How Power Surges and Loose Electrical Connections Affect Fire Detectors

Linked smoke detectors function on the 120-volt AC electrical system that is hardwired into a building or residence. Most have backup batteries to power the smoke alarms in the event of a power outage. Hardwired smoke alarms are vulnerable to power surges, which may cause them to fail temporarily or even permanently.

As of 2002, code requires that all hardwired smoke detectors be on an arc fault circuit and come off a bedroom circuit, and that all smoke detectors be interconnected throughout the home. Only residential homes and apartments have battery backups in case of power failure. Commercial structures have a lock out on their breaker protection and this type of work needs a qualified NAPSAP certification. This is referred to as “Fire Alarms” that are addressable per device by story levels and rooms.

Furthermore, according to the newer electrical standards in the NFPA (National Fire Protection Association) – 72 edition, all dwellings must have a CO2 detector installed within 25 feet of each bedroom per each level of the home.

Loose Connections: Just as Damaging as A Surge

One cause of smoke detector failure may be a loose electrical connection. With most smoke alarms that function on AC or AC/DC power, a loose hot wire connection can intermittently disconnect power to the smoke alarm. The most common result of a loose connection is for the smoke alarm to “go off,” making a beeping or chirping noise. Unfortunately, the effect of a loose electrical connection is the same as a power failure. The units may alarm briefly when power is restored. A loose or disconnected neutral wire may cause the alarm to malfunction. Making sure the wire is making a reliable connection is important to improving the life and functionality of your smoke detector.

Of course, a loose connection will also drain a smoke detector’s battery. Typically, batteries only need to be changed two to three times during the life of a hardwired smoke detector, but this increases if the battery is being drained due to a loose connection.

When smoke detectors are changed out, typically the harnesses also need to be upgraded. It’s at this point, you might want to also check the smoke detector connections. While it’s certainly possible to complete this task as a DIY homeowner, it’s not recommended. Save yourself time and frustration by having your smoke detector connections repaired or replaced by a licensed professional.

What Are Power Surges?

A power surge occurs when there is a sudden, significant increase in the voltage of electricity flowing through your circuits. In the United States, most appliances and electronics work on 120 volts. During a surge, there’s a dramatic but brief boost in that voltage rate, which brings too much electricity running through your wires. Surges happen for a variety of reasons including severe weather conditions, electrical transformer problems, or the sudden return of power after an outage. The most common source of power surges is lightning, so be especially aware that the likelihood of a power surge increases during a thunderstorm.

Surges can be unpredictable– you never know when an unexpected disruption may affect the power grid. One sign of a power surge are lights flickering on and off. Additionally, you may also notice signs of a power surge if you come home to find your appliances, such as your oven or microwave clock has been reset. Hardwired smoke or CO2 detectors may be beeping as well. Also, the garage door opener may be fried, and 110 volt surge protectors in your wall sockets may be tripped. In some cases, hardwired items and plug-in appliances, like furnaces and refrigerators, become damaged.

Another cause of power surges is running too many devices at the same time on the same circuit. When high-powered electrical devices, such as air conditioning units or refrigerators, are working at peak capacity it takes a lot of energy to keep their motors and compressors going. This high demand can upset the steady voltage flow through your electrical system.

4 Major Causes of Power Surges

INTERNAL SURGES – These types of power surges are typically caused by equipment operation, such as motors turning on/off. Most large household appliances draw a significant amount of electricity when they are turned on, causing a brief drop in current for neighbors. When the appliance shuts off, it again causes the current to surge. While this seldom poses enough of a problem to damage most appliances alone, over time it can cause problems with sensitive electronics such as smoke detectors.

LIGHTNING – A lightning strike delivers very large voltage, rather than current, and is arguably the biggest culprit for a massive power surge. Equipment in the electrical grid has some protection from lightning strikes, but can still be susceptible to surging. Lightning can also produce surges from secondary effects such as by hitting a transformer which then fails. While you wouldn’t want to turn off your smoke detectors for every storm, lightning strikes are something to consider if your smoke detectors are not functioning properly shortly after a storm.

