The system is composed of an earthing clamp paired with a lock-out padlock, both using the same key that remains in the clamp when in use. This imposes an order of installation of the equipment during lock-out procedure as well as an order of removal during power-up. It becomes impossible to power-up while the clamp is in place. This situation can occur when there are multiple or distant systems. The padlock paired to the clamp is a complement to the usual padlock installed by the lock out master.
Warning, the solution is a control method that mechanically blocks the power-up as long as the earthing lead is not removed. It must not be confused with the imperative rules of lock out made to protect the operators during lock-out work per the codes NF C 18-510 or the code EN 50110-1