Employees whose work means that they have to continue working at the time of Jumu’ah

The basic principle is that Jumu’ah prayer is obligatory upon individuals, because Allaah says (interpretation of the meaning): 

“O you who believe (Muslims)! When the call is proclaimed for the Salaah (prayer) on Friday (Jumu‘ah prayer), come to the remembrance of Allaah [Jumu‘ah religious talk (Khutbah) and Salaah (prayer)] and leave off business (and every other thing). That is better for you if you did but know!”

[al-Jumu’ah 62:9]

And Imam Ahmad narrated from Ibn Mas’ood (may Allaah be pleased with him) that the Prophet (peace and blessings of Allaah be upon him) said concerning some people who were failing to attend Jumu’ah prayers: “I had thought to tell a man to lead the people in prayer, then I would burn down the houses of men who fail to attend Jumu’ah prayers.” (Ahmad, 1/402; Muslim, 1/452). Muslim narrated from Abu Hurayrah and Ibn ‘Umar (may Allaah be pleased with them) that they heard the Messenger of Allaah (peace and blessings of Allaah be upon him) say from the minbar: “There are people who should stop neglecting Jumu’ah, or else Allaah will put a seal on their hearts, then they will surely be among the negligent.” And there is consensus among the scholars on this point (that Jumu’ah is obligatory). But if a person for whom Jumu’ah is obligatory has a legitimate shar’i excuse – such as one who is directly responsible for a matter of national security and protecting the interests of the ummah, and he is required to do that job at the time of Jumu’ah, such as those who are in charge of security, traffic, wireless and telephone communications, etc, those whose shift happens to be at the time of the second call to Jumu’ah prayers or the time of a prayer in congregation – then such people are excused for not praying Jumu’ah or prayers in congregation, because of the general meaning of the verse (interpretation of the meaning): 

“So keep your duty to Allaah and fear Him as much as you can”

[al-Taghaabun 64:16]

And the Messenger of Allaah (peace and blessings of Allaah be upon him) said: “Whatever I forbid you to do, avoid it, and whatever I command you to do, do as much of it as you can.” Moreover, such a person has no less an excuse than one who is excused because he fears for his life or his wealth etc., who the scholars have said is excused for not praying Jumu’ah or prayers in congregation so long as the reason is present. But the obligation to pray Zuhr still stands, and he must pray it on time; whenever he can pray in congregation he is obliged to do that, as is the case with all the five daily obligatory prayers.