Hilchos-Rosh Hashonah [When to Light]
- There are two Minhagim when to light on the first day of Yom Tov. Some light before Yom Tov like on Shabbos and some light before the meal.
- It is preferable to light before Yom Tov.
- The Minhag is that women say Shecheyonu when they light.
- If you lit before Yom Tov and made Shecheyonu you are not allowed to do anything that is not permitted on Yom Tov. It does not help to make a Tenai (you can not light and not be Mekabel Yom Tov because you said Shecheyonu).
- This Halocho applies by Yom Kippur also.
- Therefore if you are planning to drive to Shul after lighting you should not say Shecheyonu when lighting and make a Tenai that you are not being Mekabel Yom Kippur with the lighting.