Yes, according to the NEC (National Electrical Code), you generally DO need to bond the metallic conduit (even if non-ferrous like aluminum) that contains the grounding electrode conductor (GEC) to the GEC itself. Here's why and the relevant code sections

Reasoning:
Parallel Path

The metal conduit, even if non-ferrous, can create a parallel path for ground fault current. This is undesirable because: It might have higher impedance than the intended GEC path, hindering fault clearing. It could lead to current flowing on the conduit, potentially causing touch voltage issues (making the conduit energized during a fault).

Fault Current Capacity

By bonding the conduit to the GEC, you ensure that the conduit and the GEC are at the same potential, thus minimizing the chance of voltage differences during a fault. This increases the overall fault current-carrying capacity of the grounding system.

Safety

Equalizing the potential between the GEC and the conduit reduces the risk of shock hazards should someone come into contact with the conduit during a ground fault.

Relevant NEC Sections (Examples)



NEC 250.64(E) Securing and Protection Against Physical Damage

While this section primarily deals with securing and protecting the GEC, it implicitly requires bonding when the GEC is run in metallic raceway. It requires the raceway to be electrically continuous from the point of attachment to cabinets, equipment enclosures, or grounding electrodes.

NEC 250.92(B) Methods of Bonding

This section refers to the acceptable methods for bonding metal raceways and enclosures to ensure electrical continuity and fault current path integrity. Methods like bonding jumpers and approved fittings are outlined.

How to Bond



Bonding Jumpers

Use listed bonding jumpers (wires with terminals) to connect the conduit to the GEC. These are typically sized according to NEC table 250.102(C)(1) based on the size of the ungrounded service conductors.

Approved Fittings

Use listed fittings designed for bonding conduit. These fittings provide a low-impedance connection between the conduit and the enclosure it terminates into, which should itself be bonded.

Direct Connection

In some cases, the fitting itself is designed to bond the conduit to the enclosure (e.g., a grounding bushing with a lug for a bonding jumper).

Important Considerations



Size of Bonding Jumper

The size of the bonding jumper connecting the conduit to the GEC is based on the size of the service entrance conductors, not the grounding electrode conductor. Refer to NEC Table 250.102(C)(1) or similar.

Location of Bonding

Bond the conduit at both ends - where it connects to the service equipment and where it connects to the grounding electrode system. This ensures a low-impedance path throughout the entire length of the conduit.

Material Compatibility

Ensure that the bonding jumpers and connectors are compatible with the materials being joined (e.g., use aluminum connectors for aluminum conduit).

Local Amendments

Always check for any local amendments to the NEC in your jurisdiction. These amendments can sometimes modify or add to the requirements.

In summary, for metallic conduit containing the grounding electrode conductor, bonding to the GEC is generally required to maintain electrical safety and ensure a proper fault current path. Always consult the NEC and local codes for specific requirements in your area. Flag for review