Opening the AC breaker does not establish a safe DC work boundary. Illuminated PV modules can maintain voltage upstream of a disconnect, and internal stored energy needs the specified waiting and verification process. Never improvise a short-circuit discharge.
This reference material was written and revised with AI. It has not been verified or approved by a professional. Review by a suitably qualified professional and required site approval are necessary before field use.
Stop before proceeding
Hold connection and access for unknown sources, boundary or voltage state, reversed polarity, unverified connector pairing or damaged cables. Restrict access for ground faults, arcing, charring or water ingress.
1. Legal and technical scope
Construction installation is assessed under 1926.403/.416/.417; general-industry electrical work uses applicable 1910.333 practices. Adopted electrical codes, utility requirements, NFPA 70/70E guidance and manufacturer instructions have different roles and require site-specific edition/applicability checks. English-language manufacturer pages do not establish US product listing or utility acceptance.
Confirm whether federal OSHA or an OSHA-approved State Plan covers this employer and worksite; state requirements and public-sector coverage can differ. Apply the task-specific provisions and limitations identified above.
| Basis | Application |
|---|---|
| OSHA 29 CFR 1926.403 | Construction electrical installation suitability and identified/listed equipment use. |
| OSHA 29 CFR 1926.416 | Construction electrical hazard protection. |
| OSHA 29 CFR 1926.417 | Construction circuit isolation controls. |
| OSHA 29 CFR 1910.333 | Applicable general-industry deenergization, stored energy and voltage verification. |
| SMA Sunny Boy safety instructions | Model-specific PV voltage, no loaded disconnection and fault-state precautions; not a universal switching sequence or proof of US listing. |
| Stäubli MA294 | Page 2 safety: deenergization, no loaded disconnection, no contaminated mating and no cross-manufacturer mating for the stated products. Actual connector assembly instructions govern. |
| OSHA State Plans | Official overview of federal and State Plan jurisdiction and differing public-sector coverage, checked 2026-10-12. Individual state rules require a site-specific check. |
2. Scope and required inputs
Included scope
Verify inverter mounting and environment, establish AC/DC/stored-energy boundaries, prepare compatible connectors, complete permitted deenergized DC wiring, perform specified checks and transfer operating restrictions.
Separate assessment
Exposed energized wiring, disconnecting loaded connectors, improvised short-circuit discharge, internal inverter repair and switching outside model instructions are excluded. Roof access and lifting require their separate plans.
| Input | Evidence needed |
|---|---|
| Map all sources | AC DC and storage; Isolation and access; Wait and test instruction; String and drawing IDs. |
| Mount and isolate | Mount and fastening; Source inventory; Tester and work-point result; Stored-energy record. |
| Wire and support | Terminal voltage state; Tightening record; Ground connection; Bend seal and strain. |
| Handoff operation | As-built mapping; Polarity ground and sealing; Test and startup record; Authority and receiver. |
No site measurements, equipment manuals for the actual installation, inspection records or signed technical approvals were supplied. Confirm the applicable requirements and actual product instructions before use; record each criterion with its units, source and equipment or work-area ID.
