Is the Back-Fed 8-Volts Normal? -- What is really being done is that the 8-volt power source is forced to lock-step to 24 volts when there's an alarm. The fire alarm panel and the air handler may work together for now, but in the future, if there's any....
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How Can I Find a NAC Trouble? -- NAC2 is the alarm part. It's a Notification Appliance Circuit, or output circuit, that carries power to the horns and strobes in then building. It is a pair of wires attached to the NAC2 screw terminals on the panel, and has horns and-or strobes connected. It also has an End of Line Resistor...
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How can I Detect a Ground Fault? -- Using the voltmeter to get two separate battery voltage readings is a better way of detecting a ground fault. The first reading is to measure the voltage on the battery between the plus battery contact and ground. The second reading is to measure the voltage on the battery between the minus battery contact and ground...
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Why do Some of the Horns and Strobes Fail? -- If the employees used their voltmeters to determine the voltage polarity on the wiring, and put the wire measured positive on the plus terminal, the horn or strobe won't work. On a Notification Appliance Circuit (NAC), the voltage on the wires change polarity, depending on whether the control panel is sounding the alarm, or just...
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How do You Test a Battery? -- You can watch the battery voltage go up, or go down, depending on whether the battery is being charged or being used. Usually, the finding out of the current from a battery isn't needed for Planned Preventative Maintenance -PPM-. Remember, the amount of current coming out of the battery is the same current that the panel uses. However, when....
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How can I Test the Fire Alarm's Bell circuit? -- The panel is always checking the continuity of the wires in the bell circuit. To sound the alarm for everyone, in case of fire or other danger, the panel is making sure all the horns, strobes, or bells remain connected...
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Can I Add Just Four More Horn/Strobes? -- The AHJ may require official Voltage Loss Calculations on the whole circuit, including the old horns, strobes, and with the added wiring included in the circuit. If the current in the added horns and strobes, and the voltage loss in the added wiring fails...
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Can We use PVC Conduit Above a Suspended Ceiling? -- Is the suspended ceiling being used for returning the room air to the air handler? If so, the entire space above the suspended ceiling would be considered to be a -Return Air Plenum-. No wiring, or anything else for that matter, can...
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How do We Make the Conventional Sounder Bases Work? -- Normal Turn On - This would be the building's fire alarm sounding a general alarm throughout the building. When the power supplied by the NAC is sending forward voltage - the blocking diode inside the horn allows current to pass through the fire horn, sounding the alarm. When the general alarm is not sounding, the voltage is...
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Can Water Cause False Fire Alarms? -- Because of the water, you can't count on the device to show what is happening. Water on a duct detector should send data on the SLC saying -This is device number 027 and I'm in trouble-, but because of the water messing up the electronics in the duct detector, it sends -This is device number 135 and I'm in alarm-. The 135 is a false address...
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What does High Resistance in Loop Mean? -- Resistance, in any circuit, is not alone. Both voltage and current are interrelated with resistance, so if resistance is changed, either the voltage changes, or the current changes, or both the voltage and the current change. Because the panel...
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How do I Disconnect a Horn/Strobe to Redo the Paneling? -- When you disconnect the horn/strobe, some of the other horn/strobes are also disconnected. The trouble light showing up on the panel, showing you that you have disconnected part of the system, isn't a problem; the trouble light showing up on the panel, showing you that you have disconnected part of the system, is a feature. It is reminding you that you've disconnected something...
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How do I Troubleshoot the NAC Circuit? -- The panel, when supervising, isn't really checking to see that the horns and strobes work. The panel, when supervising, is checking to make sure all the horns and strobes are connected. It checks to make sure they're connected by running a small current, backwards, through all the wires...
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How are Real-World NAC Voltage Loss Calculations Performed? -- On the actual printed circuit boards, very few fire alarm control panels have as many programmable relays as are needed. For this reason, addressable control panels are required, and the relays are addressable control relays that are attached to the Signaling Line Circuit -SLC-. This is the same SLC that has the smoke detectors and heat detectors...
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How are Real-World NAC Voltage Loss Calculations Performed? -- In the real world, installers don't measure the length of the installed wire to make sure it will match the engineered plans. Sometimes the wire has to take longer routes than the installation plans, and any additions made after the original installation are usually not shown on the ...
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Why am I Seeing a Bell Open Circuit? -- The fire alarm system is useless if the detection devices or the warning devices aren't connected to the control panel through the wiring. The control panel checks to make sure the devices are connected by running a small electrical current through all of the wires. In essence, the panel is...
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How do I Troubleshoot this Turned-Off Fire Alarm System? -- Start by pretending that the system is a brand-new system. Remove all the devices, including smoke detectors, pull stations, horns, strobes, etc. Also, disconnect the input and output loops from the panel. At this point, you can concentrate on the wires, and not have any interference from any devices or the panel...
