Question: I'm replacing the wiring from a vintage chandelier and need to know what gauge wire to use. There are five lights on it. This is for the fixture only!

Answer: 
18g stranded wire is [quite common on arms](http://www.thisoldhouse.com/toh/photos/0,,20267510_20599803,00.html)
14g stranded is often used to join the 18g arm strands, and to tie into the ceiling.

This applies to North America and normal chandeliers with relatively low (<50 each) wattage bulbs.
Agree 18 awg for the arms and 16 awg is desirable for a splice if needed to feed the ceiling junction box although 18 awg could be used by code as long as the total current stays below 6 amps. House wiring must be at least 14 awg or larger. The thinner gauge 18 and 16 awg is allowed because the wiring is not buried in a wall and is not adjacent to flammable materials. It must be "fixture wire" with quality high temperature insulation; doorbell or speaker wire is not likely to have this type of insulation.