all three levels.
Panelboards
A panelboard is the familiar breaker panel: a cabinet, usually wall-mounted and accessible from the front, holding the breakers for branch circuits and smaller feeders. In the United States they are built to UL 67, the standard for panelboards used under the National Electrical Code. Every commercial space has at least one; a restaurant or medical office often has several, including dedicated panels for kitchen or imaging equipment.
Most tenant improvement electrical work happens at this level: a new panel for the suite, new circuits, and a clean panel schedule at the end. Adding a panel is a modest job. Running out of capacity upstream of it is not, which is where the next two families come in.
Switchboards
A switchboard is a freestanding assembly of sections that stands on the floor, usually at the service entrance, and feeds large branch feeders to panels, mechanical equipment and meter stacks. Switchboards are built to UL 891, which covers dead-front switchboards rated 1,000 volts or less. Most mid-size commercial buildings in South Florida, from strip centers to office buildings and mid-rise condos, are served by a switchboard, often with a utility metering section and a bank of tenant meters.
A switchboard can often be serviced from the front, and its breakers are commonly molded-case or insulated-case types. It is the practical workhorse: robust, compact enough for a normal electric room, and far simpler than true switchgear.
Low-voltage switchgear
Low-voltage power circuit breaker switchgear is a step up in construction. UL 1558 covers metal-enclosed assemblies rated 1,000 volts ac or less, containing low-voltage power circuit breakers and associated switching, metering and protective devices, and it is used together with IEEE C37.20.1. In practice that means compartments separating breakers and bus, power circuit breakers that usually draw out on rails for testing or replacement, and equipment designed to be maintained with the rest of the lineup kept in service.
Buildings that cannot tolerate a long outage, or that carry very large loads, tend to justify switchgear: hospitals and surgery centers, data rooms, large industrial plants, and big campuses. Above low voltage there is also medium-voltage switchgear, used where a facility takes service at the utility's distribution voltage and owns its own transformers. That is a different class of project again.
Side by side
| Panelboard | Switchboard | LV switchgear | |
|---|---|---|---|
| Standard | UL 67 | UL 891 | UL 1558 with IEEE C37.20.1 |
| Typical job | Branch circuits and small feeders | Service entrance and feeders | Service entrance and feeders where uptime and maintainability matter most |
| Mounting and access | Wall-mounted, front access | Floor-standing, often front access | Floor-standing, compartmented, often rear access |
| Breakers | Plug-on or bolt-on | Molded-case or insulated-case, usually fixed | Power circuit breakers, usually drawout |
| Where you see it | Every suite and floor | Most commercial and multifamily services | Hospitals, data rooms, industrial and large campuses |
Which one does your building need?
The engineer of record makes that call, based on the load calculation, the utility's service voltage, the available fault current and the owner's tolerance for outages. The questions that drive it are worth knowing so you can follow the conversation:
- How big is the load, and is it three-phase? Most commercial services are, and our guide to three-phase power explains why.
- How many meters? A multi-tenant building usually needs a switchboard with a meter section for each tenant, arranged the way the utility requires.
- What happens if it has to be shut down? If the answer is "patients, product or servers are at risk", drawout switchgear and a second source start to earn their cost.
- Where can it physically go? Size, working space and access for replacement all count. Equipment that cannot be removed without cutting a wall is a problem in 20 years.
For most tenant spaces and small buildings, the answer is simply a panelboard fed from the landlord's existing switchboard, and the real question is whether that switchboard has capacity left. If it does not, the project has become a service upgrade, and that is a different conversation.
Why lead times are long
Panelboards are often available from stock or close to it. Switchboards and switchgear usually are not, because each lineup is engineered to order for one building. The sequence adds up:
- The engineer finalizes the design, including ratings for bus, breakers and fault current.
- The manufacturer produces shop drawings, which go through submittal review with the engineer and, for metering sections, the utility.
- Only after approval does the order enter the factory queue, which varies with demand across the whole industry.
- Changes after release, such as a larger main or another tenant meter, can send the drawings back through review.
Nobody can promise a lead time months ahead, so the practical rule is to settle the service design early and release the equipment as soon as the drawings are approved. On a new building or a major renovation, the service equipment and the utility's transformer are often the items that set the energization date, not the wiring.
South Florida location problems
Flood elevation
Service equipment is expensive to replace and the whole building depends on it, so it should not sit where water can reach it. FEMA's guidance on building electrical systems classes meters, service and distribution equipment and panelboards as primary components and says protecting them is usually best done by elevating in place or relocating to an upper floor. In a flood zone, the elevation required is set by the building department and the flood maps, and the design should confirm it before the electric room is drawn at grade.
Salt air and humidity
Near the coast, corrosion attacks enclosures, bus and terminations, and it is one of the conditions Miami-Dade's recertification inspections look for (see the electrical side of the 40-year recertification). Outdoor equipment needs an enclosure suited to the location, and indoor rooms need to stay dry and conditioned. An electric room that doubles as a storage closet with the door propped open is a common way to age equipment early.
Hurricane season
Planned shutdowns for tie-ins, replacements or maintenance are easier to schedule outside the peak of the season, and after a storm the equipment should be checked before it is re-energized if water or debris got near it.
Maintenance is part of owning it
NFPA 70B, now published as the Standard for Electrical Equipment Maintenance (earlier editions were a recommended practice), sets out how electrical maintenance programs should be run. Whatever applies to your building, the basics are the same: keep the room clean and clear, scan the equipment with infrared under load to find hot connections, check and tighten terminations, exercise breakers, and keep records. Drawout switchgear makes this easier; a switchboard with no maintenance history makes it harder. Our preventive maintenance work covers the routine side, and the findings tell you when a repair is due before it becomes an outage.
Planning a new service or a replacement?
KRW Electric (EC13012832) handles commercial service upgrades, switchboards and switchgear across Miami-Dade, Broward and Palm Beach, working with the engineer of record and the utility from design through energization. Send us the drawings or a photo of the existing equipment and its label, or call (305) 359-7312, and we will tell you what you have and what the next step looks like.
Reviewed by Kyle White, KRW Electric Company LLC — licensed electrical contractor EC13012832.
