Code Change Summary: Revised code language on main bonding jumper material.
In the 2020 NEC®, main bonding jumpers are now permitted to be made of aluminum and copper-clad aluminum. Technically, the materials weren’t prohibited before, but they weren’t specifically mentioned either, except in Table 250.102(C)(1) which specifies the minimum size main bonding jumper permitted based on the material type.
In the 2020 NEC®, aluminum and copper-clad aluminum were added to 250.28(A) to align with the materials shown in Table 250.102(C)(1).
Below is a preview of the NEC®. See the actual NEC® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2020 NEC® edition of NFPA 70.
2017 Code Language:
250.28(A) Material. Main bonding jumpers and system bonding jumpers shall be of copper or other corrosion-resistant material. A main bonding jumper and a system bonding jumper shall be a wire, bus, screw, or similar suitable conductor.
2020 Code Language:
250.28(A) Material. Main bonding jumpers and system bonding jumpers shall be of copper, aluminum, copper-clad aluminum, or other corrosion-resistant material. A main bonding jumper and a system bonding jumper shall be a wire, bus, screw, or similar suitable conductor.
Refer to the image of NEC Table 250.102(C)(1):
What is the minimum size aluminum main bonding jumper permitted if the ungrounded conductors are 500 kcmil aluminum?
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