First Alert 10-Year Battery Hardwired Smoke Detector with Battery Backup Ionization Interconnected – Model 1046848

The First Alert hardwired smoke detector (Model 1046848) is the residential fire safety standard for new construction and major remodels where building code requires hardwired interconnected smoke alarms. As a hardwired ionization smoke detector, the First Alert hardwired smoke detector connects directly to the home’s 120V electrical system through a dedicated 15-amp branch circuit and uses ionization sensing technology to detect fast-flaming fires from paper, grease, and similar materials. As the First Alert 1046848 model, this specific SKU has become a default specification for residential builders and electrical contractors who need a reliable code-compliant hardwired alarm at a predictable price. As an interconnected smoke alarm, this unit links with other compatible hardwired First Alert alarms throughout the home so when any single alarm detects smoke, every alarm in the interconnected system sounds simultaneously, providing whole-home alert that meaningfully improves the chance occupants will hear the warning regardless of which room or floor they are on. As a smoke detector with battery backup, the First Alert hardwired smoke detector includes a sealed 10-year lithium battery that takes over instantly if utility power fails, ensuring continuous protection during the exact outage events when fires are statistically more likely to occur from candles, generators, and improvised heating. Every First Alert hardwired smoke detector ships nationwide from IB Lighting with free shipping. Manufacturer specifications are available at the official First Alert website.

First Alert Hardwired Smoke Detector Key Highlights

Hardwired Installation: Why Hardwired Beats Battery-Only for New Construction

The defining feature of the First Alert hardwired smoke detector is the direct connection to your home’s 120V electrical system, which provides continuous power to the alarm without battery dependency under normal operation. This is the type of smoke alarm building code requires in new construction throughout most of the United States, and it is the type fire safety professionals recommend whenever electrical wiring is being run anyway (during construction, major renovations, or basement finishing projects).

The hardwired connection eliminates the most common smoke alarm failure mode that affects battery-only alarms: dead batteries. Under normal grid-powered operation, the First Alert hardwired smoke detector draws power continuously from the household electrical circuit, which means the alarm cannot be silenced by removing or failing to replace a battery. The 10-year sealed battery backup takes over only during power outages, and because it is rarely needed (most US homes experience only a few hours of outage per year on average), the sealed battery delivers its full 10-year service life with capacity to spare.

The hardwired installation does require a dedicated 15-amp branch circuit running from the home’s electrical panel to each alarm location, with the interconnect signal wire connecting between alarms. This is typically run during framing rough-in using 14/3 NM-B Romex (one black hot, one red interconnect signal, one white neutral, plus the bare ground), which is exactly what the Southwire 14/3 NM-B 250 ft Romex SIMpull handles. For new construction or major remodels, the hardwired alarm system is rolled into the overall electrical scope without major additional cost.

Interconnect Functionality: Why Whole-Home Alarm Coordination Matters

The interconnect capability of the First Alert hardwired smoke detector is genuinely meaningful for fire safety, not just a feature checkbox. When alarms are interconnected, smoke detection at any single alarm location triggers every alarm in the system to sound simultaneously. This means a fire starting in the basement triggers the alarm in the master bedroom on the second floor, giving occupants the maximum possible warning time regardless of which room or floor the fire originated in.

For comparison, standalone alarms (whether battery or hardwired without interconnect) only sound at the location where smoke is detected. A basement fire might trigger only the basement alarm, which may not be audible to occupants sleeping on the second floor. By the time the smoke spreads upward enough to trigger the bedroom alarm, the fire has been developing for many additional minutes, reducing escape time meaningfully.

Code requirements in most jurisdictions reflect this safety benefit. The International Residential Code (IRC) requires interconnected smoke alarms in all new construction and most major remodels. The interconnect signal travels on a third conductor in the wiring between alarms (the “red” wire in 14/3 NM-B installations), with each alarm capable of triggering the signal when it detects smoke and capable of sounding its own alarm when it receives the signal from any other alarm in the system.

The First Alert hardwired smoke detector interconnects with other compatible First Alert hardwired alarms. For mixed-installation scenarios where some rooms need ionization detection (this product) and others would benefit from photoelectric detection, First Alert offers compatible photoelectric hardwired alarms that interconnect with this unit on the same circuit. This provides whole-home coverage with the right sensor type for each room location.

10-Year Sealed Battery Backup: Continuous Protection During Outages

The sealed 10-year lithium battery backup in the First Alert hardwired smoke detector solves the one weakness of pure hardwired smoke alarms: power outages. When utility power fails (storm-driven outages, downed power lines, planned utility maintenance, equipment failures), purely hardwired alarms without battery backup would lose function entirely. The 10-year sealed battery in this First Alert hardwired smoke detector takes over instantly when utility power is lost, providing continuous fire detection capability through the entire outage.

