I'm just speaking for myself here... but for low level AC (signal), I've been using some 24 AWG solid core twisted pairs cut out of some balanced interconnect cable I bought on sale awhile back. It's nice stuff...solid silver conductors, teflon insulation... blah blah. Overkill but I have a roll so I use it. High level AC (speaker), I currently have stranded 16 AWG tinned copper with some kind of waxed cotton insulation, again using what I have around. Low level DC (separate front end power and ground) I use 18 AWG stranded tinned copper. High level DC (amplifier board rails and ground) I use 16 AWG stranded tinned copper. I can usually find a roll of discarded multi conductor cable laying around at work (railroad industry) that I cut the sheathing off of and extract the individual wires. The stuff we have is always high quality USA made Belden, Carol, Alpha, etc... For mains wiring, and circuit ground > CL-60 > chassis, I think it's just more of the same 16 AWG stuff.
I use a wide variety of wire in the pursuit of money and prefer stranded wire in most cases. I'm swimming in solid UTP network cable (almost all systems these days reside on their own network or hang off of another one) and will use it for signal level runs in projects that will be closed up, put to use and not moved constantly. In any installation less stable than a house, I also like to secure the conductors near the point of connection if possible. I prefer 24ga. stranded network cable for the added resiliency and I absolutely cannot hear a difference between the two. Most people have loads of unused patch cords and I imagine you do too.
I use Cl2/Cl3 stranded cable in 16, 18, 20, 22ga. for almost everything else audio hobby wise because its on the shelf and works. Marine cable is nice too... Fine Strand tinned copper with a tough heat resistant jacket and its available in small spools at any boat shop/chandlery/globalmegaretailer.
Other wiring best practices as it pertains to amplifiers and whatnot. 1) physically pull on any conductor terminated in a screw terminal to verify that the resistance you're feeling is due to a good connection and not a thread or connector issue. The resulting high resistance connection can range from a sometimes difficult to track gremlin to a structure fire if any real energy is involved.
2) do not secure stranded wire in a screw terminal without a pressure plate. If the terminal uses nothing more than a bare screw, get a better terminal.
3) search fu a "Chassis wiring ampacity table". I couldn't care less if someone wants to wire their FW power rails with 2/0
too many people confuse NEC allowable ampacities as a golden rule that applies everywhere. I'll go ahead and drop that graphic here.
Adding 4) Shrink tube is super useful not only to cover a connection but as protection around sharp panel edges or other points of contact. Also, color coding usage in a busy enclosure helps during troubleshooting/modification/repair. The adhesive shrink tube is worth a little extra, not necessary for this work but I prefer it. Buy a few colors, develop or use a consistent color code and don't forget the clear... its handy sometimes. Cheers
I use Cl2/Cl3 stranded cable in 16, 18, 20, 22ga. for almost everything else audio hobby wise because its on the shelf and works. Marine cable is nice too... Fine Strand tinned copper with a tough heat resistant jacket and its available in small spools at any boat shop/chandlery/globalmegaretailer.
Other wiring best practices as it pertains to amplifiers and whatnot. 1) physically pull on any conductor terminated in a screw terminal to verify that the resistance you're feeling is due to a good connection and not a thread or connector issue. The resulting high resistance connection can range from a sometimes difficult to track gremlin to a structure fire if any real energy is involved.
2) do not secure stranded wire in a screw terminal without a pressure plate. If the terminal uses nothing more than a bare screw, get a better terminal.
3) search fu a "Chassis wiring ampacity table". I couldn't care less if someone wants to wire their FW power rails with 2/0
too many people confuse NEC allowable ampacities as a golden rule that applies everywhere. I'll go ahead and drop that graphic here.
