Portable Appliance Testing (PAT)
From 99p per item
All electrical systems and equipment should be maintained and inspected regularly under the Health & Safety at Work Act 1974, The Electricity at Work Regulations 1990, The Management of Health & Safety at Work Regulations 1999 and The Provisions and Use Of Work Equipment Regulations 1998 (PUWER).
The guidance for frequencies depends on the environment and usage but as a guide states:
Handheld equipment : 6 Monthly
Portable/movable equipment: 12 Monthly
Fixed equipment: 24 Monthly