LV-8RCL
Low Voltage Power Distribution Module
The LV-8RCL distributes power from a low voltage power source to 8 fused outputs
through 8 Output Isolation Relay sockets. Terminals are provided for control of each
output relay by an Access Control system. Output devices can be powered separately
from the control relays by configuring Common Power Jumpers. A 2-pole Disconnect
Relay socket is provided and easily interfaces with Fire, Life Safety or Alarm Panels to
provide Emergency Power Disconnect. Relay auxilary contact terminals are provided
for alarm monitoring of the Disconnect feature.
Each model includes jumpers configurable for 3 modes of operation:
1) 8 outputs that are disconnected by the Disconnect Relay
2) 8 outputs that are unaffected by the Disconnect Relay
3) 4 x 4 mode (Outputs 1-4 = Mode 1, Outputs 5-8 = Mode 2)
The LV-8RCL includes red LED indicators at each of the 9 relay positions for iden-
tification of energized relays.
The module is 5.00” wide x 8.00” long. The installed height with relays is 2.50”.
Standoffs are included for mounting the circuit board in a user-supplied enclosure.
Relays and 3AG-type Fuses are provided separately. To meet UL Listing require
-
ments, the relays selected should be Idec Corp., P/N RH1B-U SPDT or P/N RH2B-U,
DPDT, 12vdc or 24vdc.
* * * WARNING * * *
Turn off all power feeding the module terminals before servicing or changing input/output wiring, removing
or reinstalling fuses or relays, or cutting jumpers. 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 a NEMA 1 enclosure (such as a BASE LVPC Low Voltage Power
Cabinet) 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.
POWER SUPPLY WIRING
Common Relay Control and Output Voltage If the output devices require a DC
operating voltage, the Common Power Jumpers can remain intact and only one DC
power supply needs to be connected to the PWR input terminals. In this mode, the
DC operating voltage of the control relays, output devices and the power supply must
match. Example: Output devices = 24VDC Maglocks, Power Supply = 24VDC,
Relays must be 24VDC.
Separate Relay Control and Output Voltage
By cutting the Common Power Jumpers, two separate power supplies of like or dif-
ferent voltages can be used to power the output devices (use the PWR terminals) and
control relays (use the CTL terminals). The CTL power supply must be DC while the
PWR power supply can be either AC or DC.
Connect the power supply input leads to the terminal strip at the lower left side of the
module 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 possible.
MODE CONFIGURATION
Each module includes 8D and 4X4 jumpers for configuring the mode of operation.
Continuous Power Mode
When no jumpers are cut, the outputs are continuously
powered and unaffected by the Disconnect feature. If Emergency Power Disconnect
is not needed, do not cut any jumpers and do not install a 2-pole relay at the Discon-
nect Relay socket.
8 Disconnect Mode
When the 8D jumper is cut, all 8 outputs will be disconnected
by the Disconnect Relay when the Fire Panel Interface control circuit is opened. A
2-pole Disconnect Relay must be installed in the socket provided.
4 X 4 Mode
When the 4 X 4 Jumper is cut, outputs 1-4 will operate in the Disconnect
mode and outputs 5-8 will be unaffected by the Disconnect feature. A 2-pole Discon
-
nect Relay must be installed in the socket provided.
POWER DISCONNECT WIRING
A socket is provided for a 2-pole relay that is used to disconnect the output power PWR
during facility emergencies. The relay is DC powered from the power feeding the CTL
terminals. Normally closed dry contacts of a fire or life safety system panel are used to
control the disconnect relay at the ‘F’ terminals. The alarm contact should be rated for
the current required by the relay selected (normally less than 50mA at 12VDC).
The auxiliary output contacts of the Disconnect Relay can be monitored. Note that the
terminals designated NO and NC (shown in Figure 1) stand for Normally Open and
Normally Closed when the relay is de-energized. The terminal marked ST is a Spare
Terminal available for termination of an end-of-line resistor if needed.
OUTPUTS AND CONTROLS
Add the operating current ratings for each device to be powered from one 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
Add the operating current ratings for each control relay and install a control fuse that
will trip when this value is exceeded. The value of the fuse selected may be written
on the white area below the fuse for easy future reference.
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
prevent 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. Wiring to output devices connects to the OUTPUTS
terminals. Three terminals are provided for each output. ‘NC’ or ‘NO’ designates the
fused output terminal. ‘Com’ designates the voltage Common terminal. Suggested
wiring methods for OUTPUTS and CONTROLS are shown in Figure 1.
LIGHTNING, TRANSIENT AND NOISE SUPPRESSION
Lightning or transient suppression devices may be installed at the LV-8A output terminals to protect control equip-
ment 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. Taking 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 powered) 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
