Key Considerations When Specifying An Electrical Switchboard for a Project

When you’re specifying an electrical switchboard for a project, there’s a lot to think about. A well-designed switchboard keeps your electrical system running safely and efficiently, while a poorly specified one can lead to downtime, compliance issues, or costly retrofits down the line.

Whether you’re working on an industrial facility, a commercial building, or a large-scale distribution project, getting the details right is critical. This guide breaks down everything you need to know about specifying switchboards for a project so you can make informed, quality decisions.

Review Your Project Requirements Before Specifying a Switchboard

Not all electrical switchboards are the same, and choosing the wrong one can create serious headaches down the road. This is why the first thing you need to do is take a step back and analyze what your project actually needs. 

Understand Your Application

The first question is: What type of facility are you working on? Different applications have different electrical demands, and the type of switchboard required depends on the nature of the electrical loads it will support. 

For example, commercial buildings such as office spaces and retail stores typically use 208V switchboards to accommodate lighting, HVAC systems, and office equipment. In contrast, industrial facilities that power heavy machinery often require higher-voltage switchboards, such as 480V or 600V, to handle large motor loads efficiently. Data centers, which prioritize reliability and redundancy, frequently opt for 800V switchboards to improve energy efficiency and reduce power losses over long distances.

Main vs. Distribution Switchboards

You need to be well aware that not all switchboards serve the same purpose. A main switchboard distributes electricity from the utility source to different parts of the facility, while distribution switchboards handle localized power distribution. Think of the main switchboard as the “Grand Central Station” of your power system and the distribution switchboards as the local stops.

In many commercial or institutional settings, you’ll have one main switchboard that serves multiple distribution boards across different areas of the building. Each distribution board manages power for a specific floor, section, or equipment cluster. Planning this layout in advance helps reduce installation costs and keeps maintenance straightforward.

Voltage Requirements

Voltage selection is another huge factor to keep in mind when specifying an electrical switchboard. Most commercial projects run on 480Y/277V to power big systems like HVAC units, EV chargers, and heavy machinery. When it's time to power smaller things—like lights, outlets, and appliances—they step it down to 208Y/120V.

In industrial settings, the voltage needs can go even higher. Manufacturing plants and large power systems often use 600V or even 800V switchboards to handle high-powered equipment. If you skip this step or choose the wrong voltage early on, you’ll probably run into compatibility issues later. It's one of those details that’s easy to overlook but hard to fix down the road.

Main Bus Amperage & Load Requirements

The main bus amperage refers to how much current your switchboard can handle. This needs to align with the total power demand of your project, typically measured in kilowatts (kW).

For example, if your project includes several high-power machines that require a total of 1500 kW, you’ll likely need a main switchboard rated for 2000A or higher. Specifying the right amperage from the start makes sure you won’t overload the system. Your engineer can perform a load calculation for your entire building and recommend an appropriate bus size. Don’t guess here—undersizing can lead to overheating, and oversizing can cost you more than necessary.

Check Relevant Codes and Standards For Electrical Switchboard Specifications

Safety is everything when it comes to electrical switchboards. You don’t want to install a system that doesn’t meet regulations. That could lead to delays, extra costs, or worse — serious electrical issues in the long term.

Local Utility Codes

Start by checking local codes. Different regions have different rules for metering, grounding, and short-circuit ratings. If your switchboard doesn’t comply, you might have to replace or modify it, which can be a costly headache. Some of the main local utility codes to keep in mind are:

• Metering provisions (to measure power usage)
  
  
• Fault current ratings (to handle short circuits safely)
  
  
• Specific grounding requirements
  
  

You may also need to coordinate with your utility provider during the design phase. They can confirm metering requirements, utility tie-ins, and short-circuit expectations before the equipment is ordered. Remember that standards vary both per state and country. The USA has adopted the NEC, but this is not enough information: you need to verify which version of the NEC your state is under.

UL Certification & Safety Standards

UL certification (Underwriters Laboratories) is one of the most widely recognized safety standards for electrical equipment. A UL-listed switchboard means it has been tested for fire resistance, electrical shock hazards, and performance reliability. This is why you need to look for certifications to make sure that the switchboard you choose meets the safety standards you need it to. 