3. Eight-stage JSA
| Job stage | Hazards and effects | Failure factors | Technical and procedural controls | Site verification | P | S | R | A |
|---|---|---|---|---|---|---|---|---|
| 1. Map all sources | 1. DC shock2. Arc exposure3. Stored-charge release4. Wrong string connected | 1. AC-only isolation2. No-load mistaken for dead3. Wait omitted4. Mapping mismatch | 1. Identify every source2. Define DC boundaries3. Set model verification4. Identify each string | 1. AC DC and storage2. Isolation and access3. Wait and test instruction4. String and drawing IDs | ||||
| 2. Prepare mounting | 1. Dropped inverter2. Overheating3. Cable damage4. Live contact | 1. Bracket unverified2. Clearance missing3. Sharp route4. No terminal barrier | 1. Verify mount and lifting2. Match installation space3. Protect cable route4. Guard remaining live parts | 1. Weight and brackets2. Airflow and environment3. Cable supports4. Live-side boundary | ||||
| 3. Mount and isolate | 1. Inverter falls2. AC backfeed3. PV voltage contact4. Capacitor discharge | 1. Wrong fasteners2. Supply omitted3. Sunlight ignored4. Time alone trusted | 1. Verify structural support2. Control AC and DC sources3. Lock and test work boundary4. Follow wait and verification | 1. Mount and fastening2. Source inventory3. Tester and work-point result4. Stored-energy record | ||||
| 4. Prepare connectors | 1. Reverse polarity2. DC arc3. Hot contact4. Insulation failure | 1. Unverified pair2. Wrong crimp tool3. Wrong strip length4. Damaged strands | 1. Match permitted pair2. Use specified tooling3. Follow assembly dimensions4. Inspect contacts and seals | 1. Both connector part IDs2. Tool and die match3. Polarity and crimp4. Damage and cleanliness | ||||
| 5. Wire and support | 1. Live terminal contact2. Hot termination3. Ground path lost4. Cable tension | 1. State not rechecked2. Torque guessed3. Ground omitted4. Entry unsupported | 1. Recheck work-point state2. Use specified tightening3. Connect protective ground4. Support and seal entries | 1. Terminal voltage state2. Tightening record3. Ground connection4. Bend seal and strain | ||||
| 6. Test and restore | 1. Reversed string damage2. Test overvoltage3. Ground fault4. Live rework | 1. Mapping incorrect2. Electronics connected3. Defect ignored4. Re-isolation omitted | 1. Verify design and polarity2. Use approved test setup3. Resolve faults before start4. Re-isolate before rework | 1. String range and polarity2. Test settings and boundary3. Alarm and stop results4. Restoration release | ||||
| 7. Hold abnormalities | 1. DC arc2. Ground exposure3. Repeated bad connection4. Fault-state incident | 1. Loaded disconnect2. Water ignored3. Pair issue unresolved4. Unsafe switch action | 1. Stop connection access2. Follow model fault plan3. Quarantine bad components4. Use qualified recovery | 1. Alarm and fault state2. Safe access boundary3. Pair and change history4. Retest restrictions | ||||
| 8. Handoff operation | 1. Wrong circuit starts2. Grounding incomplete3. Defect operated4. Traceability lost | 1. Final map unchecked2. Inspection missing3. Startup-only release4. Limit not transferred | 1. Match final string map2. Check grounding and seals3. Record operating scope4. Transfer unresolved limits | 1. As-built mapping2. Polarity ground and sealing3. Test and startup record4. Authority and receiver |
P = likelihood; S = severity; R = risk under the site method; A = the site-defined acceptance/authorization decision. Complete only after actual assessment. Blank cells and checklist prompts are not completed inspections.
4. Fictional scenario and failure mechanisms
Retained AI-generated educational illustration from the source edition; not a real incident photograph, approved installation drawing or evidence of equipment suitability.
The scenario and record comparisons are fictional teaching examples, not records of real incidents, measurements, inspections, signatures or approvals.
| Item | Fictional scenario |
|---|---|
| Initial | The inverter AC breaker is open before wiring. |
| Change | The installer assumes every DC terminal is also deenergized. |
| Failure | Array output and internal stored energy are not checked at the work boundary. |
| Outcome | Shock or a connector arc can occur despite the AC-off indication. |
| Barrier | Hold connection work until a qualified person establishes the permitted boundary and verifies the model-specific isolation and connector conditions. |
Why the controls matter
Opening the AC breaker does not establish a safe DC work boundary. Illuminated PV modules can maintain voltage upstream of a disconnect, and internal stored energy needs the specified waiting and verification process. Never improvise a short-circuit discharge.
Zero current is not zero voltage. A clamp-current result cannot authorize contact with an exposed terminal. Identify the exact points that can be worked on and continue to guard the remaining energized array-side wiring.
Matching connector shapes or a compatibility claim do not prove a permitted pair. The cited Stäubli instruction prohibits mating its stated products with another manufacturer. Check the actual pair, cable, contacts, seals, tooling, polarity and test boundary; do not apply insulation-test voltage through unprotected electronics.