Adding 4) Shrink tube is super useful not only to cover a connection but as protection around sharp panel edges or other points of contact. Also, color coding usage in a busy enclosure helps during troubleshooting/modification/repair. The adhesive shrink tube is worth a little extra, not necessary for this work but I prefer it. Buy a few colors, develop or use a consistent color code and don't forget the clear... its handy sometimes. Cheers
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As I am more of a subjective guy than objective, someday I may be compelled to try different cables for say the speaker out to speaker posts. Up until a few years ago I hadn't heard solid core speaker cable that I liked, now....very much. That being said, the above advice seems pretty sound considering the short runs inside the equipment, and yes I have a collection of nice cables 
Based on the table I see two columns for ampacity and I'm hoping to get some clarity.
Can someone explain the nuances between the "chassis wiring" and "power transmission". Is power transmission out in the open "room", like a power cord? Does AC mains inside the chassis count as power transmission, or chassis wiring?
There's definitely a big difference in the ampacity allowance between the two columns.
Can someone explain the nuances between the "chassis wiring" and "power transmission". Is power transmission out in the open "room", like a power cord? Does AC mains inside the chassis count as power transmission, or chassis wiring?
There's definitely a big difference in the ampacity allowance between the two columns.
Power transmission ratings are not applicable here. AC mains cables are for power transmission. There are no enforceable requirements or official published "best practices" that concern the construction of projects discussed here.
Marine wise, there's the ABYC standards which, while written in the same style as the NEC are merely unenforceable suggestions although they're widely adopted within the industry.
The chassis ampacity ratings are considered conservative and are used to size single, unbundled wires at relatively short lengths. You'll notice it's quite vague... don't trouble yourself over defining a bundle or looking for deratings tables. 3,4,5 loosely twisted conductors that aren't contained within conduit aren't a heating concern or hazard in any other sense. When in doubt calculate your voltage drop, set a reasonable threshold (5%) that you're comfortable with and have fun. Remember, the NEC is a product of the NFPA, is about life safety and applies to practically every electrified structure, wiring method and use case out there. Yachts, RVs, cars and utility service facilities excepted. Imagine, 3 12ga cables in a closed conduit, each safely carrying their full rated 30A for 150+'. The requirements are built largely around the heat produced in that environment, jacket temp and composition.
A 15" 18ga wire loosely run across an amp enclosure with 12-15A peaks looks quite reasonable
Marine wise, there's the ABYC standards which, while written in the same style as the NEC are merely unenforceable suggestions although they're widely adopted within the industry.
The chassis ampacity ratings are considered conservative and are used to size single, unbundled wires at relatively short lengths. You'll notice it's quite vague... don't trouble yourself over defining a bundle or looking for deratings tables. 3,4,5 loosely twisted conductors that aren't contained within conduit aren't a heating concern or hazard in any other sense. When in doubt calculate your voltage drop, set a reasonable threshold (5%) that you're comfortable with and have fun. Remember, the NEC is a product of the NFPA, is about life safety and applies to practically every electrified structure, wiring method and use case out there. Yachts, RVs, cars and utility service facilities excepted. Imagine, 3 12ga cables in a closed conduit, each safely carrying their full rated 30A for 150+'. The requirements are built largely around the heat produced in that environment, jacket temp and composition.
A 15" 18ga wire loosely run across an amp enclosure with 12-15A peaks looks quite reasonable
I prefer wire with Teflon (PTFE) insulation. It doesn’t melt at soldering temperatures.
CAT6 twisted pair is excellent for signal wiring from the input connectors to the channel boards.
I use Teflon insulated 16ga for the high level wires to the speaker connectors. Aerospace grade tin plated.
The remaining wires are whatever I have lying around. 18ga is quite sufficient for AC on the primary side of the power transformer.
CAT6 twisted pair is excellent for signal wiring from the input connectors to the channel boards.
I use Teflon insulated 16ga for the high level wires to the speaker connectors. Aerospace grade tin plated.
The remaining wires are whatever I have lying around. 18ga is quite sufficient for AC on the primary side of the power transformer.
