Bolts used for photovoltaic (PV) assembly are typically specialized to meet the specific requirements of solar panel installation.  Here are some common types of bolts and fasteners used in PV assembly:

T-bolts: These bolts are used with T-slot rails for mounting solar panels onto the rack system.  They have a T-shaped head that fits into the slot of the rail for easy installation and adjustment.

Hex Head Bolts: These are standard bolts with a hexagonal head and are used for securing various components of the solar panel mounting system.

Lag Bolts: Lag bolts are heavy-duty screws with a hex head and are used to secure the mounting structure to the roof or ground.  They provide strong anchoring for the solar panel system.

Flange Bolts: These bolts have a wide flange under the head that distributes the load and helps prevent pull-through in softer materials.  They are commonly used in solar racking systems.

Bonding Bolts: These bolts are used for grounding purposes to ensure electrical safety in the PV system.  They help create a continuous electrical path to prevent electrical shock hazards.

Adjustable Bolts: These bolts have a mechanism for adjusting the tilt angle of solar panels to optimize their orientation for maximum sunlight exposure.

Stainless Steel Bolts: Stainless steel bolts are often preferred in PV assembly due to their corrosion resistance, which is important for outdoor installations exposed to the elements.

When selecting bolts for a PV assembly, it’s important to consider factors such as the material of the mounting structure, environmental conditions, load requirements, and the specific design of the solar panel installation.  It is recommended to consult with a professional or refer to the manufacturer’s guidelines to choose the right bolts for your solar panel system.