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Is There a Code that Forbids the use of Tie-Wraps? -- Proper using of tie-wraps in a fire alarm system isn't instinctive. To properly use tie-wraps in a fire alarm installation, the installer has to be very experienced, have the proper training, or both. It is really not very intuitive to use the tie-wraps correctly, and use them according to their listing...
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What does Dirty Power Mean? -- Originally, when nothing is connected to a generator, the voltage output of an AC generator will look like a clean sinewave. Any added signal to the AC sinewave makes the AC voltage dirty...
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How do You Use a Low Voltage Insulation Tester? -- A ground fault detector is an ohmmeter. The only difference is the extra 36 volts of battery voltage, and a resistor, added in series to one of the test leads. To build a ground fault detector for use on fire alarm systems, use the instructions...
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How do I Disconnect a Horn/Strobe to Redo the Paneling? -- When you disconnect the horn/strobe, some of the other horn/strobes are also disconnected. The trouble light showing up on the panel, showing you that you have disconnected part of the system, isn't a problem; the trouble light showing up on the panel, showing you that you have disconnected part of the system, is a feature. It is reminding you that you've disconnected something...
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Can You Use Four Conductor Cables for Sounder Bases? -- The SLC, because of capacitive lag, works better with smaller diameter wires; the power wires for Low Frequency Sounder Bases works better with larger with larger diameter wires. You are better off using two 2-conductor cables than trying to use one 4-conductor cable...
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How do I Find this Intermittent NAC Short? -- The panel is showing short, but the panel isn't very good at troubleshooting. It calls almost any AC or DC wire-to-wire leakage a short. It may even see a soft ground fault as a wire-to-wire short. Instead of reacting the word -short- on the panel, use your test instruments instead...
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Is it Mandatory to Report a Ground Fault? -- A single ground fault in a fire alarm system usually doesn't affect the fire alarm system - the fire alarm system will usually still detect fires and warn people of fires. But then again, that's only a single ground fault, or the -First Ground Fault-...
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Is that Stray AC Voltage on the Fire Alarm System Wiring OK? -- Any wire is a transmitting antenna, and any wire is a receiving antenna. If an AC signal is carried by a wire, that wire will produce a magnetic field, and the AC will vary the strength of the field. All other wires will receive this varying magnetic field, and generate a signal from the varying magnetic field. The strength of the AC signal depends on how well the wires are coupled together...
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Is that Stray AC Voltage on the Fire Alarm System Wiring OK? -- Any wire is a transmitting antenna, and any wire is a receiving antenna. If an AC signal is carried by a wire, that wire will produce a magnetic field, and the AC will vary the strength of the field. All other wires will receive this varying magnetic field, and generate a signal from the varying magnetic field. The strength of the AC signal depends on how well the wires are coupled together...
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Will a Reverse-Wired Device Stop Other Devices? -- All manufacturers have designed their building-wide fire alarm systems to be wired a specific way. The manufacturers show how to wire the devices in the installation sheets that come in the boxes included with the devices...
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Finding a Non-Linear Ground Fault -- Doubling the voltage across water from 4 volts to 8 volts will often increase the current by 10 to 20 times. Doubling the voltage on a working 25-volt surge suppressor from 15 volts to 30 volts will increase the current by at least 50 times. When the voltage doubles across the knee on either water or a surge suppressor, the current increases many times what the voltage has increased. That is a non-linear relationship...
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Why is Our Signaling Line Circuit Shorting-Out? -- For your purposes, consider the panel's Addressable Signaling Line Circuit, or SLC output, to be a power supply output. The panel's SLC output is what provides the power for all of the addressed portions of the SLC's detectors and modules...
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Why is the Pull Station Not Resetting? -- When the reset button on the is pressed on the fire alarm panel, a reset signal is sent to the electronics inside the panel, and also to all the devices in the building. The panel, though, will not reset until it has received a message from all of the devices saying, in essence, -I'm Normal, Not in Alarm-. The panel has to know that all the devices in the building are back to normal. The pull station did not tell the panel it was reset, so the panel stayed in alarm...
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Why Does the Alarm Keep Sounding? -- It could be that the fire alarm communicator is having problems that prevent it from calling the fire monitoring company if there's a fire. Every 24 hours, it checks to make sure the whole communication system is working. If it can't send out alarms, it will turn on its local sounder to get your attention...
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Can Water Cause a Ground Fault? -- Water conducts electricity. Water, though, is not like a copper conductor, which conducts electricity at very low resistance, no matter what voltage is applied. Water conducts very poorly at less than, say, 5 volts, but conducts a lot better at higher voltages of, say, more than 9 volts. If the voltage is even higher, say 13 volts, water conducts even better...
