Okay, let's break this down. You're essentially asking if you can skip switchgear in your electrical service upgrade, placing your step-up transformer and 800A panel directly after the utility transformer, meter, and a disconnecting means.

The short answer is: It's possible, but highly dependent on several factors, and likely not the best or most practical solution for many situations, especially considering cost and long term service and replacement.

Here's a more detailed explanation

Factors to Consider:

1. Utility Requirements



This is the MOST IMPORTANT factor. Utilities have very specific requirements about metering, disconnects, and protection. They may require switchgear, or at least a specific type of disconnect, for their own safety and grid stability. You MUST get their approval for this design. They might specify the type of disconnect needed, its location, and how it should be accessible. They may also have requirements for fault current coordination and protection of their transformer.2. National Electrical Code (NEC) and Local Codes

The NEC will dictate many aspects of your installation, including:

Overcurrent Protection

You must have overcurrent protection devices (fuses or circuit breakers) rated to protect the transformer and downstream equipment. Where these are located is critical.

Disconnecting Means

As you mentioned, a readily accessible disconnecting means must be provided to isolate the service. The NEC has specific requirements for the type and location of this disconnect.

Grounding and Bonding

Proper grounding and bonding are essential for safety and to prevent electrical shock.

Working Space

Sufficient working space must be provided around electrical equipment. Local codes may have additional or more stringent requirements than the NEC.3.

Transformer Size and Fault Current

The size of the utility transformer and your step-up transformer will determine the available fault current at your 800A panel. High fault current can damage equipment if not properly protected against. Switchgear is often used in situations with high fault current because it is specifically designed to handle it and provides more robust protection. (High interrupting rating). If the available fault current is low enough, and your 800A panel and other equipment are properly rated, you might be able to avoid switchgear.4.

Step-Up Transformer Characteristics

The step-up transformer will need its own overcurrent protection on both the primary (low-voltage) and secondary (high-voltage) sides. The inrush current of the step-up transformer can also be significant. The overcurrent protection must be able to handle this inrush without nuisance tripping.5.

Maintenance and Future Expansion

Switchgear provides a more organized and easily maintainable system. It allows for easier isolation of different parts of the system for maintenance or repairs. If you anticipate future expansion, switchgear can often be more easily expanded than a simpler system.6.

Cost vs. Functionality and Reliability

While eliminating switchgear may seem cheaper upfront, consider the long-term costs. Switchgear is designed for high reliability and long service life. Using cheaper components may result in more frequent maintenance and repairs. Consider the cost of downtime if something fails.

Why Switchgear is Often Used



Higher Interrupting Rating

Switchgear is designed to handle much higher fault currents than standard panels.

Coordination and Selectivity

Switchgear allows for better coordination of overcurrent devices, ensuring that only the affected part of the system is shut down during a fault.

Monitoring and Control

Modern switchgear often includes advanced monitoring and control features.

Compartmentalization

Switchgear compartmentalizes different components of the electrical system, improving safety and maintainability.

Ease of Maintenance

Switchgear is designed for easier access and maintenance.

Arc Flash Mitigation

Some switchgear designs incorporate features to mitigate the risk of arc flash.

Possible Scenario Where It Might Work (But Still Needs Thorough Review)

Let's say you have a relatively small utility transformer, a small step-up transformer, and a low available fault current. In this hypothetical scenario, you might be able to do something like this:1.

Utility Transformer2. Utility Meter3. Utility-Approved Disconnect

This might be a fused disconnect switch rated for the available fault current.4.

Primary Overcurrent Protection for Step-Up Transformer

Fuses or a circuit breaker sized to protect the step-up transformer.5.

Step-Up Transformer6. Secondary Overcurrent Protection for Step-Up Transformer

Fuses or a circuit breaker sized to protect the step-up transformer.7.

800A Panel

With a main breaker or main fuses rated for the available fault current.

Important Considerations for This Scenario



Fault Current Study

A thorough fault current study is essential to determine the available fault current at each point in the system.

Coordination Study

A coordination study is needed to ensure that the overcurrent devices are properly coordinated.

Equipment Ratings

All equipment (disconnects, fuses, circuit breakers, panels) must be rated for the available fault current.

Utility Approval

You must get the utility's approval for this design.

Recommendations


Consult with a Qualified Electrical Engineer

Don't try to design this yourself without expert help. A qualified electrical engineer can perform the necessary calculations, studies, and coordination to ensure a safe and reliable system.2.

Contact the Utility Early

Discuss your proposed design with the utility as early as possible to get their feedback and requirements.3.

Evaluate the Long-Term Costs

Consider the long-term costs of maintenance, repairs, and potential downtime when comparing different design options.

In summary, while technically* possible in some limited situations to eliminate switchgear, it's generally not recommended unless you have a very specific set of circumstances, low fault current, and a strong understanding of the trade-offs. It's crucial to prioritize safety, reliability, and compliance with all applicable codes and regulations. Consult with a qualified electrical engineer and the utility to determine the best solution for your specific needs.

Good luck! Flag for review