Periodic inspection and testing are necessary because all electrical installations deteriorate due to many factors such as ageing, excessive electrical loading, corrosion, and general wear and tear.
A periodic test and inspection may be less onerous than an initial one. Completing unnecessary periodic testing can be dangerous, disruptive and costly. This is often misunderstood by companies wishing to achieve legal compliance.
It is good practice to work to a periodic electrical testing plan, and this ensures compliance with the Regulations without incurring excessive disruption and costs to the user.