2.1 Health, Safety and Continuity Law

2.1 Health, Safety and Continuity Law

Quick Answer: Design, installation, and commissioning of solar photovoltaic (PV) systems and electrical energy storage systems (EESS) sit under three statutes you must be able to separate. The Health and Safety at Work etc. Act 1974 (HSWA) protects people. The Electricity at Work Regulations 1989 (EAWR) prevent danger from electrical systems and tightly control live work. The Electricity Safety, Quality and Continuity Regulations 2002 (ESQCR) control parallel connection to the public network. MCS MIS 3002 cites ESQCR Regulation 22(2)(c) and requires EREC G98 at or below 16 A per phase, G99 above 16 A per phase, and G100 where export is limited. Add the battery or hybrid AC rating to the PV inverter rating before you decide which Engineering Recommendation applies.

This independent OpenExamPrep chapter is a study resource for City & Guilds 2922-34 (Level 3 Award in the Installation and Maintenance of Small Solar Photovoltaic (PV) Systems), Qualification Handbook v1.3 (August 2025). It is not an official City & Guilds, IET, or MCS publication. Learning Outcome 1 is only 7 percent of the knowledge test (2 questions), but the handbook still teaches the statutory set in full, and it includes EESS documentation even on this PV award. Treat the two exam items as a reason to be precise, not a reason to skim.

The three statutes answer different questions on the same job. HSWA asks who must look after people on a roof, in a loft, and in a customer's garden. EAWR asks how you stop electrical systems injuring those people when DC remains live in daylight. ESQCR asks how you connect generation in parallel with a distributor's network without creating danger or interference for other customers. Mixing those questions is how candidates write “G98” when the real issue is a missing RAMS, or “HSWA” when the DNO should have had a G99 application.

Health and Safety at Work etc. Act 1974

HSWA is the umbrella health-and-safety statute. Section 2 sets general duties of employers to their employees. Section 3 sets general duties of employers and of self-employed people to persons other than their employees — the householder, other trades, neighbours, and members of the public who walk under a ladder or a roof edge. Section 7 sets general duties of employees at work: take reasonable care of yourself and others, and cooperate with the duty holder. A 2922-34 candidate who only ever works as a self-employed installer is not outside the Act. Self-employed people still owe section 3 duties, and anyone they bring onto site as an employee or labour-only worker brings section 2 back into play.

On solar PV and EESS work those duties become a risk assessment and method statement (RAMS) culture, not a folder that lives in the van unread. Typical residual risks are work at height on pitched roofs, fragile coverings, manual handling of modules and battery enclosures, and live DC that cannot be switched off while the array is illuminated. The RAMS should name the access method, edge protection or fall-arrest choice, weather hold-points, exclusion zones below the eaves, and the electrical isolation sequence. Writing “care will be taken” does not discharge HSWA. Naming who isolates, who proves dead, who holds the keys, and who stops the job if irradiance or wind changes does.

HSWA also explains why competence is not a slogan. The people who design the array layout, who torque roof fixings, who terminate DC connectors, and who commission a hybrid inverter all affect employees and other persons. If you send an inexperienced mate onto a live DC roof with no briefing, the failure is a people-duty failure under HSWA even before anyone discusses milliamps or G99.

In practice: A two-person domestic crew arrives at a 30-degree tiled roof. The employer (or self-employed lead) has duties to the mate and to the household. The RAMS covers scaffold or powered access, module handling, and the fact that string cables remain live in daylight. The mate has an employee duty to use the kit provided and to speak up if the isolation plan is missing. None of that is “electrical regulations theatre.” It is HSWA applied to a PV roof.

Electricity at Work Regulations 1989

EAWR sit under the HSWA framework and make electrical danger specific. Regulation 4 requires systems to be constructed, maintained, and worked on so as to prevent danger so far as is reasonably practicable, and requires protective equipment to be suitable. Regulation 12 requires means for cutting off the supply and for isolation. Regulation 13 requires precautions when work is done on equipment that has been made dead. Regulation 16 requires people to be competent to prevent danger and injury. Those regulations are why a PV job is not finished when the inverter display lights up.

Regulation 14 is the live-working gate, and it is conjunctive — all three limbs must be true. No person shall work on or so near a live conductor that danger may arise unless: (a) it is unreasonable in all the circumstances for it to be dead; (b) it is reasonable in all the circumstances to work on or near it while it is live; and (c) suitable precautions (including protective equipment where needed) are taken to prevent injury. “I was in a hurry” and “the customer wanted it on before sunset” are not Regulation 14 justifications.

PV arrays create a distinctive EAWR problem: the generator cannot be switched off in daylight. Covering modules, waiting for night, or opening a DC isolator after a controlled shutdown can reduce risk, but an illuminated array, damaged cable, or connector still presents voltage. You therefore implement EAWR with control measures rather than pretending the array is a conventional final circuit you can isolate at a consumer unit and forget.

