A 12-hour shift is not a 12-hour working day. Section 25 of the Occupational Safety, Health and Working Conditions Code 2020 fixes eight hours a day; anything beyond it is overtime under section 27, paid at twice the rate, with the worker's consent, inside a quarterly cap the rules set. The 2023 Tamil Nadu amendment that would have allowed 12-hour days was never brought into force, and the Act it amended has since been repealed. What a Chennai plant can run is an eight-hour shift with a four-hour overtime block, and the arithmetic of that is the point of this piece.
What the Code fixes, and what it leaves to the State
The Code fixes the daily limit and the overtime rate, and hands the spread-over and the cap to the appropriate government. Section 25(1)(a) says no worker shall be required or allowed to work "more than eight hours in a day"; section 25(1)(b) says the period of work in each day shall be fixed "with such intervals and spread overs, as may be notified by the appropriate Government". Section 26 limits work to six days in any week. Section 27 pays overtime "at the rate of twice the rate of wages" for work beyond the daily or weekly hours the appropriate government prescribes, calculated daily or weekly "whichever is more favourable", requires the worker's consent, and lets the appropriate government prescribe the total hours of overtime. Section 30 adds a rule that matters for contract labour specifically: no worker may be put to work in a factory if they have already worked in another such establishment within the preceding twelve hours.
The Ministry's own FAQ on the Code (January 2026) frames the flexibility as "8 hours per day and 48 hours per week as standard, with some flexibility to extend daily hours with the consent of workers on payment of overtime, at twice the rate wages" (Q3). Its March 2026 FAQ answers the question a 12-hour roster raises directly: even where the appropriate government prescribes 12 hours as the maximum, a worker who works beyond eight hours in a day is entitled to overtime at twice the normal rate, paid at the end of the wage period (Q24). The 12-hour figure, where it appears, is the outer limit of the day including overtime, not a new standard day.
The 2023 Tamil Nadu amendment is dead law
The Factories (Tamil Nadu Amendment) Act 2023, passed by the Assembly on 21 April 2023, would have let the State exempt factories from the daily-hours limits of the Factories Act 1948 so that a 12-hour day could be worked with consent, on a four-day week. The Government announced three days later that it would not be brought into force, after opposition from unions and from parties on both sides of the House [VERIFY: dates from trade-press reports of April 2023; the Act and the withholding order were not opened]. It was never notified.
It is now moot in any case. Section 143(1)(a) of the OSH Code repeals the Factories Act 1948 from the date the Code commenced, which was 21 November 2025, so an amendment to that Act has nothing left to amend. A plant that has heard "Tamil Nadu allows 12-hour shifts" has heard about a law that was never in force under a statute that no longer exists. The live question is what the OSH rules say, and there are two sets to read.
Central sphere and Tamil Nadu, side by side
For a private factory in Tamil Nadu the appropriate government is the State, so the operative rules will be the Tamil Nadu ones. Those exist only in draft: the Occupational Safety, Health and Working Conditions (Tamil Nadu) Rules 2022, published for objections in G.O. Ms. No. 38 of 11 April 2022 [VERIFY: whether Tamil Nadu has since notified final rules, and whether the draft figures survived]. The Central Rules, notified as G.S.R. 345(E) on 8 May 2026, bind central-sphere establishments only, but they show where the Centre has landed, and the two drafts were written from the same template.
| OSH Code 2020 | OSH (Central) Rules 2026 and notifications | Tamil Nadu draft rules 2022 | |
|---|---|---|---|
| Daily hours | 8 hours (s.25(1)(a)) | 8 hours; overtime beyond 8 for a daily wager (r.69(1)) | 8 hours; overtime beyond 8 in a day or 48 in a week (draft r.30(1)) |
| Weekly hours | Six days a week (s.26); weekly figure left to rules | 48 hours (r.64(1)) | 48 hours (draft r.27(1)) |
| Spread-over | Notified by the appropriate government (s.25(1)(b)) | Not yet notified for the central sphere [VERIFY: no spread-over figure found in G.S.R. 345(E) or S.O. 2517(E)] | 12 hours in a day inclusive of rest (draft r.27(2)); 14 hours in twelve listed circumstances (draft r.30(4)) |
| Rest interval | Notified by the appropriate government (s.25(1)(b)) | No more than 5 hours' continuous work, then at least half an hour (S.O. 2517(E), 13 May 2026) | No more than 5 hours' continuous work, then at least half an hour (draft r.27(3)) |
| Longest day | 8 plus overtime | Not fixed by rule; the 12-hour ceiling in r.69(4) applies to dock, mine and construction work | 12 hours of work, only in the twelve circumstances in draft r.30(4) |
| Overtime rate | Twice the rate of wages (s.27) | Twice, paid at the end of each wage period; 15 to 30 minutes rounds to half an hour (r.69(1), (2)) | Same (draft r.30(1), (2)) |
| Overtime cap | Prescribed by the appropriate government (s.27, second proviso) | 144 hours in any quarter (r.69(4), proviso) | 125 hours in any quarter (draft r.30(4), proviso) |
| Consent | Required (s.27, first proviso) | Required | Required |
| Two employers in a day | Barred within 12 hours of the other job (s.30) | Exemption circumstances for mines (r.70) | With the Inspector-cum-Facilitator's prior approval, and not more than 8 hours in all (draft r.31) |
Three things stand out. The Tamil Nadu draft allows a 12-hour working day only in the twelve circumstances it lists, which are the Factories Act exemptions of old: urgent repairs, continuous processes, seasonal work, breakdowns, loading and unloading, "exceptional pressure of work". A steady-state production roster is not on that list. Second, both caps are quarterly and small: 125 hours across thirteen weeks is under ten hours of overtime a week; 144 is eleven. Third, the Central Rules restrict their equivalent of the 12-hour provision to docks, mines and construction, which leaves an ordinary central-sphere factory at eight hours plus whatever overtime the cap allows and nothing written on spread-over at all.