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Does Crosstalk from Strobe Circuits Affect Speakers? -- Crosstalk between wires is usually caused by transformer action. Transformer action is one wire has varying electrical current, which causes a varying magnetic field, and other wire generating current because of the varying magnetic field. This kind of cross-talk occurs very often, but usually is not a problem...
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How do I Find this Hard-to-Find Ground Fault? -- When eliminating the impossible, start with the easy stuff. Make sure the problem isn't something easy to find. Start with the batteries. Making sure the batteries aren't leaking some current to ground is really easy...
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How Do I Test Beam Detectors? -- A beam detector goes into alarm when a room is just starting to fill up with smoke. In the early stages of a fire, the smoke only blocks the light beam a little bit - it allows most of the light to pass to the reflector and back. Once the light beam is totally blocked by the smoke, a fire has gotten out of control. On the other hand, false alarms are not appreciated by anyone. A janitor...
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What is a Ground Fault? -- With the exception of the ground fault circuitry inside the fire alarm control panel (FACP) itself, the wiring for fire alarm systems has...
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How do I Connect 24 Volt Horns and Strobes to a 12 Volt Panel? -- I have a Silent Knight 5104b panel with a few IDC's and about 8 Strobe Horn combos. Problem is the FACP is 12 Volt DC and the Horn/Strobes are 24 Volt DC. Without swapping out all the Strobes with 12 volt strobes and have to get a lift or swapping out the 5104b with a panel that is 24 VDC, Can I connect a 24 Volt Power Booster to the 5104b and ...
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Why Can't I Reset the Panel After Disconnecting the SLC? -- I disconnected the SLC (Signalling Line Circuit) from the Loop Controller Module on the fire alarm panel. I tried to reset the fire alarm system, but it wouldn't reset. What does that mean? Is there a short on the loop? The loop is disconnected, is there a problem with the Loop Controller Module?...
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How do You Use the Switches for Addressing? -- The DIP (Dual In-line Package) Switches are a little simpler than the thumbwheels (and therefore more cumbersome). A switch has 2 positions (0 through 1) rather than 10 positions (0 through 9) or 16 positions (0 through F). They work in Binary; either they are off or they are on. Two-positions means Binary, and Binary is the type of signal sent over the two wires of the Signaling Line Circuit (SLC)...
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How Can I Tell if the Batteries are Bad? -- When I first checked the batteries they read 12.65 Volts and 22 Amp Hours. I checked the batteries with a battery tester, not a multi-meter. After the low amp hour reading, it was recommended they replace the batteries due to low amp-hours. According to NAPA 72...
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Can a Strobe be Connected to a Horn Circuit? -- As the building is currently wired, does the system use separate horn and strobe circuits? If the answer is yes, then out of common practice, all strobes go on the strobe circuit and all horns go on the horn circuit. No strobes should ever go on the horn-only circuit because the system was designed to have separate circuits...
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Which Proposal - Module in Stairwell or in Panel? -- Question: We're planning to have addressable panels installed and we've seen two approaches proposed by vendors for connecting the switches. One proposal uses addressable input modules at each switch, while another uses addressable zone modules in the panels. Is one method better than the other? Since the switches are already in zones by floor per building, they can be pinpointed already...
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How do You Find a Ground Fault? -- When there's a ground fault, the fault is an electrical leakage. It could be a hard ground fault, like a copper wire in the fire alarm system contacting ground. It could be a soft ground fault leaking electrical current through worn or pinched insulation, or even a soft ground fault caused by water on the wiring or devices. It could be an induced ground fault like the magnetic coupling of power inside of conduits. An ohmmeter can easily detect a hard ground fault. It's not so good with...
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Is it allowed by code and the AHJ (Authority Having Jurisdiction) to use wire nuts? -- The AHJ is the government's representative - the fire marshal or fire inspector, the insurance company's representative - the insurance inspector, the building owner - the architect and engineers with the overall design of the fire alarm system, and so on. I'm paraphrasing, but in essence, the NFPA Code, in their definitions, defines the Authority Having Jurisdiction as each of these...
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How does Capacitance and Shielding Affect Wiring? -- Especially with shielded wire, could you explain the role capacitance plays in fire alarm circuits? I have a very basic understanding of how a capacitor works -a storing of voltage- but I've heard stories of capacitance causing issues on SLC circuits. Could you elaborate on that? ...
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Should We use Canned Air with Smoke Detectors? -- I have called the fire alarm manufacturer and their response was - Warranty void if you blow canned air into the smoke detectors. Yes.. it's what we have been taught to do. But if the manufacturer won't back this practice, why are we doing it? It's a concern. I am field guy. If the device can't take a bit of a beating then it needs to be replaced. If I am to train my team in general practice, then I have to be sure. To blow canned air, or not. That is our question...
