In NYC, the requirement for a ventilation fan serving network compartments in a 460V service scenario can be a bit nuanced. Here's a breakdown of the code considerations and best practices

NYC Electrical Code (Based on NEC with Amendments):
NEC 230.71(B)(1) Number of Services. This is the foundational rule that allows for more than one service to a building if needed for fire pumps and emergency systems. NEC 230.2(A) One Building or Other Structure Not to Be Supplied by More Than One Service. This is the general rule that would prohibit more than one service. It refers to the entire building, not just the network compartment. NEC 225.30-39- Outside Branch Circuits and Feeders. There are additional rules on outside branch circuits and feeders (e.g. for separate buildings). Emergency Systems and Critical Operations Power Systems (COPS). If the ventilation is deemed essential for these systems, then you need to follow these guidelines.

So, can the ventilation fan be on the load side?

Generally, yes, it can be connected to a breaker/fuses on the load side of the service equipment unless there's a specific reason necessitating a separate service switch.

Reasons why it Might need a Separate Service Switch (Less Likely, but Always Check)


Emergency System/COPS requirements if the fan is absolutely critical for a system that requires a generator to support life safety loads.2. Separate Feeder NEC article 225.30 mentions that for a single building, only one feeder/branch circuit is allowed.
3. Local Inspector Interpretation

In NYC, the interpretation of the code by the local electrical inspector holds significant weight. If they deem the ventilation as an essential system that needs absolute reliability, they might require a separate service switch.

Recommendations and Best Practices



Consult with a Licensed Electrical Engineer

This is crucial. A licensed engineer can assess the specific installation, code requirements, and any relevant NYC amendments. They can then provide a design that is code-compliant and meets the needs of the facility.

Submit Plans for Approval

NYC requires electrical plans to be submitted to the Department of Buildings (DOB) for approval. This allows the DOB to review the design and ensure compliance with the code.

Clarify with the Utility Company

The utility company (Con Edison in most of NYC) may have specific requirements for connecting to their service. It's a good idea to clarify with them whether they have any preferences or requirements for the ventilation fan.

Consider Redundancy and Reliability

Even if not strictly required, consider the importance of the ventilation system. If its failure could lead to significant issues (e.g., overheating of critical equipment), it might be prudent to incorporate redundant power supplies or a generator backup, even if the main power comes from a breaker on the load side of the service equipment.*

Follow Good Engineering Practices

Ensure that the circuit breaker/fuse protecting the ventilation fan is properly sized and that the wiring is adequate for the load.

In summary, while technically the fan can often be connected to the load side, the best course of action is to consult with a qualified professional, submit plans for approval, and clarify with the utility company to ensure compliance and reliability. Flag for review