Ash-Shaykh Muhammad bin Saalih al-Uthaymeen rahimahullah, said:
الحال الأولى: أن ينوا الإقامة المطلقة في بلاد الغربة ، كالعمال المقيمين للعمل ، والتجار المقيمين للتجارة ، وسفراء الدول ونحوهم ممن عزموا على الإقامة ، إلا لسبب يقتضي نزوحهم إلى أوطانهم ، فهؤلاء في حكم المستوطنين في وجوب الصوم عليهم ، وإتمام الصلاة الرباعية
“The first scenario: If they were to make an intention to generally reside in a foreign land similar to the state of those employed who are residing [at a foreign place] for the purpose of work and similar to the state of business men who are residing for business transactions and the state of embassadors for certain countries and the likes of them whom have decided to reside [therein], except in the case that necessitates them returning to their lands. Therefore, their ruling is the ruling of people of residence wherein regards to fasting being obligatory upon them and in regards to completing the four unit prayer…”
[Majmoo’ul Fataawa Ibn Uthaymeen (15/289)]
The Lajnah ad-Da’imah stated:
You must offer Salah in full during your stay in your working place, because you intend to stay more than four days whether you are staying alone or with your family. Therefore, the rulings of a traveler are not applied to you or your teaching colleagues. It is Mustahab (desirable) for you to offer the Sunnah Ratibah.
May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.
Also Ash-Shaykh Bin Baaz rahimahullah mentioned the same applies for a person who has two places of residence; a place of residence for work and a place of residence with family. He is regarded as being a resident in both residences.
This is likewise the opinion of Shaykh Albany rahimahullah.
A Side Note: However, it is permissible for him to shorten and combine his prayers during his travels between both places [i.e. place of work and place of residence] if it is travelling distance or for a person who is on a business trip and he doesn’t know when he will return to his land.
AbdulFattaah Bin Uthman