Proper elevator shunt trip wiring involves more than simply connecting a fire alarm relay to a shunt-trip breaker. The fire alarm designer must identify the emergency control interface device (ECID), determine which control pathway requires supervision, verify the electrical characteristics of the controlled circuit, and select an interface device suitable for the application.
This guide focuses specifically on the fire alarm interface and supervision side of elevator shunt-trip wiring, including ECID placement, addressable modules, interface relays and control-circuit supervision.
If you are looking for the complete elevator shutdown sequence instead, including the heat detector, fire alarm relay, shunt-trip disconnect, sprinkler relationship and elevator power removal, see our Elevator Shunt Trip Wiring Diagram & Power Shutdown Guide.
Elevator Shunt Trip Wiring Diagram
The diagram above illustrates two concepts for interfacing a fire alarm system with elevator shunt-trip equipment.
The important concept is not the specific NOTIFIER part number. It is understanding where the emergency control interface occurs and how the fire alarm control pathway is supervised.
What Is an ECID?
ECID stands for Emergency Control Interface Device.
In practical fire alarm design, the ECID is the interface through which the fire alarm system performs the required emergency control function.
For an elevator power-shutdown application, the ECID may be an addressable fire alarm interface located appropriately for the controlled equipment, or the design may use a supervised fire alarm control circuit operating another listed interface relay.
Which device serves as the actual interface depends on the system architecture.
This distinction matters because moving the interface farther away from the addressable fire alarm module can create an additional field-wiring pathway that must be considered in the supervision design.
The Basic ECID Concept
A useful way to visualize the arrangement is:
FACU → Supervised Fire Alarm Pathway → ECID → Controlled Emergency Function
For an addressable fire alarm system, the signaling line circuit itself is supervised by the fire alarm control unit.
However, simply having an addressable module somewhere in the system does not automatically mean every conductor beyond that module is supervised.
That is the key issue this article addresses.
Method 1: Addressable Relay at the Elevator Interface
One approach is to locate an addressable relay module at the point where the fire alarm system interfaces with the elevator power-shutdown control equipment.
The original example used a NOTIFIER FRM-1 addressable relay module.
The FRM-1 communicates with the compatible fire alarm control panel over the SLC and provides isolated Form-C relay contacts for controlling external equipment.
Conceptually:
FACU → Supervised SLC → Addressable Relay at Interface → Shunt-Trip Control Equipment
Locating the addressable interface at the controlled equipment can minimize the amount of unsupervised control wiring between the fire alarm interface and the equipment being controlled.
NOTIFIER FRM-1 Relay Module
The FRM-1 is an addressable relay module that allows a compatible NOTIFIER fire alarm control panel to operate dry relay contacts by command.
It provides two isolated Form-C contact sets that operate together.
This makes the FRM-1 useful for many fire alarm emergency-control interfaces where dry contacts are appropriate.
But there is an important limitation:
The FRM-1 is a relay module, not a universal power-control device.
The circuit being switched must remain within the manufacturer's listed contact ratings for the specific:
- Voltage
- Current
- AC or DC application
- Resistive or inductive load
- Coded or non-coded operation where applicable
Never choose an interface relay based solely on its largest advertised ampere rating.
Why Relay Contact Ratings Matter
Relay contacts are not rated identically for every electrical load.
A contact capable of switching one current at a low-voltage resistive load may have a significantly different rating when switching an inductive load or a different voltage.
Shunt-trip coils and other control equipment can present electrical characteristics that must be checked against the relay manufacturer's published ratings.
What If the Fire Alarm Relay Cannot Directly Control the Load?
If the fire alarm relay contacts are not suitable for the circuit being controlled, the design can use an appropriately rated listed interface relay.
The fire alarm system then controls the interface relay rather than attempting to switch the external control load directly.
Conceptually:
FACU → Supervised Control Module → Interface Relay → Shunt-Trip Control Equipment
This is where the supervision design becomes especially important.
Method 2: FCM-1 With an External Interface Relay
The second arrangement in the original diagram uses a NOTIFIER FCM-1 addressable control module to operate an external interface relay.
This is fundamentally different from using an FRM-1.
