The size of an access opening is only one part of confined-space lighting selection. Atmospheric conditions, conductive surfaces, supply and the worker's task determine what the complete setup must address.
Start with the entry assessment
Use the site's entry program and atmospheric evaluation to establish the conditions of the work. Lighting does not replace testing, ventilation, isolation or rescue planning. A space can be hazardous for reasons unrelated to flammable atmospheres.
Identify the electrical conditions
Distinguish a dry space from wet or conductive work and establish the applicable rules. For construction portable lighting in wet or conductive locations, OSHA gives a specific 12V-or-less rule and a stated 120V-with-GFCI alternative. Do not apply an unsupported universal 24V allowance.
Arrange more than one working view where needed
A hand lamp can sit beside the repair while a personal light moves with the worker. String assemblies can serve successive internal positions. Keep supports and cables clear of retrieval routes, moving equipment and sharp edges.
Verify the whole configuration
Check exact approval, lamp-side and supply voltages, transformer inclusion, cord length, connectors and permitted component locations. Low voltage alone does not establish intrinsic safety or gas/dust approval. Backup lighting needs to be selected to the site's entry and emergency arrangements rather than a generic percentage of normal output.
Compare portable confined-space lighting formats after those requirements are established.
References: OSHA 1910.146 — Permit-required confined spaces · OSHA 1910.307 — Hazardous (classified) locations · OSHA 1926.405 — Temporary wiring and portable lighting