Yes, you are permitted to bring a 277/480V feeder to the concession stand to feed a new panel for the tennis court lighting and electric heaters, subject to compliance with the National Electrical Code (NEC) and local codes. Here's a breakdown of the key considerations

NEC Considerations and Steps:

1. Feeder Sizing and Overcurrent Protection (Article 215 & 240)



Load Calculation

Perform a load calculation (NEC Article 220) to determine the total demand load of the tennis court lighting and electric heaters. Include factors like demand factors and any diversity factors that might apply. Overestimate to provide for future expansion.

Feeder Ampacity

Size the feeder conductors (wire gauge) based on 125% of the continuous portion of the calculated load plus 100% of the non-continuous load. Ensure the conductor insulation type is suitable for the environment (temperature rating, wet/dry location).

Overcurrent Protection

Select an appropriately sized overcurrent protective device (circuit breaker or fuses) for the feeder. The breaker/fuse rating should protect the feeder conductors and the downstream panel.2.

Voltage Drop (Informative Annex D)

Calculate the voltage drop from the 480V panel to the new panel in the concession stand, and then to the tennis court lights and heaters. Voltage drop should be kept to a minimum to ensure proper equipment operation and prevent premature failure. The NEC recommends a maximum voltage drop of 3% for feeders and 5% overall (feeder + branch circuit).3.

Grounding (Article 250)



Equipment Grounding Conductor (EGC)

Run an equipment grounding conductor (typically copper) with the feeder conductors. The size of the EGC is based on the overcurrent protection device for the feeder (Table 250.122). This conductor provides a low-impedance path for fault current to return to the source, allowing the overcurrent device to trip and clear the fault.

Separately Derived System (SDS) Considerations

If the new panel in the concession stand will serve as a separately derived system (meaning you are stepping the voltage down from 480V to 277V or 120V for some loads), additional grounding requirements apply (see below).4.

Wiring Methods (Chapter 3)

Choose an appropriate wiring method for the feeder run. Common options include:

Rigid Metal Conduit (RMC)

Provides excellent physical protection.

Intermediate Metal Conduit (IMC)

Lighter and less expensive than RMC, but still provides good protection.

Electrical Metallic Tubing (EMT)

Lighter and less expensive than RMC or IMC, but requires fittings designed for EMT.

Underground Feeder (UF) Cable

If the feeder will be buried, use UF cable or conduit with appropriate conductors. Pay attention to burial depth requirements (NEC Table 300.5). Ensure the wiring method is suitable for the environment (wet, dry, corrosive).5.

Disconnecting Means (Article 225 & 408)



Feeder Disconnect

Install a disconnecting means (circuit breaker or fused disconnect switch) at the origin of the feeder (at the 480V panel). This allows you to de-energize the entire feeder for maintenance or emergencies.

Panelboard Disconnect

The new panel in the concession stand must have a main disconnecting means (circuit breaker or switch) that can disconnect all the branch circuits.6.

Overcurrent Protection Location

Make sure the overcurrent protection for the feeder is at the supply end of the feeder and sized according to the ampacity of the feeder conductors.7.

New Panel in Concession Stand (Article 408)

Select a panelboard rated for the appropriate voltage (480V or whatever voltage you plan to distribute). Ensure the panelboard has sufficient space for the required circuit breakers. Properly label all circuit breakers in the panelboard.8.

Step-Down Transformer (If Necessary)



If you need 120V or 277V for any loads within the concession stand (outlets, lighting, etc.), you will need to install a step-down transformer in the new panel. Separately Derived System (SDS) Grounding (NEC 250.30)

When using a transformer to create a 120V or 277V system, you are creating a Separately Derived System (SDS). You MUST bond the X0 (neutral) terminal of the transformer to ground at the location of the transformer. This creates a new grounded conductor (neutral) for the 120/277V system. The size of the grounding electrode conductor (GEC) for the SDS is based on the size of the transformer's secondary conductors (NEC 250.66). The GEC must connect to a grounding electrode (typically a ground rod or the building steel).

Overcurrent protection is crucial on both the primary and secondary sides of the transformer. Size these devices properly to protect the transformer windings.9. Coordination of Overcurrent Protective Devices (240.12)

Consider the coordination of the overcurrent devices (breaker/fuse) at the origin of the feeder, at the panel, and on branch circuits. The goal is to ensure that the smallest overcurrent device closest to the fault trips first, minimizing the impact of a fault.10.

Labeling (110.21, 408.4)

Clearly label the feeder disconnect at the 480V panel and the new panel in the concession stand. Label all circuit breakers in both panels. If a transformer is installed, label it with its voltage, kVA rating, and other relevant information.11.

Permitting and Inspection

Obtain the necessary electrical permits from your local building department. Schedule an inspection by a qualified electrical inspector to ensure that the installation complies with the NEC and local codes.

Important Considerations



Coordination with the Athletic Complex

Before making any connections to the 480V panel, coordinate with the facility manager or electrical contractor responsible for the athletic complex's electrical system. Ensure that the existing panel has sufficient capacity to handle the additional load. They may need to perform a load study on the 480V service.

Qualified Personnel

This type of electrical work requires the expertise of a qualified and licensed electrician. Do not attempt to perform this work yourself unless you are properly trained and licensed.

Safety

Work safely and always de-energize circuits before working on them. Use appropriate personal protective equipment (PPE). Lockout/Tagout procedures are essential.

Future Expansion

Consider the potential for future expansion when sizing the feeder and panel. It's often more cost-effective to install a slightly larger feeder and panel initially than to have to upgrade later.

Accessibility

Ensure that the new panel and any disconnect switches are readily accessible.

Local Codes

Always check with your local building department for any additional requirements or amendments to the NEC. Local codes may be more stringent than the NEC.

In summary: Yes, bringing a 277/480V feeder is a viable option. You must adhere to all applicable codes (NEC and local) and involve a qualified electrician to ensure a safe and compliant installation. The load calculation, proper grounding, and voltage drop calculations are critical for the project's success. Good luck! Flag for review