The FRM-1 provides addressable dry relay contacts.
The FCM-1 provides a supervised control output designed to monitor the wiring connected to its output circuit.
NOTIFIER documentation describes the FCM-1 as capable of supervising its output wiring and reporting conditions such as normal, open and short to the fire alarm control system.
That capability is why a supervised control-module arrangement can be useful when an external interface relay must be located away from the addressable module.
Why Use an External Interface Relay?
An external interface relay may be necessary when:
- The controlled voltage exceeds the appropriate rating of the fire alarm relay contacts
- The controlled current exceeds the appropriate contact rating
- The load characteristics are not suitable for the addressable relay
- The project design requires a different listed interface
- A supervised control circuit must extend from the fire alarm module to the final interface
The interface relay must itself be properly selected for the electrical characteristics of the controlled circuit.
The original diagram used a PR-1 style interface relay as an example. The exact relay used on a modern project should be selected from the approved equipment for that particular system rather than treating one legacy part number as universally required.
FRM-1 vs. FCM-1 for Elevator Shunt Trip
| Feature | FRM-1 | FCM-1 |
|---|---|---|
| Basic Device Type | Addressable relay module | Addressable control module |
| Typical Output | Dry Form-C relay contacts | Supervised control output |
| Output Wiring Supervision | Dry contacts do not inherently supervise the external controlled circuit | Designed to supervise connected control wiring when installed as specified |
| Useful Application | Local dry-contact interface where appropriate | Supervised pathway to an external interface/load where appropriate |
| Key Design Check | Contact voltage/current/load rating | Compatible external supply, supervised circuit and connected load |
Why Module Location Matters
One of the easiest mistakes to make with emergency-control wiring is to focus entirely on the fire alarm panel and ignore where the actual interface device is located.
Consider two arrangements:
Arrangement A:
FACU → SLC → Addressable Interface → Controlled Equipment
Arrangement B:
FACU → SLC → Addressable Module → Long Field Control Circuit → Interface Relay → Controlled Equipment
Arrangement B introduces another pathway between the addressable module and the final interface.
That pathway cannot simply be ignored because the module itself has an address.
If the design requires supervision of that control pathway, the module and circuit architecture must provide that supervision.
What Wiring Is Actually Supervised?
This is the question every technician should ask when looking at an elevator shunt-trip interface.
Do not stop at:
"The module is addressable, so it's supervised."
Instead ask:
- Is the SLC supervised?
- Where is the emergency-control interface located?
- Is there additional wiring between the addressable module and that interface?
- Is that additional wiring supervised where required?
- Is external control power monitored where required?
- Would an open conductor prevent the required emergency function without creating a trouble indication?
Those questions expose the difference between an addressable device and a completely supervised emergency-control interface.
Supervising Shunt-Trip Operating Power
The control pathway is only part of the design.
The shunt-trip mechanism also needs the electrical power necessary to perform its required function.
If that operating power disappears, the fire alarm control relay could function perfectly while the elevator power-shutdown mechanism fails to operate.
Where required by the applicable design and code, loss of power necessary for the emergency control function must therefore be monitored so the impairment does not remain hidden.
The exact method depends on the shunt-trip equipment, control-power source and approved fire alarm design.
Do Not Confuse Control Power With Elevator Motor Power
The fire alarm system normally interfaces with the control side of the elevator power-shutdown equipment.
It is not routing the elevator motor feeder through an ordinary addressable fire alarm module.
The fire alarm interface operates the approved shunt-trip or disconnecting mechanism, which then performs the required power-disconnection function.
This distinction is important both electrically and from an equipment-listing standpoint.
Normally Open or Normally Closed?
There is no responsible universal answer that says every elevator shunt-trip interface should simply use the normally open or normally closed contacts of a relay.
The correct contact arrangement depends on:
- The shunt-trip equipment
- The control voltage
- The approved sequence
- The supervision method
- The interface relay
- The required normal and activated states
- The equipment manufacturer's instructions
Follow the approved wiring diagram rather than selecting NO or NC based on habit.
Do Not Use the SLC as Proof That Everything Is Supervised
This deserves repeating because it is a common misunderstanding.
