1.Conductivity of Armor Layer

2.The provisions of NEC 250.118
According to NEC 250.118, the armor layer of some MC cables is recognized as an effective grounding path, provided that the armor is specially designed and can provide a continuous low impedance path. Generally speaking, MC cables with continuous metal sheaths or additional grounding conductors are more recognized by regulations.
3.Mechanical integrity and continuity

1.Standard MC cable: If the armor layer complies with NEC 250.118 regulations and is properly connected, it can be used as a grounding path.
2.Armored MC Cable: For example, 14 3 armored cables generally use independent grounding conductors instead of relying on armor layers.
3.PVC coated MC cable: such as 12 2 PVC coated MC cable, its external PVC protective layer may affect the grounding effect of the armor layer, so an internal grounding conductor is usually required.

1.Prioritize the use of independent grounding conductors in critical application scenarios, and it is recommended to choose MC cables with dedicated grounding conductors instead of relying solely on armor layers for grounding.
2.Strictly follow electrical specifications. Installation personnel should consult NEC specifications and local regulations before construction to ensure that the installation complies with relevant standards.
3.When correctly installing connectors to connect MC cables, it is necessary to use connectors that comply with NEC certification and ensure a secure connection to prevent the armor layer from loosening or breaking.