Install Multiple ZEFNET Enabled Chargers on a Single Breaker Using Load Balancing

Installing multiple ZEFNET enabled chargers on a single breaker with load balancing is an efficient way to maximize your electrical infrastructure. This guide will help you through the process, ensuring that all chargers operate effectively without overloading your circuit. This guide is intended for charger owners, installers, or those executing a residential utility program on behalf of a utility.

Warning: This installation should only be undertaken by professional electricians. Improper installation and/or configuration can result in electrical hazards, equipment damage, or personal injury.

Materials Needed:

• Junction Box
• Double Pole Breaker (40A/50A/60A/80A/100A depending on your setup)
• ZEFNET enabled EVSEs (provided with lag bolts, spacers, plug socket, and attachment screws)
• Appropriate wiring and tools for electrical installation

Power Requirements:

• 208V or 240V - L1 + L2 + Ground
• Ensure proper grounding and labeling of wires

Step-by-Step Installation Guide

1. Prepare the Installation Site

• Locate a suitable installation site for the chargers, ensuring there is enough space and accessibility for wiring and usage.
• Install a junction box near the chargers if one is not already present.

2. Wiring the Breaker

• Install a double pole breaker in your main breaker panel. The rating (40A, 50A, etc.) depends on your total load requirements.
• Ensure you use appropriate wire gauges for the load capacity. Typically, for a 40A breaker, you would use 8 AWG wire.
• Important: The breaker size must not exceed the continuous use rating of the lowest power rated charger. For instance, if a 40A and 60A rated charger are on the same breaker, a 40A breaker must be used.

3. Connecting the Chargers

• Service Connections: Connect L1, L2, and Ground from your main circuit breaker panel to the junction box. Ensure the service transformer secondary connection is properly identified and labeled.
• Only connect the two phases (L1 and L2) and Ground to the ZEFNET HCS charger inputs. Do not use the Neutral for the charger as it's a single-phase device.

4. Load Balancing Setup

• ZEFNET chargers support load balancing, allowing up to four chargers to share a single circuit without exceeding the breaker capacity.
• Use the ZEFNET cloud platform to configure load balancing. Each charger must be registered and linked to the same breaker.
• Access the ZEFNET portal and navigate to the device management section. Add all chargers and configure them to share the load. This ensures that if all chargers are used simultaneously, the total current draw does not exceed the breaker rating.
• Recommended: For best balancing outcomes, use chargers with the same power output on a single circuit.
• Critical: The correct software settings within ZEFNET must be set before use, otherwise damage can occur to wiring and the chargers.

5. Testing and Verification

• Once wired and configured, turn on the breakers and power up the chargers.
• Test each charger individually and then together to ensure load balancing is functioning correctly.
• Verify that the load is balanced as per the settings and no circuit is overloaded.

Additional Tips:

• Grounding: Ensure the Ground at the service panel is properly connected to enable ground-fault protection.
• Safety: Always follow local electrical codes and safety standards. Use a professional electrician if you are unsure about any steps.

Load Balancing Example for Two Chargers

When balancing against a 50A breaker (40A actual continuous output), the system will issue commands to each charger to run at 50% of 40A each, which is 20A, when they are both requesting power. The chargers ramp up and down at 25% increments.

• An 11.5kW (48A actual output) charger will be issued a command to run at 20A, but the closest it can get (without going over the 20A limit) is 12A.
• A 7.7kW (32A actual output) charger will be issued a command to run at 20A, but the closest it can get (without going over the 20A limit) is 16A.

In this situation, a 7.7kW charger could not be used in the circuit, without changing the breaker to 40A, because you are required to defend the lowest powered charger from overcurrent.  A 50A breaker running a device which needs to be defended by a 40A breaker is not acceptable.

If you didn’t want to change any electrical infrastructure, two 11.5kW units would need to be used. Both chargers will only run at 12A when both are running simultaneously.

This example demonstrates why a professional electrician should be consulted to ensure the correct configuration is determined.
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By following these steps, you can efficiently set up multiple ZEFNET enabled chargers on a single breaker, utilizing load balancing to optimize your electrical infrastructure.

For more detailed instructions and troubleshooting, you can refer to the ZEFNET EVSE Wiring Guide and the Installation and Owners Guide on the ZEF Energy support site.