According to PA DOR - https://revenue-pa.custhelp.com/cgi-bin/revenue_pa.cfg/php/enduser/std_adp.php?p_faqid=205&p_created=1038892541&p_sid=Kmh*16qi&p_lva=&p_sp=cF9zcmNoPTEmcF9zb3J0X2J5PWRmbHQmcF9ncmlkc29ydD0mcF9yb3dfY250PTQwNCZwX3Byb2RzPSZwX2NhdHM9MTMsMCZ wX3B2PSZwX2N2PTEuMTMmcF9zZWFyY2hfdHlwZT1hbnN3ZXJzLnNlYXJjaF9ubCZwX3BhZ2U9Mg**&p_li=&p_topview=1

Fees for labor are taxed when the labor is expended on a taxable item i.e., repairs to a vehicle. (The vehicle was a taxable item, hence labor to repair it is taxable.) This would also apply to appliances, jewelry, and any other taxable items.

Labor charges to install or repair items that become part of real estate are not taxable. This would include installation of such items as a water heater, boiler, or new roof.

https://revenue-pa.custhelp.com/cgi-bin/revenue_pa.cfg/php/enduser/popup_adp.php?p_sid=Kmh*16qi&p_lva=&p_li=&p_faqid=641&p_created=1043272640&p_sp=cF9zcmNoPTEmcF9zb3J0X2J5PWRmbHQmcF9ncmlkc29ydD0mcF9yb3dfY250PTQwNCZwX3Byb2RzPSZwX2N hdHM9MTMsMCZwX3B2PSZwX2N2PTEuMTMmcF9zZWFyY2hfdHlwZT1hbnN3ZXJzLnNlYXJjaF9ubCZwX3BhZ2U9Mg**

The following applies only when a construction activity is performed for a non-exempt entity. When a contractor attaches or affixes tangible personal property to real estate so as to become a permanent part thereof. Construction activities also include the service of repairing real estate even though tangible personal property is not transferred by a contractor in conjunction with the repairs which he makes.

The contractor would pay tax on any materials transferred to the customer. He would not collect tax from his customer. The tax that he pays is an expense that he would include in his cost of the materials.

In the absence of satisfactory evidence to the contrary, the following items are presumed to become a permanent part of real estate:
.......
Cabinets (attached by screws or fasteners and the like)
..........
Because kitchen cabinets are attached to the real estate - installation labor is not taxable.