Owner`s manual

PAGE 22 Community Solutions™ Owner’s Manual
10 ELECTRICAL INSTALLATION
10.1 Loudspeaker Cable / Wiring
To get the maximum performance from your loudspeaker, proper 2 conductor wire and good quality
connectors must be used. The most important factor in selecting wire is its resistance which is
primarily a function of wire gauge and length. It is desirable to keep the total resistance under 0.2
Ohm for any wire run to the speaker to maximize electro-mechanical damping and minimize power
losses. However, for lengths over 100 feet the wire gauges needed to meet this requirement are
usually not practical to use for both physical and cost reasons. Therefore #10 AWG is recommended
as the most practical gauge for those situations. TABLE 5 shows the minimum wire gauges to use for
various wire lengths for 4 Ohm or 8 Ohm loudspeakers. For each run length both conductors has been
figured into the total resistance. Note that the lower the gauge number the larger the wire size.
Run Length Minimum
Gauge (AWG)
Total
Resistance
10 ft (3 m) #16 0.08 Ohm
25 ft (8 m) #14 0.13 Ohm
50 ft (15 m) #12 0.16 Ohm
75 ft (25 m) #10 0.15 Ohm
100 ft (30 m) #10 0.20 Ohm
200 ft (60 m) #10 0.40 Ohm
300 ft (90 m) #10 0.60 Ohm
400 ft (120 m) #10 0.80 Ohm
500 ft (150 m) #10 1.00 Ohm
Note – Metric length conversions are approximate
Table 5: Loudspeaker Wire Selection
In permanent installations, speaker wire is usually permanently fixed in place. Therefore it is not
necessary nor economical to use cable intended to be flexed such as for portable use. PVC jacketed or
similar, multi-conductor cable is easy to work with and more economical. Among the best and most
economical wire is standard copper electrical wire such as stranded or solid THHN or THWN. The only
difference between these two types is the voltage rating of the insulation. THHN is rated for 300 volts
and THWN is 600 volts. Both ratings far exceed the voltage output of even the most powerful audio
amplifiers. These are also among the most familiar wire types for electricians to pull in conduit.
For portable applications use stranded copper cable designed for flexing with a tough overall
insulation. For good flexing, the conductors should each have a minimum of 19 strands for #14 or
#16 AWG and 65 strands for #10 or #12 AWG. Hypalon™, and polyethylene insulations can provide a
complete combination of good electrical properties, abrasion resistance, low temperature flexibility, as
well as water, sun, oil, and chemical resistance. Other insulations such as rubber, neoprene, and
polypropylene are lacking in one of more of these qualities and should be selected based on the
intended environment and use.
In environments that have extremely high amounts of radio frequency (RF) energy, such as near radio
transmitting towers, it may be necessary to use shielded speaker cable to reduce interference.
Normally the shield is connected only at the amplifier end to the chassis of the amplifier or other
suitable system grounding point. The wire gauge recommendations in the above chart should still be
followed.