Sayyed Mohammad Al-Musawi, Sayyed Mohammad al-Musawi is originally from Iraq and heads up the World Ahlul Bayt Islamic League in London. Other than being involved in various humanitarian projects, he frequently responds to... Answered 1 year ago

If the long nails stop water from reaching to any part of the hand which must be washed in Wudhu, it will then cause the Wudhu to be invalid. But if you ae sure that water is reaching to every part of your hand which must be washed in Wudhu, then you have no problem.

It is better to avoid long nails as it can cause some times preventing water from reaching and if such thing happens, the Wudhu will be invalid.