16
Wire Splicing
Wire splices must be kept to a minimum. Every splice increases the
conductive resistance, reducing the effective distance of the electrical
power or signal. Also, every splice is a potential failure point for the
system due to the danger of corrosion in the wire, improper joint
connections, radio frequency interference, ground faults, and other
factors. Improper splices run the risk of intermittent system problems
that can be very difcult to troubleshoot. Try to plan and install the
site so that the only splices in the system occur in the terminal blocks
that connect to each AI device. If a splice is absolutely necessary,
it must be done in an above-ground, weatherproof, electrical-rated,
junction box. The proper procedure for making a wire splice is as
follows:
1. Inside the junction box, pull an extra foot of
wire for each side of the splice. This is called
a service loop and allows extra wire for future
service or replacement of the splice if it is
done incorrectly, becomes corroded, or is
otherwise damaged.
2. Trim back 1½ inches of the outside insulation
jacket on the cable. Do NOT strip the
insulation off the individual conductor wires
themselves. Place the two wires to be spliced
side by side and twist them together for about
½ inch, leaving about 1 inch of wire free to be
slid into a 3M U-Type connector. 3M U-Type
connectors can be purchased from PTI
Security Systems.
NOTE: Do not leave copper wire exposed. The outside sheathing is necessary
for the strength of the connection.
Never splice two
different colors, gauges,
or types of wire. It is extremely
important that wire color, gauge,
type, and purpose of each wire
remain consistent throughout a
site.
For example: If you are following
PTI Security Systems’ wiring
recommendations, the DC+ wire
should be red, 18 AWG stranded
copper wire throughout the site.
Never pull spliced
wire through conduit.
Splices should only be made in
wire that is already pulled into a
junction box.
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