Question:
Does cutting the nails or having a hair cut while in wudû' make wudû' invalid?

Answer:
Cutting nails and having a hair cut are not prohibited at any time except while a person is in the state of ihrâm during Hajj or `Umrah.
In no case do these activities invalidate a person's wudû’.
And Allah knows best.
Responded by: Sheikh `Abd al-Wahhâb al-Turayrî, former professor at al-Imâm University in Riyadh