How long should there be between the first and second adhaans for Jumu‘ah?
Question

How much time should there be between the first and second adhaans for Jumu‘ah?
Praise be to Allah.The amount of time that there should be between the first and second adhaans for Jumu‘ah is as much as is sufficient for the people to get ready for Jumu‘ah prayer and come to the mosque. This was enjoined by ‘Uthmaan ibn ‘Affaan (may Allah be pleased with him) during his caliphate, when the numbers of people in Madinah increased. He instructed someone to give the call from a place in Madinah called az-Zawra’, so that the people could be alerted and stop their buying and selling and other worldly activities, and get ready to come to Jumu‘ah prayer.
The second adhaan is to inform people that the time for the prayer has begun, and is given when the imam enters the mosque and sits on the minbar, as was done at the time of the Prophet (blessings and of Allah be upon him).
Thus we know that the purpose of the two adhaans is that the first adhaan is to alert the people to go to offer the Jumu‘ah prayer, and it is given earlier so that the people will be able to prepare themselves and go to the mosque early for Jumu‘ah prayer. The purpose of the second adhaan is to inform the people that the time for the prayer has begun, and it is given when the khateeb arrives and sits on the minbar, as was done at the time of the Prophet (blessings and of Allah be upon him).
There must be some time between the two adhaans so that the first one will serve a purpose. As for following the first adhaan immediately with the second, with only a short time in between, as is done in some countries, this defeats the purpose of the first adhaan, and this is not what ‘Uthmaan (may Allah be pleased with him) intended when he enjoined it, as it is of no benefit.
Al-Muntaqa min Fataawa ash-Shaykh Saalih al-Fawzaan (2/101).