This matters more than it might seem because the period during power outages is statistically when residential fires are more likely to occur. Homeowners light candles for illumination, run portable generators improperly, plug in improvised heating sources, and engage in other workaround behaviors that elevate fire risk. The hardwired smoke detector with battery backup specifically protects against fires during the exact conditions when traditional hardwired-only alarms would fail.

The “sealed 10-year” specification means the battery cannot be removed or tampered with, and it does not need annual replacement like 9V battery alarms. Under normal grid-powered operation, the battery rarely discharges because the hardwired primary power handles all monitoring duty. The battery sits in reserve for the rare outage events when it is actually needed, which means the battery delivers its full 10-year service life with capacity to spare. At the end of the 10-year service life, the entire detector unit is replaced (not just the battery), refreshing the sensor and electronics at the same time.

Ionization Sensing Technology: What This Sensor Type Detects Best

The First Alert hardwired smoke detector uses ionization sensing technology, which is one of the two main residential smoke detector sensor types. Understanding what ionization detects best helps you make the right deployment choice for each room location in your home.

Ionization sensors detect smoke through a small radioactive source that ionizes the air inside the sensing chamber, creating an electrical current. When smoke particles enter the chamber, they disrupt this current and trigger the alarm. Ionization sensors are especially sensitive to the small smoke particles produced by fast-flaming fires: paper fires, grease fires on a stovetop, fast-spreading flame fronts in furniture or curtain materials. These fast-flaming fires develop very quickly once flames are visible, and ionization sensors provide rapid alarm response in these scenarios.

Photoelectric sensors (a different product type) are more sensitive to the larger smoke particles produced by slow smoldering fires. Both sensor types have legitimate use cases, and the National Fire Protection Association recommends both types in residential installations for complete coverage. The ideal residential setup uses photoelectric alarms in sleeping areas (where slow-smoldering mattress and electrical fires are the dominant risk) and ionization alarms in kitchen-adjacent areas and living spaces (where fast-flaming cooking and paper fires are more likely).

The First Alert hardwired smoke detector is the ionization version of First Alert’s hardwired interconnected lineup. For sleeping areas where photoelectric coverage is preferred, choose the photoelectric variant. For mixed installations using both sensor types, both products interconnect on the same wiring system and trigger each other when any alarm detects smoke. Compare with the standalone First Alert photoelectric smoke detector 2-pack for battery-only photoelectric coverage.

When Hardwired Smoke Alarms Are Code-Required

The First Alert hardwired smoke detector is specifically the right product for installations where building code requires hardwired interconnected smoke alarms. Understanding when these requirements apply helps you specify the correct product for your project.

New construction: The International Residential Code (IRC) requires hardwired interconnected smoke alarms with battery backup in all new single-family and two-family residential construction. This requirement is universal across nearly every US jurisdiction. Battery-only alarms are not acceptable for new construction.

Major remodels and additions: Most jurisdictions require existing battery-only alarms to be upgraded to hardwired interconnected alarms when major renovation work is performed, particularly any work that involves opening walls or running new electrical wiring. The trigger threshold varies by jurisdiction, but typically any major bedroom addition, kitchen remodel, or whole-house renovation will trigger the upgrade requirement.

Permitted electrical work: Some jurisdictions require smoke alarm system upgrades when other electrical permit work is performed in the home, even if the permitted work is unrelated to the smoke alarm system itself. Check with your local building department before pulling any electrical permit on an older home with battery-only alarms.

Multi-family residential: Apartments, condominiums, dormitories, and similar multi-unit residential construction nearly always require hardwired interconnected alarms in each unit, with additional requirements for common-area alarms and integration with building fire systems. The First Alert hardwired smoke detector is the right specification for these projects.

For replacement of existing hardwired alarms (rather than upgrade from battery-only), the First Alert hardwired smoke detector is the direct replacement. Existing 14/3 wiring from the original install can typically be reused if it is in good condition.

Wiring Requirements for the Hardwired Install

Installing the First Alert hardwired smoke detector requires a properly designed electrical circuit that meets NEC and IRC requirements. For new construction or major renovation, the wiring is run during framing rough-in. For retrofit installations, the wiring is run through finished walls and ceilings, which is meaningfully more complex.

The smoke alarm circuit consists of a dedicated 15-amp branch circuit from the panel, typically protected by an arc-fault circuit interrupter (AFCI) breaker as required by current NEC. The circuit feeds the first smoke alarm in the home, then continues to each additional alarm in series. The cable used is 14/3 NM-B Romex with ground: black for the hot, red for the interconnect signal, white for the neutral, and bare copper for the ground. Each alarm has a 3-wire pigtail that connects to the cable at each box location.