An addressable module being supervised on the SLC proves that the fire alarm control unit can communicate with that module.
It does not automatically prove that every conductor, relay coil, external power supply, or controlled circuit beyond the module is supervised.
Each part of the emergency-control interface must be evaluated according to what happens if that portion of the circuit opens, shorts, loses power or otherwise becomes impaired.
Common Elevator Shunt Trip Interface Mistakes
- Using a relay without checking its actual contact rating.
- Assuming an addressable relay supervises wiring connected to its dry contacts.
- Installing the addressable module far from the final interface without evaluating the intervening wiring.
- Confusing an FRM-1 relay module with an FCM-1 supervised control module.
- Failing to monitor power required to perform the shutdown function where required.
- Routing loads through fire alarm contacts that are not listed or rated for the application.
- Assuming NO or NC contacts are universally correct.
- Using legacy part numbers without checking current product documentation and compatibility.
- Testing only the fire alarm module rather than the complete emergency-control function.
Testing the Elevator Shunt Trip Interface
Testing should verify more than whether the addressable module changes state.
The complete test should be coordinated with the elevator contractor and other responsible parties and should verify the approved sequence from initiating condition through the final controlled function.
Depending on the installation, this can include:
- Correct fire alarm input
- Correct system programming
- Addressable module operation
- Supervision of the applicable control pathway
- External interface relay operation
- Availability and monitoring of required control power
- Operation of the approved elevator shutdown interface
- Correct trouble indication when a supervised pathway is intentionally opened during testing
- Proper restoration after the test
Frequently Asked Questions
What is an ECID in a fire alarm system?
ECID stands for Emergency Control Interface Device. It is the interface through which the fire alarm system performs an emergency control function such as an approved elevator power-shutdown operation.
Can an FRM-1 be used for elevator shunt trip?
An FRM-1 provides addressable dry relay contacts and may be suitable for an approved emergency-control interface when its application, contact ratings, location, supervision arrangement and equipment compatibility satisfy the project requirements. It should not be treated as a universal shunt-trip solution.
What is the difference between an FRM-1 and FCM-1?
The FRM-1 is primarily an addressable relay module providing Form-C dry contacts. The FCM-1 is an addressable control module capable of supervising its connected output wiring when installed in accordance with the manufacturer's instructions.
Does an addressable relay automatically supervise the shunt-trip circuit?
No. The fire alarm system supervises communication with the addressable module, but dry relay contacts do not automatically supervise all external wiring connected beyond those contacts.
Why would I use an FCM-1 with an interface relay?
A supervised control module can be useful where the fire alarm system must supervise the control wiring extending to an external interface relay. The external relay can then be selected for the electrical characteristics of the controlled circuit.
Can I use any 10-amp relay for elevator shunt trip?
No. Relay suitability depends on more than a single ampere rating. Verify voltage, AC or DC operation, load type, contact rating, listing, control characteristics and compatibility with the approved design.
Does the fire alarm relay carry elevator motor power?
Normally, no. The fire alarm system interfaces with the control circuitry for the approved elevator power-disconnection equipment. Elevator motor power is not normally routed through an ordinary addressable fire alarm relay.
Related Elevator Fire Alarm Guides
- Elevator Shunt Trip Wiring Diagram | Fire Alarm Power Shutdown
- Elevator Shunt Trip Requirements & Codes
- Elevator Recall and Shunt Trip Basics
- Heat Detectors and Elevator Pits
Final Thoughts
The most important concept in elevator shunt-trip interface wiring is understanding exactly where the emergency control interface occurs.
If an addressable relay is located at the final interface, the supervised SLC brings the fire alarm system directly to that point, but the dry contacts themselves do not automatically supervise the external circuit.
If an external interface relay must be located beyond the addressable device, a supervised control-module arrangement may be appropriate so the wiring to that interface can be monitored.
In either case, the designer must verify the relay ratings, control voltage, supervision requirements, equipment listings and approved elevator shutdown sequence.
Don't ask only, "Is the module supervised?" Ask, "Is the entire required control pathway supervised to the point where the emergency function is actually performed?"