Decision sequence
| Step | Decision |
|---|---|
| Known | The installer assumes every DC terminal is also deenergized. |
| Unknown | Actual condition, extent of damage and suitability of terminal voltage state, tightening record remain to be established. |
| Hold | Array output and internal stored energy are not checked at the work boundary. |
| Evidence | Link terminal voltage state, tightening record, ground connection, bend seal and strain, alarm and fault state, safe access boundary to the affected equipment or work area. |
| Next | Hold connection work until a qualified person establishes the permitted boundary and verifies the model-specific isolation and connector conditions. |
5. Conditional decisions and common errors
| Condition | Action | Evidence | Proceed when |
|---|---|---|---|
| AC off only | Hold DC access | All sources and boundary test | Work-point state verified |
| Connector pair unknown | Do not mate | Both manufacturer/type IDs | Permitted pair confirmed |
| Test proposed | Protect affected electronics | Approved test boundary/settings | Test setup verified |
| Fault or ground alarm | Restrict access | Model fault procedure | Qualified recovery released |
Similar appearance, different evidence
The scenario and record comparisons are fictional teaching examples, not records of real incidents, measurements, inspections, signatures or approvals.
| Comparison | Supported decision | Insufficient basis |
|---|---|---|
| Condition | All sources and boundary test | AC off only has not been resolved. |
| Evidence | Approved test boundary/settings | A photograph or a completed-looking task without the relevant inspection record. |
| Release | Qualified recovery released | Completion of one step does not release the excluded tasks in section 2. |
6. Roles and responsibilities
| Role | Responsibility |
|---|---|
| Work supervisor | Assign the task boundary, stop authority, interfaces and emergency communication for solar inverter installation and dc wiring. |
| Technical lead | Confirm AC DC and storage; Isolation and access; Wait and test instruction; String and drawing IDs. Resolve design and manufacturer limits before work. |
| Authorized crew | Apply Mount and fastening; Source inventory; Tester and work-point result; Stored-energy record. Stop when the working arrangement changes. |
| Inspector / receiving lead | Review Terminal voltage state; Tightening record; Ground connection; Bend seal and strain. Transfer As-built mapping; Polarity ground and sealing; Test and startup record; Authority and receiver. |
Role labels allocate responsibilities; they do not confer a legal qualification. Verify the competence, training and authority required for the actual task.
Record and handoff perspective
| Stage | Record controls | Verification |
|---|---|---|
| Map all sources | 1. Record ac dc and storage2. Record isolation and access3. Record wait and test instruction | 1. Isolation and access2. Wait and test instruction3. String and drawing IDs |
| Mount and isolate | 1. Record mount and fastening2. Record source inventory3. Record tester and work-point result | 1. Source inventory2. Tester and work-point result3. Stored-energy record |
| Prepare connectors | 1. Record both connector part ids2. Record tool and die match3. Record polarity and crimp | 1. Tool and die match2. Polarity and crimp3. Damage and cleanliness |
| Wire and support | 1. Record terminal voltage state2. Record tightening record3. Record ground connection | 1. Tightening record2. Ground connection3. Bend seal and strain |
| Hold abnormalities | 1. Record alarm and fault state2. Record safe access boundary3. Record pair and change history | 1. Safe access boundary2. Pair and change history3. Retest restrictions |
| Handoff operation | 1. Record as-built mapping2. Record polarity ground and sealing3. Record test and startup record | 1. Polarity ground and sealing2. Test and startup record3. Authority and receiver |
7. Hold points and record comparison
| Hold point | Evidence before release | Actual record |
|---|---|---|
| HP-0 Start | Verify inverter mounting and environment, establish AC/DC/stored-energy boundaries, prepare compatible connectors, complete permitted deenergized DC wiring, perform specified checks and transfer operating restrictions. | |
| HP-1 Mount and isolate | Mount and fastening; Source inventory; Tester and work-point result; Stored-energy record | |
| HP-2 Prepare connectors | Both connector part IDs; Tool and die match; Polarity and crimp; Damage and cleanliness | |
| HP-3 Test and restore | String range and polarity; Test settings and boundary; Alarm and stop results; Restoration release | |
| HP-4 Handoff operation | As-built mapping; Polarity ground and sealing; Test and startup record; Authority and receiver |
These are internal hold points, not issued permits. Recheck affected points after a change, fault or shift handoff; link the actual approval record.
Record comparison
The scenario and record comparisons are fictional teaching examples, not records of real incidents, measurements, inspections, signatures or approvals.
