Okay, this is a tricky situation and requires careful consideration for both safety and code compliance. It is absolutely crucial that you understand and adhere to all applicable electrical codes and regulations in your area. If you are not a qualified electrician, you should consult with one. Incorrect wiring can create dangerous conditions, including electrical shock and fire hazards, and could jeopardize the functionality of safety systems.Let's break down the situation and how to approach it

Understanding the Problem
Shunt Trip Function

The shunt trip breaker is designed to remotely open the elevator's main breaker. It accomplishes this by receiving a signal (typically a voltage) that activates a solenoid within the breaker, causing it to trip.

Remote Location

The physical separation of the shunt trip breaker from the main elevator breaker is the core challenge.

Wiring Requirements

You have the hot (typically black or red) and neutral (typically white) from the shunt trip breaker, and you need to interface this with the fire alarm relay. You

do not have direct access to the main elevator breaker for direct wiring. Fire Alarm Relay

The fire alarm relay provides a contact closure (or opening) upon alarm, which you will use to trigger the shunt trip.

Possible Solutions and ConsiderationsImportant Note

The following solutions assume that you are using the fire alarm relay to energize the shunt trip coil. Some fire alarm systems use a normally closed contact that opens upon alarm to de-energize a circuit. In this case the below solutions would have to be modified.1.

Dedicated Power Supply for Shunt Trip Coil (The Preferred Method) Concept

The safest and most reliable method is to use a separate, dedicated, listed power supply for the shunt trip coil. This power supply is independent of the elevator's main power. You wire this power supply to the shunt trip breaker's coil terminals.

Wiring


Power Supply

Install a listed power supply (120VAC or 24VDC, depending on the shunt trip coil voltage) near the shunt trip breaker. Wire the power supply to a separate general-purpose circuit.

DO NOT connect the power supply to the elevator's main power circuit.2. Fire Alarm Relay

Connect the fire alarm relay contacts in series with the power supply output to the shunt trip coil. The typical wiring would be: power supply positive (+) -> fire alarm relay normally open contact -> shunt trip coil positive (+). The power supply negative (-) connects directly to the shunt trip coil negative (-). When the fire alarm relay closes (upon alarm), it completes the circuit, energizing the shunt trip coil and tripping the breaker.

Advantages



Isolation

Completely isolates the shunt trip circuit from the elevator's main power.

Reliability

Ensures the shunt trip can function even if there are problems with the elevator's main power.

Safety

Simplifies troubleshooting and reduces the risk of accidental energization.

Important Considerations



Power Supply Listing

Ensure the power supply is listed for fire alarm applications or a similar purpose.

Voltage Matching

Absolutely critical that the power supply voltage matches the voltage required by the shunt trip coil. Using the wrong voltage will damage the shunt trip.

Supervision

Consider using a power supply that includes supervision, meaning that it can report a fault condition (e.g., power failure) back to the fire alarm panel. This ensures the shunt trip is always ready to operate.2.

Using a Separate General Purpose Branch Circuit (Potentially Problematic) Concept

Use a general-purpose branch circuit to power the shunt trip coil. This is similar to the dedicated power supply, but instead of a dedicated power supply, you are tapping into an existing 120V outlet or lighting circuit (that is NOT the elevator power.)

Wiring

1. Find a nearby 120VAC general-purpose branch circuit. Confirm that it is on a different circuit breaker than the elevator's main power.
2. Wire the hot and neutral from this branch circuit to a junction box near the shunt trip breaker.3. Connect the fire alarm relay contacts in series with the hot wire to the shunt trip coil, as described in the dedicated power supply method.

Advantages

Potentially simpler than installing a new power supply if a suitable circuit is readily available.

Disadvantages and Concerns



Code Compliance

Potentially problematic under electrical codes. Fire alarm circuits are typically required to be on dedicated circuits to maintain reliability. Tapping into a general-purpose circuit can violate this requirement.

Load Impact

Adding the shunt trip coil to an existing circuit could overload the circuit, causing nuisance tripping.

Reliability

The shunt trip is dependent on the reliability of the general-purpose circuit. A failure on that circuit would disable the shunt trip.

Voltage Matching

Absolutely critical that the branch circuit voltage matches the voltage required by the shunt trip coil.

Important Considerations



Consult with an electrician

Essential to ensure that this approach complies with all applicable codes and regulations.

Load Calculation

Perform a load calculation to ensure that the circuit can handle the additional load of the shunt trip coil.

Circuit Identification

Clearly label the circuit breaker that feeds the shunt trip circuit to prevent accidental disconnection.3.

Considerations (Applicable to both methods) Supervision

It is highly recommended that the wiring between the fire alarm relay and the shunt trip device be supervised. This is to ensure that if any wiring faults occur (such as a cut or shorted wire) the fire alarm panel can annunciate the trouble.

Wire Sizing

Use appropriate wire size for the shunt trip coil current.*

Conduit

Protect all wiring in conduit.

Why Direct Wiring to the Main Elevator Breaker is Typically Required

Direct wiring to the main elevator breaker is often the ideal solution because it ensures that the shunt trip is directly related to the elevator's power source. This can simplify troubleshooting and improve reliability. However, when physical separation makes this impractical, the alternative methods described above can be considered.

Crucial Steps


Consult with a Qualified Electrician

This is non-negotiable. Explain the situation, show them the equipment, and have them design and install the wiring in accordance with all applicable codes.2.

Consult with Fire Alarm System Vendor

Discuss your plans with the fire alarm system vendor to ensure compatibility and proper integration.3.

Inspect and Test

After installation, thoroughly inspect the wiring and test the shunt trip functionality to ensure it operates correctly. Document the testing.4.

Labeling

Clearly label all wiring and components to indicate their purpose.

In summary, avoid wiring the shunt trip directly to a general-purpose outlet or lighting circuit unless you have the explicit approval of a qualified electrician and the local authority having jurisdiction (AHJ). The safest and most reliable solution is to use a dedicated, supervised power supply. Flag for review