Commercial Electrician in IP33

Part P does not apply to commercial premises. The law that does is the Electricity at Work Regulations 1989, and it puts the duty on the employer or occupier as duty holder. Regulation 4(2) requires the system to be maintained so as to prevent danger, so far as is reasonably practicable. Regulation 14 is the reason a competent electrician isolates rather than taking a quick look at a live board.

The five-year testing interval everybody quotes is not law. It comes from Table 3.2 of IET Guidance Note 3, which lists recommended initial inspection frequencies. HSE's own position is that installations should be tested often enough that there is little chance of deterioration leading to danger. In practice your insurer, your lease or your last report sets the date.

The work itself differs from domestic in the supply as much as the paperwork. Three-phase 400 V distribution boards, sub-mains, SWA on tray and basket, motor and refrigeration circuits, LED and high bay lighting. Shutdowns are normally booked outside trading hours. Commercial work here means three-phase distribution, motor circuits, fire alarm servicing, emergency lighting, in-service inspection and testing, and maintenance contracts on the schedule your insurer or landlord asks for.