Those control measures are exam-useful because they are also good practice:

• Follow a shutdown and isolation sequence (inverter shutdown, AC isolation, DC isolation, prove dead where you can, lock-off and label).
• Use DC-rated isolators, connectors, crimps, and test equipment. An AC device that cannot break DC current is not “nearly good enough.”
• Do not load-break on connectors. Unmating a DC connector under load is an arc hazard. If connectors are used as a means of isolation, an additional load-breaking device is required so that you are not asking a plug to do a switch-disconnector's job.
• Treat residual live parts as live. Voltage can exist on either side of a connector. Combiner boxes can remain energised from other strings.

EAWR is the statute behind those habits. The later chapters on isolation and testing show the sequence in more detail. This section's job is to make you able to say why the sequence exists: to prevent danger from an electrical system that stays live whenever there is light.

Electricity Safety, Quality and Continuity Regulations 2002

ESQCR 2002 are about the public network, not about your ladder. Regulation 22 (parallel operation, extent England, Wales, and Scotland) says that no person shall install or operate a source of energy which may be connected in parallel with a distributor's network unless specified conditions are met, including equipment to prevent danger or interference so far as reasonably practicable. Regulation 22(2) then relaxes some of the personnel and distributor-agreement conditions for small sources that, among other things, do not produce an electrical output exceeding 16 amperes per phase at low voltage, disconnect when the distributor disconnects, and — at Regulation 22(2)(c) — ensure the distributor is advised of the intention to use the source in parallel before or at commissioning.

MIS 3002 cites that Regulation 22(2)(c) hook and requires the installer-scheme contractor to follow the technical requirements and procedures in:

• EREC G98 for installations up to and including 16 A per phase
• EREC G99 for installations exceeding 16 A per phase
• EREC G100 where export of power is to be limited

On a nominal 230 V single-phase supply, 16 A is about 3.68 kW (16 × 230 = 3,680 W). That threshold is aggregated AC output of all generators on the connection, not “the PV inverter if you squint and ignore the battery.” MIS 3002 states that a 3 kW PV system and a 3 kW electrical energy storage system in parallel on the same single-phase supply give a combined maximum theoretical output greater than 16 A, so G99 applies. G98 is typically a connect-and-notify route for qualifying fully type-tested micro-generation. G99 is an apply-before-you-connect route. G100 is the export-limitation recommendation used when the DNO requires a cap.

A 27 August 2026 amendment substituted ESQCR Regulation 22(1)(c) to distinguish a low-voltage consumer's installation that complies with British Standard Requirements from a plug-in microgenerator that complies with the Plug-in Solar Device Interim Product Specification. For 2922-34 rooftop and hybrid work you are still installing a parallel source in a consumer's installation. Do not treat a string-inverter array as a plug-in windowsill toy, and do not skip G98/G99/G100 because a plug-in product class now appears in the statute.

Worked scenario: 3.6 kW PV plus 5 kW hybrid on single-phase

A household wants 3.6 kW of PV and a 5 kW hybrid inverter with battery on a single-phase cut-out. The PV inverter nameplate (3.6 kW) is just under 3.68 kW, so a candidate who only reads “solar” writes G98 and books the job for next week.

That reading is wrong for ESQCR/MCS aggregation. The hybrid/battery AC output of 5 kW is about 21.7 A at 230 V. Even if the PV path alone would have fitted G98, the site’s combined generation capability is well above 16 A per phase. G99 applies. If the DNO then requires an export cap, G100 sits on top of that connection process; G100 does not replace G99. The installer still needs EAWR isolation design for a dual-source installation and HSWA RAMS for roof and battery handling. Passing the knowledge test means you can hold all three statutes in one domestic hallway without collapsing them into “the solar form.”

If the same house later adds a second AC-coupled battery, you re-aggregate. G98 is not a grandfathered badge you keep after the site grows.

Official sources

• Health and Safety at Work etc. Act 1974 — sections 2, 3, and 7 duties.
• Electricity at Work Regulations 1989 — especially regulations 4, 12, 13, 14, and 16.
• ESQCR 2002 Regulation 22 — parallel operation, 16 A exemption conditions, and Regulation 22(2)(c) notification.
• MCS MIS 3002 Issue 6.0 (18 March 2026) — installer-scheme citation of Regulation 22(2)(c) and G98/G99/G100, including aggregated PV plus storage AC output.

Confirm the current G98/G99/G100 issue on the Energy Networks Association pages when you notify a live job. This study resource explains the statutory map for 2922-34; it does not replace the Engineering Recommendation text you use on site.