They are the weakest link and will release the chain if pulled too hard. They keep you from breaking the original chain, some of which goes inside of the fan and very time consuming to fix.
The links are separated by insulating material so there will be no electric shock hazard to a person pulling the chain if the chain happens to contact an energized electric wire.
You need to rewire to a lower voltage at panel or get a transformer that steps down 277 to 110 volts. Make sure wire is sized for new load as well as breaker.
If the question is, can I wire a switch to an existing light fixture (and I must assume that it's something like a pull-chain light fixture), the answer is yes. If the question is, "how do I wire a...