Edwards Signaling FIRE ALARM EQUIPMENT Design Guide

FIRE ALARM EQUIPMENT

System Design Criteria

Initiating Devices

When 2-wire ionization and/or photoelectric smoke detec­tors are incorporated into an alarm system, you must en­sure that the detector standby current (of any combination
of detectors), does not exceed the allowable total standby
detector current per zone of 1500 microamps. Normally­open devices, such as manual fire stations, automatic
heat detectors and waterflow switches require no standby
current, and therefore can be installed in any quantity
required.

Current Alarm

Cat. No.* Detector Type Standby Req. Current

SC10U Ionization 50 microamps 100mA
SC30U Photoelectric 62 microamps 100mA

*2-wire application

Operation of a manual station, automatic heat detector or
waterflow switch on the same zone as smoke detectors
will prevent the operation of smoke detectors on that
zone.

To determine the maximum n umber of Edwards smoke
detectors that can be connected to each alarm initiating
circuit, total the smoke detector standby current require­ments of all detectors . The following table and example
may be utilized as a reference:

Example:

Qty. Detector Type Microamps

20 SC10U Ion Detectors 20 x 50 = 1000
18 SC30U Photo Detectors 18 x 62 = 1116

Total microamps = 2116

Signaling Appliances

When any combination of Edwards signaling appliances
(horns, strobes, horn/strobes, bells) is used, the total sig­naling current requirements for the panel must not ex­ceed as follows:

NAC/Pwr Aux Pwr

Cat. No. Description Outputs Output

E-FS101* FireShield 1 zone 1.0A 0.5A

E-FS302* FireShield 3 zone 1.5A 0.5A

E-FS502* FireShield 5 zone 2.5A 0.5A

E-FS1004* FireShield 10 zone 2.5A** 0.5A

EBPS6 6.5A Booster Panel 6.5A Tot. 2; 3 A

EBPS10 10A Booster Panel 10.0A Tot. 2; 3 A

*Add "G" for gray cabinet or "R" for red cabinet

**Expandable to 5.0A with Cat. No. XTR3A-120 Transformer

To determine the maximum number of signaling appli­ances that can be connected to the signaling circuit, total
the signaling appliance alarm current requirements of all
signaling appliances. See the below examples and appli­cable catalog pages as a reference:

Qty Cat. No. Type mA Total Current

3 2447TH Horn 20 3 x 20 = 60 mA
4 2452THS-15/75-R Horn/Strobe 225 4 x 225 = 900 mA

Total Signaling Current 960 mA

© Copyright 2004 Edwards

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