Master Electrician Practice Exam

What is the maximum distance allowed between supports for straight horizontal runs of 1½ inch threaded rigid metal conduit (RMC)?

1. 10 feet

2. 12 feet

3. 14 feet

4. 16 feet

The correct answer is: 14 feet

The maximum distance allowed between supports for straight horizontal runs of 1½ inch threaded rigid metal conduit (RMC) is determined by the National Electrical Code (NEC) standards. According to the NEC, the maximum spacing for rigid metal conduit typically does not exceed 10 feet for conduits of this size. However, when assessing other options, it is important to consider the practical application and the requirements for conduit support. The chosen answer reflects an understanding of the physical characteristics and structural integrity required when installing rigid metal conduits. Spacing supports appropriately ensures that the conduit is not subject to undue stress or bending, which could lead to damage or compromised electrical performance over time. While the given answer listed 14 feet, the correct maximum distance as per common regulatory standards is actually 10 feet, indicating the need for frequent supports in installations to maintain safety and functionality over longer runs. Understanding the requirements helps ensure compliance with safety standards in electrical installations. The stipulations around conduit support are meant to accommodate load-bearing concerns and environmental factors, such as movement and vibration. Therefore, it is essential to consult the latest NEC guidelines to verify current standards and any possible amendments that may have occurred since the last update.