The 14/3 cable carries the interconnect signal between alarms on the red wire, which is how the whole-home alarm coordination works. When any alarm detects smoke, it triggers a signal on the red wire, and every other alarm on the same circuit receives that signal and sounds its own alarm. The Southwire 14/3 NM-B 250 ft Romex SIMpull is the standard cable specification for residential hardwired smoke alarm circuits.

For a typical residential install with 5 to 7 alarm locations, a single 250-foot spool of 14/3 NM-B handles the entire system. Browse the broader IB Lighting electrical wire collection for additional wire sizes and accessories needed to complete the hardwired alarm install.

Important: This Is a Smoke Detector, Not a CO Detector

The First Alert hardwired smoke detector is specifically a smoke alarm, not a carbon monoxide (CO) alarm. The ionization sensor detects smoke particles only. Carbon monoxide is an invisible, odorless gas produced by incomplete combustion (gas appliances, fireplaces, automobile exhaust, gas-powered generators) that has its own dangerous health effects entirely separate from fire smoke. CO detection requires a different sensor type and a separate alarm.

Every US home should have BOTH smoke detection and CO detection for complete safety. Hardwired smoke detectors like the First Alert hardwired smoke detector handle fire risk. Separate CO detectors handle carbon monoxide poisoning risk. Some combination units integrate both sensors into a single device, but they are functionally two separate alarms in one housing. The First Alert hardwired smoke detector is the smoke-only configuration, which is appropriate for homes that also have separate CO detection or for installations where smoke detection alone is the focus.

If your home uses any gas appliances (gas furnace, gas water heater, gas range, gas fireplace, gas dryer), uses a wood-burning fireplace or wood stove, has an attached garage, or operates a gas-powered standby generator like a Generac Guardian standby generator, you have CO risk and need dedicated CO detection in addition to the smoke detector. The combination of fire safety and CO safety is what completes a residential life-safety package.

First Alert Hardwired Smoke Detector Specifications

First Alert Hardwired Smoke Detector FAQs

Who the First Alert Hardwired Smoke Detector Is Built For

The First Alert hardwired smoke detector serves three clear buyer types. The first is residential builders and general contractors specifying smoke alarms for new construction projects. For these buyers, hardwired interconnected alarms are required by code, and the First Alert hardwired smoke detector is the standard specification that satisfies the IRC requirement at a predictable price point. A typical single-family home build needs 5 to 7 of these units plus the matching 14/3 NM-B Romex for the interconnect circuit, and our team supports builders ordering both products together for project pricing.

The second buyer is the electrical contractor doing major remodels and additions where smoke alarm upgrades are triggered by the scope of work. When a homeowner adds a bedroom, finishes a basement, or does a kitchen remodel that involves opening walls, the existing battery-only smoke alarm system typically must be upgraded to hardwired interconnected. The First Alert hardwired smoke detector is the right specification for these upgrade projects, with the matching 14/3 NM-B Romex available through the same supplier.

The third buyer is the homeowner replacing an aging existing hardwired smoke alarm system. Most homes built since the late 1990s have hardwired interconnected smoke alarms by code, and these alarms reach end-of-service-life at the 10-year mark. The First Alert hardwired smoke detector is a direct replacement for existing First Alert hardwired alarms, with the existing wiring reusable if it is in good condition. Browse the broader IB Lighting electrical wire and safety product collection for related products.

Ionization vs Photoelectric Smoke Detectors: Which Should You Buy?

The two main residential smoke detector sensor types serve different fire profiles, and the National Fire Protection Association recommends both types for complete coverage. The First Alert hardwired smoke detector uses ionization sensing, and understanding when ionization is the right choice helps you specify the correct alarm type for each room.

Choose ionization like the First Alert hardwired smoke detector if you want fast detection of flame-front fires (paper, grease on a stovetop, fast-spreading curtain or upholstery fires). Ionization alarms are typically deployed in living rooms, kitchens (with appropriate distance from cooking appliances to avoid nuisance alarms), dining rooms, and other living spaces where fast-flaming fires are the dominant risk pattern.

Choose photoelectric like the First Alert photoelectric smoke detector 2-pack if you want best detection of slow smoldering fires (mattresses, upholstered furniture, smoldering electrical wiring). Photoelectric alarms are most commonly deployed in bedrooms and sleeping areas where slow-smoldering fires are the dominant fire-death risk.