POWER GRID INFRASTRUCTURE — Damaged utility lines or utility grid transfers can be another reason you might experience power surges. The modern electrical grid is a complex network of equipment and power plants. Utility companies may decide to bring in power from additional power plants if a community experiences high electricity demand. The action of “switching” can make the line voltage surge, causing problems for sensitive electronics. Problems with electrical distribution equipment, such as overheated transformers and broken power lines, can also cause surges. Fortunately, damage from these kinds of surges can be mitigated by using a surge protector.

BLACKOUTS – This type of surge is both manageable and typically predictable. Blackouts, or internal power outages, happen when a large area loses electricity or the current in the power lines go to zero. Blackouts are the result of power lines that experience a large spike of current when the power comes back on. A blackout power surge can damage electronic and electrical equipment. As with electrical storms, you can prevent damage to many sensitive electronics by switching lights, appliances, and computers off during a blackout. Again, it’s not practical to disable your fire alarms, so they may become damaged in the event of a blackout.

Brownouts are power losses that can vary in scope. They can occur on a large city scale due to a substation issue, but can also be on a smaller scale that affects your neighborhood or just your individual house. This can be due to an aged transformer, a loose connection on some bug splices on an overhead pole, or a loose bug connection in an underground junction box.

A loose connection causes the voltage to drop on one leg and the current to rise. In the event of losing a neutral, this can create a high spike on one leg and a major drop on the second, which can result in a fire.

POWER GRID INFRASTRUCTURE — Another common cause of power surges are downed or damaged utility lines. When a power surge trips the circuit breaker controlling interconnected smoke alarms fitted with a battery backup, the smoke alarms should switch to battery power and function as normal. However, it’s recommended your smoke detector system be tested after any power surge or electrical storm that results in a power outage or tripped circuit breakers. Before running to the breaker box, make sure your batteries are functioning properly. If the beeping

continues, check the breaker box. Reset the circuit breaker as necessary, which should reset the error codes causing the beeping in a properly functioning interconnected smoke alarm system. Of course, this doesn’t always resolve the issue and you may need to contact an electrician.

Signs of Smoke Alarm Failure

After a power surge, hardwired, interconnected smoke alarms may behave erratically. Many people experience a beeping every few minutes or, in some cases, the alarm goes off at random times. More insidiously, a smoke alarm may fail silently if a large power surge damages the wiring in such a way as to prevent the warning beeps. In such a case, most homeowners may be unaware that the house is unprotected until the next time a test is conducted on the smoke detector(s), or until there is a fire.

It’s advised that you test smoke alarms monthly to ensure proper functioning during an emergency. In addition, test the system after any power surge or electrical storm that results in a power outage or tripped circuit breakers. Keep hardwired smoke alarms clean by vacuuming the exterior vents with the soft brush attachment of a vacuum cleaner. Unlike battery-operated units, you should not open the casing of a hardwired smoke alarm to clean the interior. Even with cleaning, by manufacturer’s specifications smoke alarms are only good for a maximum of 10 years.

Going Beyond DIY

Power surges can be particularly damaging to smoke detectors and there might be a more serious, underlying problem if outages seem to be a recurring event. Surges that continually trip the circuit breaker damage your smoke detector slowly. This often goes beyond the scope of a DIY project. Whole house surge protectors can be professionally installed at the main electrical panel that will help buffer surges, assuming there is enough room at the bus bar in the load center. These whole house protectors need a high joule rating, and it is best if they have two green indicator lights that show green for go and red for dead. This device should match the panel’s name as well as the breakers that feed the surge protector. The advantage to having a whole house 240 volt protector is that it complements the typically 110 volt plug-in devices, but also protects the smoke detectors that are hardwired in the walls and ceilings, as well as helping to protect your expensive 240 volt appliances. Of course, whole house protectors should be installed by a professional.

If you experience routine power failures, it will need to be checked by a professional electrician. A professional electrical contractor would be able to assess root causes, and provide suggestions on how to best resolve your specific needs.