For example, the (UL) certification confirms that it has been tested for fire resistance and electrical hazards. Other certifications, such as those from the American National Standards Institute (ANSI) or the International Electrotechnical Commission (IEC), may be required based on the project’s location. In industrial settings, the National Electrical Manufacturers Association (NEMA) provides ratings that specify whether a switchboard is suitable for indoor or outdoor environments.

If you are looking for even more specific certifications, you should take a look at:

• ANSI (American National Standards Institute): Used for industrial applications
  
  
• IEC (International Electrotechnical Commission): Required for global projects
  
  
• NEMA (National Electrical Manufacturers Association): Determines enclosure ratings (more on this later)

AIC Rating

AIC (Ampere Interrupting Capacity) tells you how much fault current your switchboard can safely interrupt.

​​You don’t just calculate AIC once and forget it. It starts with the source or utility, and then it gets re-calculated at every major connection point — from electrical switchboards to transformers, panel to panel, and so on. It’s all about making sure each piece of the system can handle what it’s connected to.

Several things can influence the calculated AIC:

• Type of Source: Whether you're working with a pad-mounted transformer, pole-mounted transformer, generator, battery, or utility vault, each one behaves differently. For example, pole-mounted transformers usually have lower impedance than pad-mounted ones, which means they allow more current to flow, resulting in a higher AIC.
• Transformer Specs: The kVA, impedance, and step-down voltage of utility transformers play a big role in the fault current.
• Generator and Battery Specs: The kW rating and voltage of your generators or batteries also matter. Smaller units usually produce lower fault currents.

Establish Electrical Switchboard Specifications

Once you’ve nailed down the basics, it’s time to define the technical specifications. This is where you decide what components go inside your switchboard.

Main Bus Amperage & Interrupting Capacity

The main bus is the heart of your switchboard. It carries the electrical current throughout the system, so its rating must match your needs. Typical sizes range from 400A to 4000A. If you choose a bus that's too small, it won't handle your power load. If it's too big, you’ll end up spending more money than necessary.

Interrupting capacity (AIC) is another key factor. It tells you how much fault current the rated breaker can withstand before it fails. For example, a 65kAIC rating means the switchboard can safely interrupt a short circuit of up to 65,000 amps. If your system operates in a high-fault environment, you might need a switchboard rated at 100kAIC or higher. This ensures protection against catastrophic failures. The AIC rating must be calculated based on the available fault current at the source or utility connection point. This value must then be re-evaluated at every downstream critical connection—such as from switchboard to transformer or panel to panel—because the fault current can change depending on wire length, impedance, and equipment. Getting this calculation right at every level helps you make sure that each component can safely interrupt fault currents at its location.

Main Case Circuit Breakers

Your electrical switchboard will need main circuit breakers (MCCBs) to control and protect the entire system. MCCBs are the go-to breakers for three-phase systems. You’ll find them in industrial, commercial, and even residential settings. They’re versatile, reliable, and built to handle different needs.

There are several types of MCCBs worth knowing about:

• Mission-Critical MCCBs – Used where uptime is essential.
• Motor Circuit Protectors (MCPs) – Designed specifically to protect motors.
• DC Circuit Breakers – For systems that run on direct current.

You don’t need to know every detail, but understanding that these different MCCBs exist helps you choose the right one for the job.

When and Why to Use Disconnect Switches

Disconnect switches do more than just isolate equipment. Yes, they’re used to cut off power entirely, but they can also act as a service entrance shutoff or be installed for local maintenance purposes. Here’s a real-world example: Contractors often install 30–60 amp non-fused disconnects next to rooftop HVAC units. That way, maintenance crews don’t have to go all the way back to the electrical room just to shut something off.

Whether you use a breaker or a disconnect often comes down to code requirements, project specs, or even personal preference.

Feeder Breakers & Protection Features

Feeder breakers distribute power from your main electrical switchboard to different areas of your facility. Choosing the right ones keeps your electrical system safe and efficient. The number and size of your breakers depend on your power needs. If they’re too small, circuits can overload. If they’re too large, you might waste energy and reduce protection.

How to Choose the Right Feeder Breakers

To set up a reliable system, focus on two key factors:

• Number of breakers: Count how many areas need their own power feeds. Each section with different electrical demands should have a separate breaker. This prevents one overloaded circuit from affecting the entire system.
  
  
• Amperage ratings: Match each breaker to the power demand of its section. If a breaker is too weak, it will trip frequently and disrupt operations. If it’s too strong, it may not respond properly to faults, increasing the risk of damage or fire.
  
