“This provision names the law and explains when it starts”
This law is called the Electricity Act 1992. You can think of it as a set of rules about electricity that came into effect in New Zealand.
Most of this law started working on 1 April 1993. However, some parts of it began earlier. These earlier parts started the day after the Governor-General signed the law to make it official.
The law has different sections that deal with various things related to electricity. Some of these sections, like Part 1 and Part 4, started right away after the law was signed. Other parts, like sections 63 and 64, also began immediately.
There are a few exceptions to when the law started. Sections 54(2) and 56(2) have their own special start dates, which are different from the rest of the law.