A health and safety briefing provided by the IET.
Permits to work are used to let employees know that essential precautions have been taken and, where necessary, physical safeguards are in place - e.g. circuits open and contactors or switches securely locked open.
A permit either suspends and temporarily replaces, or augments, existing systems of work.
The process of requesting, raising and issuing permits is a procedure within the procedure of a safe system of work.
Self-permitting is inherently less safe (even dangerous) and is not recommended despite its widespread use.