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Can a Vacuum Cleaner Really Clean a Smoke Detector? -- Many manufacturers will void their warranty if canned air used to clean a smoke detector. Once a smoke detector has compressed air blown into it, they won't stand behind their product because of potential damage caused by the high velocity air...
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What Does DC TOO LOW 2 Mean? -- That's a question that is better asked of the technical support people at GENT. They can help you with all the messages on the screen, and with many other troubles with that exact panel. Before talking to them, though, make sure you have...
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Are Dead Fire Alarm Batteries Dangerous? -- The batteries are needed in case there is a power blackout. As long as there is no blackout, the batteries aren't needed. But then, blackouts are difficult to predict, so batteries are needed, just in case. The Amp Hour rating printed on the side of the battery is the size of the container. The 7 Amp Hour batteries, when they are fully charged, are capable of providing 1 amp of electrical current for 7 hours. If your fire alarm system is...
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Should I Replace the Smoke Detector if it is 80% Dirty? -- Inside the detector is a computer that senses how much light is reflected over a 24 hour period, and averages that amount. It then adjusts the smoke detector to be less sensitive, so only dangerous smoke suddenly entering the chamber will be considered dangerous smoke...
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Can I Make an Earth Fault Disappear? -- If dip switch is disabled in the fire alarm control panel, can it make a fault disappear, such as an earth fault? - - An Earth Fault or Ground Fault light is a warning light on the fire alarm system saying -Somewhere in the building, electricity is leaking to the earth or ground-. The Earth Fault usually isn't in the box-on-the-wall called the fire alarm panel - the Earth Fault is usually...
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How Can I Feel More Secure when Working on Fire Alarms? -- The first thing you do when you arrive on site is to inform those in charge that you are there and that there is a real possibility that the alarms will sound off. Never sugar-coat the explanation, it always is a possibility. Let management know that sounding off the alarms can't always be helped, but you are going to try to prevent that from happening...
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Will a Trouble on a Device Sound the Alarm? -- Do you mean by Alarm Signal, a Fire Alarm that gets everybody out of the building, shuts doors, shuts down the air handlers, stops industrial processes, etc.? The answer to what happens when an input or output device goes into trouble is a little less clear...
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Is it possible the door holder relay is breaking down? -- A door holder circuit system has four major parts: - The Power Supply with its Breaker and the Main Distribution Board Breaker - The Wiring in the Building along with other equipment in the building attached to the power supply - The Door Holder Electromagnet - The Door Holder Relay ...
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How do magnetic door locks work when a fire occurs? -- How do magnetic door locks work when a fire occurs & a signal goes from fire control panel through a relay contact? -- Magnetic Door Locks and Magnetic Door Holders work the same way. When power is applied to the door lock or door holder, the electromagnet is turned on and keeps the door locked or the door held open. Once a fire alarm occurs, the fire alarm panel sends...
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I'm Having Trouble With a Door Release -- While trying to trouble shoot why the door release for the front door is not working, one of the conductors grounded out against the fire alarm panel chases. This caused the door release to activate. Any thoughts?
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Who do I Call to Reset the Duct Detector in my RTU? -- The fire alarm people are experts on smoke detection, including duct detectors. These are the people who can help reset the duct detectors, or replace the duct detectors if they're faulty. First, though, you can at least try to reset the duct detectors yourself by shutting off the power to the RTUs for about 5 seconds and then turning the RTUs back on. If that fails to start up the RTUs, or if the RTUs stop after a short while, call the fire alarm installation company...
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Is There a Procedure to Install EST Detectors? -- I have an EST3 fire alarm system. Is there any procedure to install heat detectors and multi-sensor detectors? After fixing how many smoke detectors, can we install heat detectors or multi-sensor detectors? ---- Fire alarm systems are Detect and Warn systems. If the detectors on any type of fire alarm system are changed...
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How do you Troubleshoot an Addressable System? -- No matter what the panel says, or what a multimeter says, all faults are either an open or a short. Both causes could be in the building wide fire alarm system at once, and there may be more than one problem to contend with. Shorts could be inside a device, in the building wiring, or in the panel- opens could be inside a device, in the building wiring, or in the panel. A ground fault is a short, and ground faults require two shorts in order for a ground fault to affect the fire alarm system. At all times when troubleshooting, keep an open mind. Never assume that you know what the problem is until the problem is fixed...
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What is the Difference Between a Fire / Smoke Damper and a Fire Damper -- The first answer is that a FSD is a Fire/Smoke Damper that closes with either fire or smoke, and the Fire Damper closes only with fire and stays open with smoke. There are similarities and differences between them. Either one can be manually reset or automatically reset (opened). In essence, it's inside the damper that the detection takes place. A fire damper closes when heat from a fire is detected at the damper, smoke damper closes when smoke is detected inside the air duct at the damper, and a fire / smoke damper closes when either smoke or heat is detected...