  

Extra Protection for Safety and Reliability

Feeder breakers control power flow, but if you add extra safety features, you will improve fault detection, speed up response, and reduce the risk of system-wide failure. Consider adding:

• Surge protection: Shields your equipment from voltage spikes caused by lightning, power grid fluctuations, or sudden outages. Without it, sensitive electronics can fail, leading to expensive repairs and downtime.
• Arc flash protection: Reduces the risk of electrical explosions that can cause serious injuries (high-power systems are especially vulnerable, making this feature essential for worker safety). NEC 240.87, for example, is used for overcurrent devices of 1200A and over.
• GFCI Protection – Ground Fault Circuit Interrupters help protect people from electric shock, especially in wet or risky environments.

Metering & Remote Monitoring

A modern switchboard does more than just distribute power; it can also help you track energy usage and performance. Adding metering options gives you real-time insights into your system’s efficiency.

Every meter you install will come with Current Transformers (CTs) — that’s standard. What changes is the type of CT and its length. You’ll usually be working with either standard-grade CTs or revenue-grade CTs, depending on whether you just need basic monitoring or precise measurement for billing purposes.

In addition to CTs, meters may also require other accessories to get accurate readings or meet system requirements. These can include:

• Voltage Transformers (VTs) – Used to step down voltage for measurement.
  
• Potential Transformers (PTs) – Essentially the same as VTs, just a different naming convention depending on the context.

If you want to take it one step further, you can even consider smart metering solutions. These let you monitor energy consumption remotely, helping you optimize power distribution and cut down on waste. This is especially useful in large buildings where energy costs add up quickly.

Determine Physical Layout

A well-designed switchboard won’t help if it doesn’t fit your space. You need to plan carefully to make sure everything fits, stays accessible, and works safely.

Make Sure it Fits

Your switchboard must fit in your electrical room without blocking walkways or ventilation. Focus on these details:

• Number of sections: Measure the width, depth, and height of your space. Your switchboard needs to fit without crowding other equipment. A tight fit makes future maintenance harder.
  
• Cable entry and exit points: Plan where cables will go in and out. A clean setup makes installation easier and keeps maintenance simple. Poor routing can lead to tangled wires and harder repairs.
  
  

Pick the Right Enclosure

Your electrical switchboard needs protection from dust, moisture, and other hazards. NEMA ratings tell you how much protection each enclosure provides:

• NEMA 1: Standard for indoor use. Works well in most commercial buildings.
  
• NEMA 3R: Designed for outdoor use. Protects against rain and weather.
  
• NEMA 4X: Waterproof and corrosion-resistant, which makes it best for harsh or wet environments. NEMA 4X used for enclosures for switchboards are generally 316SS or 304SS.
  
  

Add Safety Features

Extra safety features help prevent accidents and protect your equipment:

• Kirk Key interlocks: Kirk Keys are mechanical interlocks that help you avoid accidentally switching between power sources. This keeps your system safe and helps prevent electrical faults. Unlike electrical interlocks—which you can control remotely using relays—Kirk Keys work manually. Manual transfer switches are also mechanical, like Kirk Keys. On the other hand, automatic transfer switches fall under electrical interlocks. Knowing the difference helps you choose the right setup to protect your equipment and keep things running smoothly.
  
• Insulated bus bars: Reduce the risk of short circuits and electrical failures.
  
• Lockable doors: Keep your switchboard secure and prevent unauthorized access.
  

Consider Switchboard Lead Time

Many projects run into delays because they don’t account for lead times. Custom switchboards, especially ones with specialized components, take time to manufacture. Some parts, like circuit breakers and protective relays, can have long wait times. If you don’t plan ahead, your entire project could be held up.

The best way to avoid this? Work closely with suppliers early in the process. Get a realistic timeline for manufacturing and delivery. Order critical components in advance to avoid last-minute scrambling. Being proactive keeps everything on schedule and prevents unnecessary stress.

Bottom Line: Work With the Right Electrical Switchboard Provider 

Choosing the right switchboard is all about matching specifications to your project needs, but it’s easy to overlook small details that can cause big problems later. That’s why working with an experienced supplier can make all the difference.

The right provider will help you optimize your design, ensure compliance, and source quality components without unnecessary delays. If you’re ready to move forward, talk to our sales team today, and let’s find the best switchboard solution for your project.

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