What must be ensured when bonding metallic piping systems?

When bonding metallic piping systems, it is crucial to ensure electrical continuity without interruptions. This means that all metallic components of the piping system must be electrically interconnected to minimize resistance and allow fault current to flow effectively in the event of a fault. This bonding provides a low-resistance path that helps to facilitate proper grounding, enhancing the safety of the electrical system by preventing electric shock hazards and equipment damage.

The other options, while they may seem relevant, do not capture the essential requirement for bonding. For instance, welding all joints may not be necessary or practical in every situation, as there are various methods for bonding that can achieve electrical continuity. Similarly, while painted pipes can affect conductivity, the most critical factor is ensuring that all connections provide continuous electrical paths, regardless of the paint. Insulating connections counteracts the purpose of bonding since insulation would prevent electrical continuity, which is key for effective fault current management. Thus, focusing on uninterrupted electrical continuity is the heart of proper bonding practice.