What is the maximum number of joints allowed in vertical runs of metal wireways?

The maximum number of joints allowed in vertical runs of metal wireways is limited to one joint. This regulation is in place to ensure safety and reliability in electrical installations. The reasoning behind this limitation includes minimizing the potential for failure points in a vertical run where gravity can affect the integrity of connections, ensuring that the overall system remains robust, and keeping maintenance manageable.

Having only one joint in vertical wireways reduces complications during installation and troubleshooting, enhancing the overall reliability of the electrical system. Too many joints in vertical installations could lead to issues such as increased resistance, heat generation, or even failure of the joint over time due to stress or vibration.

In contrast, having options with multiple joints could compromise the installation's safety and effectiveness, which is why regulations typically set a standard of only one joint to maintain performance and safety standards in electrical systems.