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Do We Have to Replace the Entire Panel? -- Panel works fine, all components, until there is a drop in electrical current or the panel loses power completely. There are two battery back-ups, 12v 7Ah each, but for some reason it doesn't seem to help. We also tested it by shutting the ...
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I Need to Replace and Old Fire Alarm Panel -- Looking for a upgrade from a old fire alarm panel to a more modern model. The building is 3 floors with 8 suites and has magnetic door latches that are released when there is a heat detector or pull station in use. The old fire panel was made in 1987. What make and model of fire alarm panel would be able to work with the existing conventional heat & smoke detectors ...
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How do I Connect an FM200 System to the Fire Alarm System? -- It looks like you have two totally separate fire alarm systems - the EST system and the FM200 system. Each one has its own detection system, horns and strobes, and actions that they take when they have an alarm.The EST system doesn't tell the FM200 system to do anything. When there's an alarm on the EST system, the FM200 system doesn't do anything or display...
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How Can I Find this Intermittent Ground Fault? -- A ground fault is an electrical leakage to building ground on a fire alarm system. The ground faults are most commonly in the wiring. Devices themselves, unless there's water damage, are usually electrically isolated so they won't be the cause of a ground fault. The ground fault shown on the panel can be caused by...
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How Can a Door Holder be Hot and Buzzing? -- You describe two problems. The door holders are hot and the door holders buzz. Two types of electrical power could be used for the door holders, AC and DC. Some of them are AC only, some of them are DC only, and some of them can be either AC or DC. Usually the rating is stamped on the door holder assembly somewhere.
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How do I Cause a Trouble on a NAC Circuit? -- When the Notification Appliance Circuit, or NAC Circuit, is being supervised, the horns and strobe don't have any current running through them - it's only the wires of the NAC Circuit that are being supervised...
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How is the Sensitivity of a Smoke Detector Determined? -- To determine how much smoke it takes to set a smoke detector into alarm, sensitivity testing uses a calibrated, portable cloud chamber. It uses a photo-reader, kind of like the smoke sensing chamber inside a photo smoke detector, to sense the amount of smoke in the cloud chamber. The cloud chamber, or testing tool, completely encloses the smoke detector and starts out with clean air. For the measurement, artificial calibrated smoke is slowly introduced into the chamber...
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How Do I Shut Down Auditorium Sound on Fire Alarm? -- I have an auditorium that needs to have the sound shut down when the fire alarm is activated. The sound board or DSP (Digital Signal Processing) has an emergency input that I can connect to, but the prints are engineered to use the SLC loop to shut it down ...
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How are NAC Circuits Activated by the Panel? -- Simply said, to sound the alarm, the fire alarm panel -in a Conventional System- turns on the fire horns and strobes on a Notification Appliance Circuit (NAC) by turning on the power -in the alarm voltage polarity-; to check the wires (Supervise the Wires) when the panel is not in alarm, the fire alarm panel is constantly..
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How Do I Connect Two Fire Alarm Panels Together? -- Whether it is one addressable and one conventional panel, or two panels of any sort, there is one issue that has to be dealt with before anything else is taken care of. The issue is that someone untrained and not you are not going to be there to reset the system when there is a false alarm. This is a given, and this is the problem that has to be addressed when using two panels to cover the same building...
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Is There a Method for Testing Fire Alarm Systems? -- The Fire Alarm and Detection System (FDAS) detects fire and warns people of the fire. Because the system detects fires, it also compartmentalizes the building by closing fire doors, controls smoke by shutting down ventilation systems, controls access to areas of the building, and sends for help from the fire department. The FDAS (Fire Alarm and Detection System) also supervises other...
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How do I Test Devices Using a Multimeter? -- You can use an ohmmeter on a conventional pull station to see if it shorts out the wires when it's activated. However, to see if activating the pull station will send an alarm to the fire alarm panel and sound the alarm, the only way to test it is to wire it into the fire alarm system, and by activating the pull station, use it to try and sound the alarm. An ohmmeter doesn't show anyone whether...
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How Do You Troubleshoot a Shorted NAC? -- First off, we have to understand what a NAC (Notification Appliance Circuit) is: it's the wiring outside the fire alarm panel that goes to the horns and strobes, (the notification appliances - the devices). The circuit is a pair of wires that connects all the devices in a chain fashion, like a single strand of beads on a necklace. ...
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I have Mechanical Room PIV Error -- An addressable panel, like the Siemens panel you're working on, uses a Signaling Line Circuit (SLC) for communication. This is really a computer data and power buss. This circuit ...
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I'm Looking for a Fire Alarm System -- I am looking to purchase a complete fire protection system for a Power Plant. I have searched and found some of the big names in fire alarm such as XXX Manufacturing, YYY Manufacturing, ZZZ Manufacturing, Etc...