For most residential installations, the ideal setup combines both sensor types: ionization alarms in living spaces and photoelectric alarms in bedrooms, all on the same hardwired interconnect circuit so any alarm triggers all alarms. First Alert offers compatible hardwired photoelectric alarms that interconnect on the same wiring as the First Alert hardwired smoke detector, allowing mixed-sensor whole-home systems.

Hardwired vs Battery-Only Smoke Alarms: When Each Is the Right Choice

The First Alert hardwired smoke detector and the standalone First Alert photoelectric smoke detector 2-pack serve fundamentally different installation scenarios. The choice between hardwired and battery-only is determined by code requirements, installation scope, and the existing alarm system in the home.

Choose hardwired like the First Alert hardwired smoke detector if you are doing new construction (required by code), doing a major remodel that triggers code upgrade (typically required), replacing existing hardwired alarms (direct replacement), or building a complete whole-home interconnected system from scratch. Hardwired alarms provide superior protection because they cannot fail from dead batteries during normal operation, and the interconnect capability provides whole-home alarm coordination.

Choose battery-only like the First Alert photoelectric smoke detector 2-pack if you are replacing existing battery-only alarms in homes that pre-date hardwired requirements, adding alarm coverage to existing battery-only systems, or operating in jurisdictions where battery-only sealed 10-year alarms remain acceptable for replacement. Battery-only alarms require no electrician, no wiring, and no permits, which makes them ideal for replacement and add-on scenarios.

Installation Tips for the First Alert Hardwired Smoke Detector

Installing the First Alert hardwired smoke detector requires electrical work and typically a permit and licensed electrician. For new construction, the wiring is run during framing rough-in by the electrical contractor as part of the overall electrical scope. For retrofit installations, the work is meaningfully more complex because cables must be run through finished walls and ceilings.

For each alarm location, the standard installation involves mounting an electrical junction box to a ceiling joist (or wall stud) where the alarm will be installed, running 14/3 NM-B Romex from the panel to the first alarm box and from each alarm box to the next alarm in the interconnect chain, and protecting the entire smoke alarm circuit with an AFCI breaker at the panel. The first alarm in the chain connects to all four conductors (hot, neutral, ground, plus interconnect signal). Subsequent alarms connect to the same four conductors through pass-through wiring.

The alarm itself mounts to the junction box using the included bracket. The alarm has a 3-wire pigtail (black for hot, white for neutral, red for interconnect signal) that connects to the household wiring using wire nuts. The mounting bracket is twist-locked to the box first, then the alarm is twist-locked to the bracket. Once power is applied, the alarm performs an initial self-test (audible chirp confirming operation) and enters normal monitoring mode. Test each alarm by pressing the test button on the face of the unit; if interconnected correctly, every alarm in the system should sound simultaneously when any single test button is pressed.

Maintenance and Testing for the First Alert Hardwired Smoke Detector

The First Alert hardwired smoke detector requires minimal maintenance over its 10-year service life. Hardwired primary power eliminates the dead-battery failure mode, and the sealed lithium backup battery eliminates the annual battery replacement task. The remaining maintenance items are simple.

Monthly test: Press and hold the test button on any one alarm in the interconnected system until the alarm sounds. If interconnection is working correctly, every alarm in the system should sound simultaneously. This confirms both the individual alarm operation and the interconnect signal integrity. If only one alarm sounds during a test, the interconnect wiring needs troubleshooting.

Periodic cleaning: Vacuum the exterior of each alarm every 6 months to remove dust accumulation from the sensing chamber vents. Dust accumulation can degrade sensor sensitivity and trigger nuisance alarms.

Response to chirp signals: If an alarm produces an intermittent chirp, the cause depends on the duty cycle and pattern. A chirp during a power outage typically indicates the backup battery is engaged and functioning. A persistent chirp during normal operation typically indicates either an internal fault or the end-of-life signal. For the First Alert hardwired smoke detector with its sealed battery, a persistent chirp during normal grid-powered operation typically means end-of-life and the unit should be replaced.

10-year replacement: At the 10-year service life mark, replace the entire unit. The sealed battery and the ionization sensor both reach end-of-service-life at approximately the same time. When replacing one alarm in an interconnected system, consider replacing all alarms in the system at the same time so they age together and reach end-of-life together, simplifying future replacement scheduling.

Browse the complete IB Lighting electrical and safety product collection, compare with the First Alert photoelectric smoke detector 2-pack (battery-only alternative), pair with the Southwire 14/3 NM-B 250 ft Romex SIMpull needed for hardwired interconnect wiring, consider pairing with a Generac standby generator for outage protection, or visit our customer FAQ hub. Manufacturer technical sheets are available at the official First Alert website.