Which fastening device is deemed unacceptable for securing the dead front cover?

The fastening device considered unacceptable for securing the dead front cover is wood screws. This is primarily due to safety concerns and the need for reliable and secure electrical installations. Wood screws are not designed for use in metal or electrical enclosures, as they may not create a secure and lasting connection. Additionally, wood screws can break or strip easily under stress, which can lead to unsafe conditions such as exposure to live electrical components.

In contrast, other options like metal spikes and self-tapping screws are designed to provide a more secure fastening suitable for metal components and can properly anchor into electrical panels. Plastic anchors can also be used in certain circumstances, provided that they conform to safety regulations and are installed appropriately. Hence, the use of wood screws is not recommended in this context due to their inadequate performance and reliability compared to the other mentioned options.