Materials

2 x Epo buttons with N/O and N/C contacts 1 x 5-terminal relay (preferably DPST) 1 x Diode Wire

Wiring Diagram



Step 1: Connect Epo Buttons Connect the N/O (Normally Open) contacts of both Epo buttons in parallel.

Step 2: Connect Relay Connect the N/O (Normally Open) contacts of the Epo buttons to the coil terminals of the relay. Connect the common terminals of both Epo buttons to the positive terminal of a 24VDC power supply.

Step 3: Connect HVAC Units Connect the trip contacts of the HVAC units to the terminals of the relay that are normally closed (NC) when the relay is de-energized.

Step 4: Connect GE Main Breaker Connect one black wire from the GE Main Breaker to one of the remaining terminals on the relay. Connect the other black wire from the GE Main Breaker to the terminal on the relay that is connected to the positive terminal of the 24VDC power supply.

Step 5: Connect Siemens Breaker Connect the white wire from the Siemens 50A 2-pole breaker to the remaining terminal on the relay.

Step 6: Install Diode Install a diode across the coil terminals of the relay, with the anode connected to the positive terminal of the 24VDC power supply.

Operation

When either Epo button is pressed, the relay will energize, opening the NC contacts and disconnecting power to the HVAC units. When the Epo button is released, the relay will de-energize, closing the NC contacts and restoring power to the HVAC units. The diode prevents voltage spikes from damaging the relay coil when the Epo button is released.

Note: Use wire of sufficient gauge to handle the load. Ensure all connections are secure and insulated to prevent short circuits. Test the system thoroughly to ensure proper operation. Flag for review