Sending blessings upon the Prophet (peace and blessings of Allaah be upon him) when the iqaamah is pronounced
Question

                When the iqaamah is pronounced the muezzin says, “Allaahumma salli ‘ala Muhammad wa ‘ala aalihi wa sahbihi wa sallim, Allaahu akbar Allaah akbar (O Allah, send blessings and peace upon Muhammad and upon his family and companions, Allaah is Most Great, Allaah is Most Great).” Is this Sunnah?.
Praise be to Allah.It is obligatory upon the one who wants to do any act of worship to learn the rulings on it and how it is to be done from the Sunnah of the Prophet (peace and blessings of Allaah be upon him), so that he will not be worshipping Allaah in ignorance. For Allaah should not be worshipped except in the manner that He has prescribed. Whoever worships Allaah in a manner that has not been prescribed by Allaah and His Messenger (peace and blessings of Allaah be upon him), it will be rejected and will not be accepted, because the Prophet (peace and blessings of Allaah be upon him) said: “Whoever does an action that is not in accordance with this matter of ours (i.e., Islam) will have it rejected.” (Narrated by Muslim, 1718). 
The bid’ah that has been introduced to the iqaamah for prayer is that which has been mentioned in the question, whereby the muezzin sends blessings upon the Prophet (peace and blessings of Allaah be upon him) before pronouncing the iqaamah (call immediately preceding the prayer). This action is bid’ah (an innovation) that was not done by the Prophet (peace and blessings of Allaah be upon him) or by any of his companions. 
Shaykh Jamaal al-Deen al-Qaasimi stated that it is bid’ah in his book Islaah al-Masaajid min al-Bida’ wa’l-‘Awaa’id, p. 134.