Is there a way to have your 240 central ac unit circuit double as a regular outlet in winter time for use in christmas decorations
What you could do is install a small sub panel at the end of the wires. Install an additional 240 volt breaker, same amperage as the breaker feeding the AC unit and a 120 volt, 15 or 20 amp breaker for the outlets. This requires that you have 4 wires feeding it, two hots, a neutral and a protective earth. If you only gave three wires (no neutral) you’ll need two 240 volt breakers and a step-down transformer to get the 120 volts.
You would need a converter to go from 240 to 120 and then you could.
Check out this post Replacing 240V outlet with 120V. It'll give some ideas.