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Do You Use Normally Open Contacts for Alarm Circuits? -- When a wire breaks, or comes loose from a connector, the circuit has opened up. But just because a wire came loose from a connector in a fire alarm system, it is not a good idea to sound a fire alarm. A false alarm will evacuate a building, and call the...
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What is the Typical Clock Rate of an SLC? -- There is no such thing as a typical clock rate. Each manufacturer uses a different baud rate, voltage, and data-protocol on their SLC circuits. To make it even more complicated, many manufacturers use several different baud rates, voltages, and data-protocols...
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Can I Reset a Smoke Detector using Magnets? -- For test purposes, the first detector sets the panel into alarm, but the next detector tested will not set the panel into alarm because the panel is still in alarm. If you are testing just the smoke detectors and want to know whether they...
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How do I Find this NAC Trouble? -- The panel is looking at voltage on the NAC circuits - you need the meter to see the voltage that the panel is seeing. When there's no fire alarm on the NAC circuit, there are three voltages possible: Normal, Shorted, Open. These are relative voltages and the only way of telling if the voltage is correct is to compare the NAC 2 voltage to the NAC 1 voltage...
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Is There a Code Saying the NAC Can't be in Conduit with the SLC? -- The contractor wants to run the NAC and SLC circuit in the same conduit distance is about 13 feet. Is this allowable? Or must the two circuits be in different conduits? I looked in NFPA 2016 Chapter 12 and found nothing prohibiting running them together. However, my colleague said it is not permissible but he didn't tell me what reference in the code dictates this. What am I missing?...
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Why Won't the Horns and Strobes Work? -- When running the continuity check, the panel has to send voltage out on the wires. However, the horns and strobes can't be sounding off. To solve this, the panel reverses the polarity on the circuit to make sure the horns and strobes can't sound off when they aren't supposed to...
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Why reverse polarity for fire alarm horns? -- A fire horn is turned like a light; it turns on when power is applied and turns off when power is removed. But then again, to constantly check continuity of the wires (supervise the wires), the Fire Alarm Control Panel (FACP) always has power applied to the circuit.
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Why reverse polarity for fire alarm horns? -- A fire horn is turned like a light; it turns on when power is applied and turns off when power is removed. But then again, to constantly check continuity of the wires (supervise the wires), the Fire Alarm Control Panel (FACP) always has power applied to the circuit.
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Is it Permissible to Connect Addressable Devices in a Class A System? -- Notification Appliance Circuits (NAC) whether they're Class A or Class B have to be consistent. All of the horns, strobes, and any speakers on the circuit have to be of the same manufacturer, and work with each other in the circuit; they have to be compatible with each other. If they are of different types, some of the horns or strobes won't sound off at the proper rate, and possibly won't work at all. Some of the speakers will be either too loud or too quiet. When addressable horns, strobes, and speakers are on the same circuit as...
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How do I Fix an Open Fault? -- The fire alarm system is supposed to consist of the wiring in the building, all of the input devices -smoke detectors, pull stations, waterflow switches, etc.- and all of the output devices -fire horns and strobes, etc.- Between all of the input zones and output zones is a control panel. There should be an end-of-line resistor at the end of each loop -the pair of wires connected to a zone and connected to all of the devices on the zone-...
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What Causes an Open NAC? -- I am going to a job site where on the service call ticket states that a NAC is reading open circuit. What can cause an open circuit on the NAC line?
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What Causes an Open NAC? -- I am going to a job site where on the service call ticket states that a NAC is reading open circuit. What can cause an open circuit on the NAC line?
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Phone Line Troubles Keep Waking Me Up! -- Every month between the last day of the current month and the 5th of the next month I receive phone line failures on my fire panel. It's clockwork. The troubles resolve shortly after the 5th of each month. The phone service goes "in and out" and the phone company can never find the problem and the fire panel technician can never find a problem. Of course, I am the one losing the sleep...
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What is the Difference in Power Supplies? -- What is the difference between an auxiliary power 24-volt connection from the control panel and other additional power 24-volt power supplies like the booster power supply? -- It doesn't matter whether the power supply is in the fire alarm control panel, or in a different box somewhere else, no power supply produces power; all power supplies only convert power. They require utility power (120 or 230 volts AC) and convert this utility power to the 12 volts or 24 volts DC that the fire alarm system uses. This includes the Auxiliary Power Supplies and the Booster Power Supplies (BPS)...
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Am I Allowed to Power Up on the Battery? -- Powering up a panel using only battery backup is a manufacture's design issue. Some manufacturers have fail-safe features that prevent a panel from turning on until utility power is applied; some manufacturers don't bother with the fail-safe features and allow the panel to be powered up using the batteries...
