Parallel Wires
Is it possible to combine several lengths of wire in parallel to produce a larger wire gauge? The answer is “yes” if done with care. Here are the specifics.
A recent SynAudCon Listserv thread raised an interesting and practical topic. The question posed to the group was whether one could combine several lengths of wire in parallel to produce a larger wire gauge. The answer is “yes” if done with care. Here are the specifics.
The resistance of a conductor is inversely proportional to its area – the larger the area the lower the resistance. Figure 1 shows the resistance per unit length for copper wire. The American Wire Gauge AWG is given, as is the area.
When two conductors of equal area are paralleled, the resistance is halved. Each halving of resistance increments the wire gauge by 3 sizes. So, two 18 conductors parallel will produce an AWG 15 conductor. The conductors should be run in close proximity to reduce inductance, and care should be taken to properly identify them at each end.
Audio/Acoustical consultant David Wright offered some insights:
We routinely ask for dual cable runs per bass driver in the main cluster, for several reasons.
- 1. It lowers effective wire gauge and improves damping. We calculate that two 14AWG (WP226) dual runs on a bass driver is equivalent to about an “11 AWG” cable run.
- 2. More importantly, it builds in the potential for biamping in the future if there is a budget crunch that forces us to use a passive cabinet now. The cable is already there.
- 3. Also, it allows an economy for the contractors. They don’t have to switch to “another” cable number or type in a division 16 format bid package with their submittals or electrical prime. It lowers potential confusion as a result. Their submittal legends are simpler, their electrical contractor doesn’t have to figure a separate run of 10 or 12 AWG. He just has to add more runs of the what is more likely on the job anyway (14 AWG). Also, the AV contractor purchasing agent stocks less cable, and he orders less variety. And he can more readily use 14 AWG tail or left overs on other jobs.
M. David Wright, C.T.S, ASA