For equipment rated at 800A or more, what requirement is specified for entrances to the working space?

For equipment rated at 800 amperes or more, the requirement that the entrance to the working space shall open at least 90 degrees in the direction of egress is essential for maintaining safe and efficient access. This specification ensures that personnel can easily and safely enter or exit the working space without obstruction, which is crucial in emergency situations or when access is needed for routine maintenance or troubleshooting.

The reasoning behind this requirement is to enhance safety and minimize the risk of injury. A door that opens wide enough allows for quick access, especially when handling tools or equipment, or when personnel need to retreat quickly in case of an incident. It helps in avoiding any potential hindrance that might be caused by a smaller opening or a door that does not swing wide enough.

In regard to the other options, while safety is always a priority, they do not directly address the specific requirements for the accessibility of the working space entrance as stipulated for electrical installations of this size. Consideration of fire resistance, distance from equipment, and lock mechanisms, while important in other contexts, do not take precedence over ensuring that the entrance allows for adequate and safe egress in emergency situations.