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Fire Alarm -- Description

The panel can not tell when part of the buildings fire alarm system does not work if the wires are not supervised or continually checkded for continuity.
Supervision: If the wiring isn't supervised (continually tested for continuity by the panel), how can the panel tell the owner of the building (go into trouble) if a wire comes loose preventing the life safety fire alarm system from working?
Douglas Krantz -- Fire Alarm Engineering Technician, Electronic Designer, Electronic Technician, Writer






Why Does the Fire Alarm Panel Supervise the Wires?

By Douglas Krantz

Supervision of building wiring isn't really to make sure the wires are good, supervision of building wiring is to make sure all the devices are connected.

I know, everyone, including me, talks about making sure the wires aren't broken. However, the concern isn't about the wires. It's the input and output devices of the fire alarm system that is being worried about: whether the devices are able to communicate with the fire alarm panel.

Conventional Supervision

On conventional fire alarm systems, the devices are simple and don't have a way of saying that they aren't working. However, as far as the devices themselves go, the fire alarm system should be on a regular testing program to make sure the devices work.

But even when the devices function properly, in order to be of any good, they still have to be connected to the fire alarm panel. That's where wiring supervision comes in; to make sure that all of the devices are connected, at least the wires are supervised.

Wiring Supervision

If a smoke detector is removed, the wiring no longer passes current and supervision says to the panel that there is a problem with the wiring; interpretation - - devices aren't connected.

If a fire horn is removed, the wiring no longer passes current and supervision says to the panel that there is a problem with the wiring; interpretation - - devices aren't connected.

If a wire is broken somewhere in the building, the wiring no longer passes current and supervision says to the panel that there is a problem with the wiring; interpretation - - devices aren't connected.

Yes, to say that there is a problem with the wiring, these are the troubles that show up on the panel. The real reason, however, that those troubles show up on the panel, is that there is a good probability some or all of the devices on the loop are not able to communicate with the panel; interpretation - - for those areas of the building, the fire alarm system doesn't work.

Device Communication

So the real issue here is not a problem with the wiring, per say; the real issue here is that devices are not able to communicate with the panel, and as a whole, the fire alarm system is compromised.

More Articles

Why is Supervised Wiring So Important? -- Based on Life Safety considerations, supervision makes the difference between building low voltage wiring and building fire alarm system wiring... Read More

How Do You Troubleshoot Using Supervision Voltage? -- With Fire Alarm Systems , one method of troubleshooting is measuring supervision voltage . It's the voltage at the panel's IDC input terminals (Initiating Device Circuit for... Read More

How Are Fire Alarm Loops Supervised to Make Sure They Continue to Work? -- Because the fire alarm system is a Life Safety System (people's lives depend on the fire alarm system working in an emergency), using supervision, the panel makes sure the field devices are always... Read More

What is Fire Alarm Class B Wiring? -- Fire alarm people are paranoid. They're afraid everything is working against them. They're in fear that that if anything goes wrong... Read More



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