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Should a Battery Backup be 5 or 15 Minutes? -- There are two things to consider when deciding whether it's 5 minutes of evacuation, or 15 minutes of evacuation. One consideration is what building is going to be used for (its occupancy), and the other is what kind of fire alarm system is going to be needed for the occupancy ...
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Why Won't the Strobes Work? -- When there's an alarm, all the horns sound off, but none of the strobes flash. Can you help me or give me suggestions on how to fix this? I've never run into this problem before. I would like to have at least some ideas of what to look for. G D. There are several possible causes for the problems, Compatibility Issues, Signal Power Expander or Booster Power Supply, Polarity Issues, Voltage Drop Issues. Compatibility. The requirement that all strobes in an area flash at the same time requires that the manufacturers all come up with a method of synchronizing the strobes. This synchronization is to prevent...
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Is This an Addressable 4 Wire Speaker/Strobe? -- A speaker and a strobe are always separate devices. Many times, as with the speaker/strobe that you show, the speaker and the strobe my be in the same box, but they are still separate devices, they aren't connected together inside. In this case, this is not an addressable device. On the back of the speaker / strobe, there are 4 terminals: 2 of the terminals are for the speaker and two of the terminals are for the strobe. In other words, the terminals aren't for a single 4 wire addressable circuit, but the terminals are for two completely separate 2 wire circuits: 2 of the wires are for powering the strobe and 2 of the wires are for powering the speaker...
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When Testing, Why Isn't the LED Lit Continuously? -- First off, that blink you are seeing on the smoke detector is the time that the fire panel is communicating with that particular detector. Normally, every 5 seconds or so the panel is checking with each detector and module in the system to make sure all are connected, and to receive any alarms or troubles in the system. This check of the detector every 5 seconds is called...
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Why Don't All of the Smoke Detectors Act the Same? -- When testing, not all of the SDs are behaving in the same way, some of the SDs are only generating the alarm in the panel without latching the LED light. I've checked for ground faults. There was a panel negative earth leakage, but it has been fixed. The Signaling Line Circuit (SLC) power supply polarity of all the SDs re-checked. The panel was re-started. Unfortunately, some of the smoke detectors are still not latching in alarm....
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How Can I Clear the Trouble Tone? -- I have a trouble message. How can I clear the trouble tone? - - The trouble light and trouble tone are on the fire alarm system as a warning: Something's Not Working. As long as something's not working on the fire alarm system, the trouble light is going to stay on...
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How do I Troubleshoot Analog Addressable Systems? -- The systematic approach to troubleshooting an Analogue Addressable Fire Alarm Loop is exactly the same as troubleshooting any problem with any fire alarm system. Remember, all fire alarm systems have devices in the building, all fire alarm systems that have a display have a control panel, all fire alarm systems use wires to connect everything together...
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How do I Find the Ground Fault? -- Normally, nothing else in the entire fire alarm system, anywhere in the building, is supposed to be connected to the metal of the building. That means that there is no complete electrical path from the power supply of the fire alarm panel, through the circuitry with the devices, to building ground, and back to the panel's power supply through its ground fault detection...
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How do I Get This Tamper Switch to Work? -- The cover is on the right-hand side and uses a tamper-resistant screw to stay closed. Once the cover is removed, it should be obvious how the plug can be reinserted. Until that extra cover is removed, and the mechanism is reset inside it, the tamper switch will continue to send a Supervisory Signal back to the fire alarm control panel...
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What Wiring Method Should I use for Speakers? -- Whether it's going to wind up being a Class A or Class B wiring method for the speakers, whether it's going to be a conventional speaker circuit or addressable speakers, the method of a installing voice evacuation speaker system is first determined by the absolute minimum standards shown in the NFPA. Greater requirements can be indicated by any of the AHJs...
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When are voice evac systems required? -- In many cases, a fire alarm system is no longer just a fire alarm system. Voice Evacuation is allowing Mass Notification to be used over part of the fire alarm system to announce to the occupants what to do for other emergencies. In other words, an FAS (Fire Alarm System) doesn't just function as an FDAS (Fire Detection and Alarm System) but as a Fire Detection and Emergency Announcement System...
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When are voice evac systems required? -- In many cases, a fire alarm system is no longer just a fire alarm system. Voice Evacuation is allowing Mass Notification to be used over part of the fire alarm system to announce to the occupants what to do for other emergencies. In other words, an FAS (Fire Alarm System) doesn't just function as an FDAS (Fire Detection and Alarm System) but as a Fire Detection and Emergency Announcement System...
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What Voltage Should Be at the EOL of a NAC? -- The goal, when measuring the voltage on the Notification Appliance Circuit -NAC-, is to make sure that there is enough voltage to turn on all the horns and strobes when there is a fire. The power may be off to the building during a power blackout, but the voltage still has to be there for the horns and strobes to warn people of fire...
