To an apprentice, “Switchboard” and “Switchgear” sound the same: just two different words for the “big metal box with all the Leistungsschalter.”
To a professional, this is the difference between a House Cat und eine Tiger.
Confusing them can be an expensive—or even fatal—mistake.
The common “rookie” answer is that “Switchgear is for high voltage, and Switchboard is for low voltage.”
Dies ist der #1 myth in power distribution.
While partially true (high-voltage ist always switchgear), it’s a dangerously incomplete answer because “Low Voltage Switchgear” absolutely exists.
So, what’s the real difference? It’s not voltage. It’s the Design Philosophy, which is dictated by two completely different UL standards.
- Switchboard: Built to UL 891. Designed for Verteilung.
- Switchgear: Built to UL 1558. Designed for Survival.
This distinction dictates everything: cost, safety, and (most importantly) how you maintain es.
The “Golden Insight”: “Fixed” vs. “Draw-out”
This is the “master-level” difference. It’s not what the “box” tut; it’s how the breakers come out.
1. Switchboard (UL 891) = “Fixed” (Bolted-in)
A switchboard is designed to be a “distribution” hub. Its philosophy is “install it and leave it.”
The breakers (typically Moulded Case Circuit Breakers, or MCCBs) are “Fixed”—they are physically bolted directly onto the main bus bar.
This is simple and (relatively) cheap.
But what if a 400A breaker fails? To replace it, you have no choice but to de-energize the entire switchboard. You must kill the main feed, work in the dark, unbolt the failed breaker from the bus bar, bolt the new one in, and then re-energize.
It’s a 4-hour, building-wide shutdown. It is nicht designed for maintenance.
2. Switchgear (UL 1558) = “Draw-out” (The “Drawer”)
A switchgear is a “protection and control system.” Its philosophy is “it must be maintainable, and it must not fail.”
The breakers (typically “Air Circuit Breakers” or ACBs) are “Draw-out.” They are built into a heavy-duty “drawer” or “trolley” system.
Why is this 10x more expensive? Because it’s a marvel of engineering. A technician can (in full Arc Flash PPE) open the cabinet door, attach a “racking” handle, and safely “draw out” the breaker from the live bus bar.
The breaker slides out on rails, and mechanical “shutters” automatically cover the live bus stabs. You pull the “drawer” out, swap it with a spare, and “rack” the new one in.
The data center, hospital ICU, or factory line never even flickered. You’re paying for uptime.
The “Plasma Fireball”: A Tale of Two Safety Philosophies
This “Fixed” vs. “Draw-out” design points to a deeper, critical difference in safety philosophy.
Switchboard: The “Open Room”
A Switchboard (UL 891) is basically an “open room.” The breakers, bus bars, and cable lugs are all in one shared, open metal box.
The “Horror Story”: An apprentice is torqueing a new 400A breaker onto the live bus bar (which he shouldn’t be doing). His wrench slips.
BOOM.
The wrench shorts the main bus bar, initiating a catastrophic Arc Flash—a “plasma fireball” that vaporizes the wrench and destroys the entire switchboard. The “open room” design means the fire spreads instantly, taking every breaker down with it.
Switchgear: The “Blast-Proof Bunker”
A Switchgear (UL 1558) is built on a philosophy of “Compartmentalization.”
It’s not an “open room”; it’s a series of “blast-proof bunkers.”
- The Main Bus Bar is in its eigenen separate, metal-enclosed “bunker.”
- Each “Draw-out” breaker is in its own metal-enclosed “bunker.”
- The control wiring (24V) is in its own separate, metal-enclosed “bunker.”
The (Same) “Horror Story”: A technician is “racking out” a breaker. The breaker itself fails and explodes.
The Result: The explosion is contained to that one “bunker.” The heavy steel walls protect the main bus bar and the other breakers from the blast. The rest of the facility stays online. You’ve lost one breaker, not the entire building.
Conclusion: “Cat” vs. “Tiger” (When to Use Which)
So, yes, a Switchboard and a Switchgear are both “big metal boxes with breakers.” But one is a House Cat, and one is a Tiger.
You use a Switchboard (UL 891 “Fixed”) when:
- Kosten is the primary driver.
- Uptime ist nicht critical (a full-building shutdown for 4 hours is “acceptable” for maintenance).
- Your application is “distribution” (e.g., a standard apartment building, a strip mall).
You use a Switchgear (UL 1558 “Draw-out”) when:
- Uptime und Sicherheit sind non-negotiable.
- The cost of a shutdown ($1M/hour) is infinitely higher than the cost of the equipment.
- Your application is “critical infrastructure” (e.g., a Hospital, a Datenzentrum, a Fabrik, or a Power Plant).
At VIOX, we manufacture the components (like MCCBs and ACBs) that go into beide systems. But as a Senior Application Engineer, my advice is simple:
Don’t buy a “Switchboard” when you really need a “Switchgear.” It’s not “saving money”—it’s a critical engineering mistake.
Browse our full line of UL 891 (Fixed) and UL 1558 (Draw-out) compatible circuit breakers, and design your system for the right level of safety and survival.
Technische Genauigkeit Hinweis
**Standards & Sources Referenced**
- This article is based on the key design differences between **UL 891** (Standard for Switchboards) and **UL 1558** (Standard for Metal-Enclosed Low-Voltage Power Circuit Breaker Switchgear).
- The terms "Fixed" (bolted-in) and "Draw-out" are standard industry and NEMA/ANSI terminology for these two types of construction.
- "Compartmentalization" is a key design and safety feature of UL 1558 switchgear, specifically designed to mitigate arc flash propagation.
**Timeliness Statement**
All technical principles and UL standards referenced are accurate as of November 2025.
