LV-8A
Low Voltage Power Distribution Module
The LV-8A distributes power from a low voltage power source to 8 individually fused
outputs. Ideal for providing distributed power to CCTV Cameras, Security System
Components, Motion Detectors, Exit Buttons, etc.
Two terminals are provided for each output. Two terminals are provided for input
power from a user-supplied low voltage power source up to 30V (AC or DC).
The LV-8A uses standard 3AG type fuses ordered separately depending on individual
output device current requirements. Heavy duty wire clamp-type captive screw termi-
nals are utilized for #14-24AWG wiring.
The module is 2.75" wide x 7.00" long. The installed height with relay is 1.20". Stand-
offs are included for mounting the circuit board in a user-supplied enclosure.
* * * WARNING * * *
Turn off all power feeding the module terminals before servicing or changing
input/output wiring, removing or reinstalling fuses, etc. Failure to observe this
warning may cause electrical shock hazard or may damage internal or external
circuit components.
The information in this manual is believed to be accurate in all respects. However, BASE Electronics cannot
assume responsibility for any consequences resulting from the use thereof. The information contained herein is
subject to change and BASE Electronics may issue a revision to incorporate such changes at any time.
INSTALLATION
Locate the unit inside an enclosure close to the source power supply. Drill (4) 0.187"
diameter holes to match the (4) corner holes in the printed circuit board. Push the
nylon standoffs supplied into each hole and snap the module into place.
NOTE: For UL installations, locate the unit inside a UL Listed NEMA 1 enclosure
such as a BASE LVPC Low Voltage Power Cabinet.
POWER SUPPLY WIRING
Connect the low voltage power supply input leads to the terminal strip at the bottom
side of the circuit board as shown in Figure 1. Use a minimum of 18AWG copper
conductors for this wiring and keep the length to the power supply as short as pos-
sible.
V = +DC or one side of low voltage AC
C = DC Common or the remaing side of low voltage AC
OUTPUTS AND CONTROLS
NOTE: The maximum recommended operating current at any single LV-8A output
should not exceed 2.5 Amperes. The maximum recommended total operating current
(all output currents added) should not exceed 8 Amperes.
Suggested wiring methods are shown in Figure 1. Wiring to the output devices con-
nects to the Output terminals. Two terminals are provided for each LV-8A output.
V = the fused output terminal (+ when using a DC Voltage)
C = the voltage Common terminal
Add the expected operating current ratings for each device to be powered from one
LV-8A output to determine the expected operating current flow. Install a fuse for the
output that will trip when this value is exceeded. The value of the fuse selected for
each output may be written on the white area below the fuse for easy future reference.
Example A: Output 1 - (1) magnetic lock
operating current = 0.29A at 12 VDC
Install fuse rated just greater than 0.29A = 3/8A or 1/2A
Example B: Output 2 - (4) deadbolt locks
operating current = (4 x 0.40A) = 1.6A
Install fuse rated just greater than 1.6A = 2A
When powering devices over considerable distances, the cabling resistance may be so
high that the voltage available at the device drops to an unacceptable level. To pre-
vent this from occuring, the system cabling should be designed with adequate sized
conductors. Use the Low Voltage System Cabling Design Guide in this manual for
help in obtaining the desired results.
LIGHTNING, TRANSIENT AND NOISE SUPPRESSION
Lightning or transient suppression devices may be installed at the LV-8A output ter-
minals to protect control equipment from induced voltages. A multi-screw, solid ground
bar should be installed vertically next to the output side of the module for connection
of metal oxide varistors, transient suppression diodes, etc. If shielded cable is used for
output wiring, shield drain wires can be connected to the ground bar for line noise
suppression. Run a minimum #14AWG green stranded ground wire from the ground
bar to the closest Service Ground. Grounding bars of the type mentioned above can be
separately supplied by BASE Electronics.
LOW VOLTAGE SYSTEM CABLING DESIGN GUIDE
With an improperly designed cabling system, the resistance of wire conductors may
cause a voltage drop that could significantly affect the performance of the powered
device. The resistance of a given length of cabling and its voltage drop at the given
operating voltage can be calculated. This allows the affect on the powered device to
be estimated with adjustments in conductor size implemented in the design stage.
Example:
A CCTV camera requires 0.29A at 24 VAC and the estimated cable length from the
power supply is 800 feet. The camera specifications state that the camera will operate
properly down to 21.0 VAC (a voltage drop of 3.0 volts maximum). What should be
the size of the power cable conductors? From the chart below, we observe that a pair
of 18AWG stranded copper conductors will have a resistance of 2 x 800 feet x 6.48
ohms/1000 feet. Using Ohm's Law: E = I x R
E (voltage dropped) = I (the required current) x R (the cabling resistance)
E = (0.29) x (2 x 800 x (6.48/1000)) = 3.007 volts
Subtracting 3.007 volts from 24VAC leaves 20.993 volts available at the camera, an
unacceptable level. When 16AWG conductors are used in the equation: E = (0.29) x
(2 x 800 x (3.67/1000)) = 1.703 volts
Subtracting 1.703VAC from 24VAC leaves 22.297VAC available at the camera. Tak-
ing future expansion of a second camera into account, the estimator may decide to
increase the conductors to #14AWG as follows:
E = (2 x 0.29) x (2 x 800 x (2.31/1000)) = 2.14VAC dropped
When powering inductive devices (relay coils, electric strikes, magnetic locks, etc.),
remember to install reversing diodes (DC powered) or metal oxide varistors (AC pow-
ered) at the device terminals or as recommended by the device manufacturer to counter
the affect of Counter Magnetic Force (CMF).
Resistance of Copper Conductors
Solid Conductors Stranded Conductors
Wire Gage Resistance Wire Gage Stranding Resistance
(AWG) (Ω/1000') (AWG) (#/AWG) (Ω/1000')
10 1.00 10 37/26 1.11
12 1.59 12 7/20 1.45
14 2.53 14 7/22 2.31
16 4.02 16 7/24 3.67
18 6.39 18 16/30 6.48
20 10.15 20 10/30 10.32
22 16.14 22 7/30 14.74
24 25.67 24 7/32 23.30
