Trouble Circuit Wiring
- Thread starter tpepperl
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- Massachusetts
I generally follow the manufactures instructions. :grin:
My Two cents.
My Two cents.
A trouble is not really a zone type. You would not program a zone, or device to display trouble when the device goes off normal.
Trouble signal definition from NFPA 72 2010 3.3.240.7: A signal initiated by a system or device indicative of a FAULT in a monitored system, or component.
Note FAULT. Fault is not defined in there However, a fault would be a wiring problem, or device in a faulted condition. This is different from a off normal condition, such as a tamper switch that has be activated. Now, if you were monitoring the trouble output of a device or system (think dry contact output), this should not be programmed as a TROUBLE zone. This zone can go into trouble, when there is a FAULT in wiring associated with it. Or:
Some will wire the zone normally closed and have the device open the circuit to cause a trouble signal. This is misleading. If you are remotely monitoring the signals, you would see a trouble. Until you actually inspect the device you do not know if the device is actually in trouble/off normal OR there is a problem with the circuit itself.
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Now, If I were to wire a circuit that required tamper, or another non-alarm condition I would wire it Normally Closed with a resistor (Form A).
As long as it is not a latching device, this allows for a sort of fail safe scenario. I would try to be consistent on the job. All my alarm points would be normally open with resistor in series, and all my non-alarm points normally closed with resistor in parallel.
This will not work in all situations, but IMHO, is a best practice.
My Two cents.
A trouble is not really a zone type. You would not program a zone, or device to display trouble when the device goes off normal.
Trouble signal definition from NFPA 72 2010 3.3.240.7: A signal initiated by a system or device indicative of a FAULT in a monitored system, or component.
Note FAULT. Fault is not defined in there However, a fault would be a wiring problem, or device in a faulted condition. This is different from a off normal condition, such as a tamper switch that has be activated. Now, if you were monitoring the trouble output of a device or system (think dry contact output), this should not be programmed as a TROUBLE zone. This zone can go into trouble, when there is a FAULT in wiring associated with it. Or:
Some will wire the zone normally closed and have the device open the circuit to cause a trouble signal. This is misleading. If you are remotely monitoring the signals, you would see a trouble. Until you actually inspect the device you do not know if the device is actually in trouble/off normal OR there is a problem with the circuit itself.
------
Now, If I were to wire a circuit that required tamper, or another non-alarm condition I would wire it Normally Closed with a resistor (Form A).
As long as it is not a latching device, this allows for a sort of fail safe scenario. I would try to be consistent on the job. All my alarm points would be normally open with resistor in series, and all my non-alarm points normally closed with resistor in parallel.
This will not work in all situations, but IMHO, is a best practice.
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It does not matter if it is addressable or not.
NFPA 72 Section 6.8.5.11.1 States "Automatic fire suppression system alarm-initiating devices and supervisory signal-initiating devices and their circuits shall be designed and installed so that they cannot be subject to tampering, opening, or removal without initiating a signal.".
Inorder to achieve this if your NAC Booster, VESDA panel, or any other fire alarm device has removable terminals the only way that you can ensure that "a signal is generated" is by wiring the circuit normally closed with a resistor in series.
Wiring the device normally open with a resistor in parallel will not "generate a signal" when the connector is removed from the system.
Hence the question? What is the right way to wire it and comply with NFPA 72?
NFPA 72 Section 6.8.5.11.1 States "Automatic fire suppression system alarm-initiating devices and supervisory signal-initiating devices and their circuits shall be designed and installed so that they cannot be subject to tampering, opening, or removal without initiating a signal.".
Inorder to achieve this if your NAC Booster, VESDA panel, or any other fire alarm device has removable terminals the only way that you can ensure that "a signal is generated" is by wiring the circuit normally closed with a resistor in series.
Wiring the device normally open with a resistor in parallel will not "generate a signal" when the connector is removed from the system.
Hence the question? What is the right way to wire it and comply with NFPA 72?I misspoke. I did not read the OP correctly, I was mixing fire alarms and burglar alarms in post #4.
All of my fire alarm wiring is NO with a EOLR.
So a short prior to the EOLR is required to generate an alarm or supervisory signal and an open prior to the EOLR would generate a trouble signal.
This is just common sense.
All of my fire alarm wiring is NO with a EOLR.
So a short prior to the EOLR is required to generate an alarm or supervisory signal and an open prior to the EOLR would generate a trouble signal.
This is just common sense.
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