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What are the Signals on the SLC? -- I would like to know what type of signal is there between addressable fire detectors and the fire alarm monitoring panel. Actually I want to know how the address / location of...
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What Causes a Fire Alarm System Trouble? -- The word Trouble on a fire alarm system means -In the Fire Alarm System, including all the Input and Output Devices, Signal and Power Wiring, and Panels, something is not working correctly-. This is based on the absolute need for the fire alarm system to Detect Fire and Warn People of Danger. A trouble can be caused by...
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What is Causing a Network Fault? -- A Network Fault is a problem (Trouble) with the fire alarm system. The fault has to be fixed before it can be cleared from the panel. To clear the trouble from the display, there's also a trouble memory that requires the troubles to be acknowledged and cleared after fixing the trouble...
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What Voltage Should I Measure on the NAC? -- I have been trying to find a voltage spec for the voltage reversal signal that typically comes out of a fire panel. I have seen somewhere that is normally +24v and -24v when reversed. Elsewhere, I see that its +24v when in alarm and "some negative voltage" when ....
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Who is Supposed to Remove an Old Fire Alarm System? -- Rather than relying on anyone else to remove an old fire alarm system so a new fire alarm system could be installed, the company I worked for always removed the no-longer-used-fire alarm system. As far as the National Fire Protection Association (NFPA) goes, however, even having a fire alarm system in the first place is the owner's responsibility. The owner only uses a fire alarm company for installation, testing, servicing, and replacement of the fire alarm system. As well as removing any old panels, devices, and wiring...
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Why Aren't There a Lot Of Troubles When Removing Wires? -- I have a question about a fire alarm circuit and I hope you will help me out. When I remove one positive wire from a smoke detector, I don't see it and any other loop devices missing in my trouble log, except the device I took off and a Style 6 Loop trouble. My question is, shouldn't I get a list of all devices which are connected in loop? For example, if I remove one positive wire from the Loop 3 smoke detector Number 34, I am receiving a "No Response Smoke Detector 34" and "Style 6 Loop3 Trouble" Why am I not getting a list of all of the devices that are in trouble? ...
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Help! I Have Some Weird NAC Troubles -- A booster panel feeding unit strobes in a condo building will go into trouble only at night. The troubles occur between the hours of about 1am to 6am and then never have an issue at any other time of day. The booster clicks in and out of trouble very quickly while this is happening...
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Why Won't the Added Horns and Strobes Work? -- We attempted to add two horns and 2 strobes to the NAC circuit by extending the circuit and relocating the EOL resistor to that new end of line. When we did this, we get a trouble light. The cause of the trouble that has been isolated by troubleshooting to the NAC circuit. The new added strobes had a different power level than the ones already there, so we ordered identical ones. Still having the trouble light lit on the panel. Any suggestions?
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What is an As-Built Plan? -- The owner of the building project is the beginning of the planning process and the end of the planning process. Conception Plans - How the building ...
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How do Pathways Affect Ground Faults? -- Ground Faults are a big issue. Almost anytime there is a ground fault on a fire alarm system, the panel displays a trouble. Then, no matter what caused the trouble, the trouble has to be fixed. However, the NFPA has an exception to the rules regarding the displaying of ground fault troubles. For all types of pathways for signal or power in building wide fire alarm systems, the rule of thumb for displaying a ground fault trouble goes something like this, -Whenever there is a ground fault, the panel will display a trouble.- There is an exception to this rule ...
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Horns and Strobes for Handicap Apartments -- Multifamily dwellings like apartments, condominiums, hotel rooms, etc., actually have two fire alarm systems: each individual residence's fire alarm system and the building's common fire alarm system. A fire alarm system, any fire alarm system, detects ...
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Why Do We Inspect Fire Alarm Systems? -- A long time ago, before regular testing of fire alarm systems was required, the NFPA and other fire protection professionals discovered that large numbers of fire alarm systems just weren't working... at all. Originally, when they were installed, these systems worked properly ...
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It's just one more strobe, what's the problem? -- Sometimes, after a building has been established for years, the fire marshal or the building owners want to add another horn or strobe. Or maybe, with remodeling, more horns and strobes are just added to an existing Notification Appliance Circuit (NAC). Really, it is just one more strobe and the circuit works...
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Troubleshooting Addressable Ins and Outs -- A fire alarm system's main purpose is to detect fire and then tell people about the fire. A conventional fire alarm system does this detection-telling, and so does an addressable fire alarm system. Besides a better display on the addressable fire alarm system and the extension of the ...
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Why is Snow White? --
Question: If the sun is yellow, why is snow white?
Answer: Because the Sky is Blue. Um, the riddle seems to be nonsense, but really...
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