For safety,
pool lights are almost always 12v. It is illegal (in South Africa) to install one in a pool, if the Voltage it operates on is more than that.
Normally there is a transformer in the Pool DB or Box, that steps the voltage down from Mains to 12vAC. Then the 12v goes to the pool fitting, that (might have) a Bridge Rectifier or Diodes to convert from AC to DC...