You're on the right track with 700.10(B)(5)(d). Let's break down what that means and apply it to your situation.

Understanding 700.10(B)(5)(d)

This section essentially allows you to have a common set of feeders (wires) between the emergency power source (your generator) and the point where you split the emergency and non-emergency loads. Think of it as a trunk line that then branches out.

Applying it to Your Setup

Yes, based on the code section you cited, you can go directly from a generator to a distribution panel that feeds both the emergency and optional standby transfer switches if the distribution panel meets specific requirements. Here's why and what you need to consider: Common Distribution Panel

The distribution panel becomes the "point where emergency loads are separated from all other loads." Think of it as a place where you decide how the generator power will be used for both Emergency and Optional Standby.

Emergency System Integrity

The primary concern is that the distribution panel and the wiring downstream from the emergency transfer switch must maintain the integrity and reliability of the emergency system.

Key Considerations and Requirements


Selective Coordination

You must ensure selective coordination of overcurrent protection devices (breakers, fuses) in the emergency system. This means that if a fault occurs in a branch circuit fed by the emergency panel, only the breaker/fuse protecting that circuit should trip, leaving the rest of the emergency system (and other essential loads) powered. A short in an outlet should not take down the entire emergency system.2.

Separation of Wiring Methods

The emergency system wiring after the distribution panel (i.e., to the emergency transfer switch and the loads it serves) needs to be physically separated or otherwise protected from the normal wiring.3.

Signage

The distribution panel should be clearly labeled to indicate that it serves emergency and optional standby loads.4.

Emergency Power System Transfer Equipment Placement

Make sure the placement of the transfer switches are in close proximity to the load the are dedicated to.

Why This is Allowed and Why It Matters Cost Savings

It can be more economical to run one larger set of feeders from the generator to a central distribution point than to run two separate sets of feeders.

Space Savings

It simplifies the overall electrical layout.

Important Notes



Local Codes

Always check with your local electrical inspector. Local codes may have stricter interpretations or additional requirements.

Professional Design

A qualified electrical engineer or experienced electrician is essential to design and install this type of system to ensure compliance with codes and proper operation. Selective coordination studies, load calculations, and proper labeling are critical.

In Summary

You can go directly from a generator to a distribution panel feeding two transfer switches (one for emergency and one for optional standby) provided you: Ensure selective coordination of overcurrent devices. Maintain physical separation or other protection of emergency system wiring. Properly label the distribution panel. Comply with all applicable codes and regulations. Engage a qualified professional for design and installation.Essentially, the distribution panel becomes a critical point where you split the power from the generator in a controlled and compliant way.Disclaimer: Always consult with a qualified and licensed electrical professional for your specific project.* Flag for review