The general protection box or CGP is a box of insulating material that houses inside the protection elements of the general power lines of an electrical installation. The CGP connects the electricity consumption points or customers to the distribution company's network, normally at low voltage.

In addition to physically making the connection, it delimits the ownership and responsibility between the distribution company and the customer, and contains fuses to prevent breakdowns in their internal network from spreading to the distribution company's network and, therefore, affecting other customers.

They are preferably installed outside buildings and in the area closest to the distribution network, in places with free and permanent access. When the façade does not border the public road, the general protection box will be located on the boundary between public and private properties.

When the connection (distribution company network) is aerial, it can be installed in surface mounting, the aerial installation will be done at an altitude of between 3 and 4 m from the ground. When the connection is underground, it will be installed inside a wall compartment, which will be closed with a preferably metal door. The bottom of the door will be a minimum of 3 dm from the floor.

The boxes to be used will be according to the corresponding UNE standards and within them fuses will be installed in all the phase conductors, calibrated according to the short-circuit current expected at the point of consumption, the neutral will be formed by a removable connection located to the left of the phases and will also have a terminal for connection to ground if applicable.

General Protection Boxes are recommended to be Class II (double insulation or reinforced insulation).