Wire Specification Guidelines The wire should meet the following specifications.
· Stranded · Unshielded (except when two separate data loops share the same conduit). Note: ZONEX 1 and ZONEX 2 are separate data loops, and each is separate from data loops that support command centers, printer modules, etc.
Three loops connected to the same D8125 POPEX module are not separate data loops.] ·
Twisted (6 twist per foot) ·
Mid Capacitance (30 to 40 Pico-farad per 1,000 feet) ·
1 ohm per 1000 feet ·
16 to 22 AWG (18 AWG recommended) ·
PL (Power Limited wiring for burglary) ·
FPL (Fire Power Limited for fire)
Wire Type Summary Typical installations of digital data use mid-capacitance wire. ·
Burglary applications: Mid capacitance, low resistance, unshielded twisted pair stranded wiring is used. ·
Fire applications: Mid capacitance, low resistance, unshielded, twisted solid wiring has been required. Beginning in August of 1998, NFPA-72 now sanctions the use of stranded wire on fire system data loops. However, ultimate approval still rests with the local fire AHJ. ·
Low capacitance wire is recommended for excessively long wire runs.
Calculating Capacitance Formula The formula for calculating capacitance is: One Micro-Farad = .000001 [one-millionth of one] farads of capacitance. One Pico-farad = .000000000001 [one-trillionth] farads of capacitance. Example: A single 1,000 foot data loop was run with wire rated at 20 Pico per foot: Add up the totals for all system data loop pairs to determine total system capacitance. Capacitance Graph (Read as if these were golf scores; lower number is better.) Shorts to Conduit Other wires in the same conduit (any extra inductor) will absorb energy and increase capacitance. (Feet of wire x capacitance [Pico per foot]) x .000001 [one micro-farad] = Total in micro-farads 1,000 feet x 20 Pico per foot = equals 20,000 Pico-feet, 20,000 x .000001 (one Micro-farad) = .02 micro-farads [mF] for the single wire pair. Low Capacitance 20 pf per foot Shielded 12 pf per foot Unshielded Mid Capacitance 30 pf per foot 20 pf per foot.
NOTE: Avoid wire nuts or wire crimps. These are not recommended for Digital Data Circuitry as they may create an "Antenna" effect.
Other Things to Consider · If shielded wire must be used, connect one end of the drain wire to the panel’s Earth Ground Terminal [not to a common] only. Tape the drain wire at all other points (POPIT’s, J-boxes) to keep it from touching water or metal, as two ground references on the same drain wire effectively create a ground loop antenna, which attracts RFI (noise) that can and will corrupt the Point Bus data.
Documentation identifying the location of all POPITS on each data loop can save hours of troubleshooting time. If that isn’t possible, at least try to identify and document the last point number (located the longest data distance from the POPEX module) on each pair. ·
Always mark the wires, and use colors consistent with NEC-70 and the application for that wire. Exterior Insulation Jackets or Twisted Pairs · Grey/Brown/White/Beige: Burglary ·
Red/Clear Plenum: Fire Conductor Insulation · Red Conductor: Positive (+) Voltage Power · Black Conductor: Negative (-) Voltage Common ·
Yellow: Data Out (Zonex Out) from the Panel ·
Green: Data In (Zonex In) to the Panel Conductors ·
Copper: Positive (+) · Silver: Negative (-) Use an audio amplifier to determine noisy hot spots before mounting the panel enclosure and running data wire. Do not use existing wiring unless you have verified its integrity with the Wire Validation Worksheet.
Very hot D8125 ceramic resistors and/or ‘runaway missing’ indications mean that there are sustained shorts on the loop/restore reports from the panel. Shorts need to be checked from point to point. Disconnect the point midway on the loop, then measure resistance in both directions; continue this process on the portion of the data loop on which resistance is noted, until the lowest resistance reading leads you to the short. Ensure that two loops running parallel do not have continuity between them by disconnecting both loops and checking for resistance between the two.
Use the following to confirm the maximum data loop distance, based on wire gauge (assumes maximum number of POPITS for the panel that is connected).
22 awg 1800 ft
20 awg 2890 ft
18 awg 4600 ft
16 awg 7320 ft
14 awg 11650