Before You Begin Installing
151068
3-9
3.9.3
Current Draw Worksheet
Use this worksheet to determine current requirements during alarm/battery standby operation.
(Copy this page if additional space is required.)
*Note:If you are using door holders, you do not need to consider door holder current for alarm current because
power is removed during that time. However, during normal operation, door holders draw current and
must be included in the total standby current that can be drawn from the panel.
Note: Total standby current must not exceed maximum Battery standby load listed in Table 3-5.
Table 3-6: Current Draw Calculations
Device
Number of
Devices
Current per Device
Standby
Current
Alarm
Current
For each device, use this formula:
This Column X
This column
=
Current per number of devices
SK-4224 Panel
1
Standby:
65 mA
65 mA
Alarm:
250 mA
250 mA
A
Current Subtotals:
65 mA
250 mA
Smoke Detectors
Refer to device manual for current ratings. See Appendix to this manual for
max. # per loop.
Standby:
mA
mA
Alarm:
mA
mA
Standby:
mA
mA
Alarm:
mA
mA
Standby:
mA
mA
Alarm:
mA
mA
Standby:
mA
mA
Alarm:
mA
mA
B
Current Subtotals:
mA
mA
Notification Devices
Refer to device manual for number of devices and current ratings.
Alarm:
mA
mA
Alarm:
mA
mA
Alarm:
mA
mA
Alarm:
mA
mA
C
Current Subtotals:
mA
mA
Accessory Devices
SK-2884
Standby:
10 mA
mA
Alarm:
10 mA
mA
SK-2866
Standby:
35 mA
mA
Alarm:
85 mA
mA
SK-2880
Standby:
35 mA
mA
Alarm:
660 mA
mA
SK-2104
Standby:
33 mA
mA
Alarm: 70 mA (while dialing)
mA
D
Current Subtotals:
mA
mA
*Additional Devices
Standby:
mA
mA
Alarm:
mA
mA
Standby:
mA
mA
Alarm:
mA
mA
E
Current Subtotals:
mA
mA
F Total current rating of all devices in system (add TOTALS OF A-E) X .001:
A
A
G Number of standby hours. (24 or 60 for NFPA 72, chapter 1, 1-5.2.5):
H
H Multiply lines F (standby current) and G:
Total standby AH
AH
I Alarm sounding period in hours. (For example, 5 minutes = .0833 hours)
H
J Multiply lines F (alarm current) and I:
Total alarm AH
AH
K Add lines H and J. (AH = Ampere Hours)
Total AH required
AH
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