What is the ampacity of 14 gauge silver wire?
In general the current rating of a wire is limited by the wire's ability to dissipate heat to its surroundings without getting too hot. That in turn depends on the maximum safe wire temperature and the thermal resistance to ambient. Unfortunately figuring out exactly what the thermal resistance to ambient is for a given installation method is nontrivial.
Unfortunately standards don't normally say how they came up with the tabulated figures but one can assume they were determined from experimental data.
We can come up with a figure for a silver wire by assuming that the acceptable heat dissipation for a silver wire of a given size is the same as that for a copper wire of the same size. We divide the resistivity of silver by that of copper and then take the square root (remember \$P=I^2R\$).
Using numbers from this table tells us that a silver wire should have about 1.03 times the current carrying capacity of a copper wire of the same size installed under the same conditions.
This is small enough that other factors (exact installation method, material purity, how the material was worked into a wire etc) are likely to outweigh the difference between silver and copper.
Other than material and gauge, ampacity is limited by insulation temperature rating, maximum ambient temperature, bundling (how many other wires, and how much current are they carrying) and by altitude and the anticipated installation conditions. A PTFE-insulated wire that is allowed to run at 180°C will carry a lot more current safely than one that is only allowed to run at 105°C, especially if the ambient temperature is high (the ratio increases as the maximum ambient temperature increases and becomes infinite at the ambient equal to the lower rated wire).
So basically just use tables for copper of equivalent insulation under the equivalent conditions and you'll be "about right" and slightly on the safe side. Silver wire may not be approved for residential electrical wiring, aircraft use, or other specific applications, however, so keep whatever standards you may have to meet in mind.
If it's speaker wire there are no standards as far as I'm aware, nor do you typically have ampacity issues. We used AWG8 silver-plated copper conductors deep inside very expensive plastic molds (think 2l pop bottles- but at the preform stage, not the blow molding). The wire was MIL-spec not UL.
Bare wire is another thing altogether. The "fusing current" for silver is about 75% of that of copper of equivalent diameter, based on the ratio of fusing constants.
You won't find an answer easily because it depends on many other factors as well. The ones listed for copper are usually standards for use in construction.
The current carrying capability of a wire depends on, amongst other things:
- The operating conditions of the wire
- The allowed maximum voltage drop across the wire for a given current
- The maximum temperature the wire is allowed to reach because of either safety concerns (it might cause damage or risk starting a fire if it gets too hot) or the temperature the insulation can handle without melting.
There may be additional factors, such as the environment of the cable. For example, if the cable is to be used in a large harness with many others, it will be able to carry less current as it will have a harder time getting rid of heat because of the other cables (that might also be getting warm). Hence, the current that cable may carry could be significantly lower than what it can carry when suspended in the air on its own.
Long story short: You can't find any information because it depends, and in addition, I have never really heard of anyone using solid silver as conductor.