The boxes are static record prompts, not interactive or saved approvals. A tick does not establish suitability or permission to restart. Record the evidence, person, time and unresolved issues; retain the change history.
| Record | Insufficient | Record checklist |
|---|---|---|
| Map all sources | "Checked" without target, criteria or result | □ AC DC and storage□ Isolation and access□ Wait and test instruction□ String and drawing IDs |
| Mount and isolate | "Checked" without target, criteria or result | □ Mount and fastening□ Source inventory□ Tester and work-point result□ Stored-energy record |
| Wire and support | "Checked" without target, criteria or result | □ Terminal voltage state□ Tightening record□ Ground connection□ Bend seal and strain |
| Handoff operation | "Checked" without target, criteria or result | □ As-built mapping□ Polarity ground and sealing□ Test and startup record□ Authority and receiver |
8. Site checklist and emergency response
| Check | Result | Person / action |
|---|---|---|
| □ Map all sources: AC DC and storage | ||
| □ Prepare mounting: Weight and brackets | ||
| □ Mount and isolate: Mount and fastening | ||
| □ Prepare connectors: Both connector part IDs | ||
| □ Wire and support: Terminal voltage state | ||
| □ Test and restore: String range and polarity | ||
| □ Hold abnormalities: Alarm and fault state | ||
| □ Handoff operation: As-built mapping | ||
| □ Emergency access and handoff restrictions |
Stop work
Hold connection and access for unknown sources, boundary or voltage state, reversed polarity, unverified connector pairing or damaged cables. Restrict access for ground faults, arcing, charring or water ingress.
Emergency response
Restrict the area and notify qualified electrical personnel and 911/site response as needed. Do not open a faulted inverter or pull connectors. Use only external switching permitted by the actual fault procedure; relay that array-side voltage may remain.
9. Sources and review limits
Public-source review: 2026-10-12. Official regulation pages and specific technical references are distinguished below; no agency or manufacturer has approved this content.
| Source | Reviewed scope and limitation |
|---|---|
| OSHA 29 CFR 1926.403 | Construction electrical installation suitability and identified/listed equipment use. |
| OSHA 29 CFR 1926.416 | Construction electrical hazard protection. |
| OSHA 29 CFR 1926.417 | Construction circuit isolation controls. |
| OSHA 29 CFR 1910.333 | Applicable general-industry deenergization, stored energy and voltage verification. |
| SMA Sunny Boy safety instructions | Model-specific PV voltage, no loaded disconnection and fault-state precautions; not a universal switching sequence or proof of US listing. |
| Stäubli MA294 | Page 2 safety: deenergization, no loaded disconnection, no contaminated mating and no cross-manufacturer mating for the stated products. Actual connector assembly instructions govern. |
| OSHA State Plans | Official overview of federal and State Plan jurisdiction and differing public-sector coverage, checked 2026-10-12. Individual state rules require a site-specific check. |
No site measurements, equipment manuals for the actual installation, inspection records or signed technical approvals were supplied. Confirm the applicable requirements and actual product instructions before use; record each criterion with its units, source and equipment or work-area ID.
10. PDF guidance and FAQ
PDF A covers basic task controls; B focuses on technical failures; C covers supervision, records and handover. The article has eight stages with four items per main cell; each PDF has six key stages with three items per main cell. P/S/R/A, measurements, confirmations and signatures remain blank for actual site assessment.
Content group
jsa-inverter-dcwiring
Does AC shutdown permit DC wiring?
No. Identify array, storage and internal energy and verify the exact work boundary.
Does zero current mean no voltage?
No. Current and voltage are different conditions; use the specified voltage verification and connection procedure.
Can look-alike PV connectors be mixed?
Use only the permitted actual combination; the cited Stäubli instructions prohibit its products being mated with other manufacturers.
Does successful startup close the job?
No. Transfer polarity, grounding, sealing, test results, alarms, final string mapping and unresolved restrictions.
Has a professional approved this JSA?
This reference material was written and revised with AI. It has not been verified or approved by a professional. Review by a suitably qualified professional and required site approval are necessary before field use.
11. Revision history and authorship
This reference material was written and revised with AI. It has not been verified or approved by a professional. Review by a suitably qualified professional and required site approval are necessary before field use.
Korean source created 2026-09-20. This US edition adapts the Korean source; earlier editorial revisions do not constitute professional approval of this edition.
| Date | Edition | Change | Review status |
|---|---|---|---|
| 2026-10-12 | 1.0 | US localization: preserve task judgments; replace Korean legal applicability with scoped US references. | AI editorial and output checks; no professional technical approval. |