What a 12-hour roster actually costs and requires
Take a worker on ₹600 a day for eight hours, which is ₹75 an hour, a round figure and not a rate this site quotes for anything. A 12-hour shift is eight hours at ₹600 plus four hours of overtime at ₹150 an hour, ₹600 more: the shift costs ₹1,200 and the fourth quarter of the day costs as much as the first three. A four-day week of 12-hour shifts is 48 hours of work paid as 64, and it uses 16 overtime hours a week; under the Tamil Nadu draft cap of 125 a quarter that roster is legal for under eight weeks in thirteen, and under the central cap of 144 for nine. A site that plans 12-hour shifts as the standard pattern has planned to breach the cap by the middle of the quarter.
Against a two-shift eight-hour pattern the comparison is a headcount one. Covering 24 hours with two 12-hour shifts uses two crews and pays each 1.5 days for a day's attendance; covering it with three eight-hour shifts uses three crews at straight time. The overtime premium is exactly the cost of the third crew's wages, before the third crew's onboarding, PF and ESIC are counted. Where the site has a genuine surge inside one of the listed circumstances, the overtime block is the right tool, and the seasonal-bench post on this site is about sizing it; where the site simply wants fewer people on the books, the arithmetic does not support it.
- Consent, in writing, per worker. Section 27 makes overtime conditional on the worker's consent. A line in the appointment letter is the minimum; a roster the worker has signed is better.
- The overtime register. Both rule sets require it (Central Form XV; Tamil Nadu draft Form VII), and it is the document an Inspector-cum-Facilitator reads first. Hours, rate, and the date paid, per worker, per wage period.
- Overtime allowance in the wage definition. The Ministry's March 2026 FAQ (Q1a) treats overtime allowance as part of the components tested against the 50% rule in the definition of wages; the article on that rule on this site explains what it does to PF and gratuity.
- Parity for contract labour. The Tamil Nadu draft requires a contractor's workers on the same or similar work to have the same hours of work and conditions as the principal employer's direct workers [VERIFY: draft rule number]. A 12-hour roster for the contract crew beside an eight-hour one for the permanent crew is the pattern that rule is written against.
- The twelve-hour gap. Section 30 bars work in a factory within twelve hours of work in another. A contract worker on a 12-hour shift cannot lawfully be on another site's roster the same day, and the contractor's attendance system is the only place that check can be made.
- Nights. Section 28 counts hours after midnight in the previous day and starts the weekly holiday from the end of the shift; women on night work need written consent and transport (Ministry FAQ, January 2026, Q4).
Whether a particular process falls within one of the listed circumstances, and what the final Tamil Nadu rules will say when they are notified, are questions for the site's own counsel and the Labour Department, not for this article.
Sources
- Occupational Safety, Health and Working Conditions Code, 2020 (Act 37 of 2020), Gazette text hosted by DGFASLI — ss.25, 26, 27, 28, 30 (hours, weekly holiday, overtime, night shifts, double employment), s.143 (repeal of the Factories Act 1948). Opened and read.
- Occupational Safety, Health and Working Conditions (Central) Rules, 2026, G.S.R. 345(E) dated 8 May 2026, Gazette of India Part II s.3(i) No. 311 — r.64 (48 hours a week), r.69 (overtime rate, rounding, listed circumstances, 144-hour quarterly cap), r.70. Opened and read from a mirrored copy of the Gazette [VERIFY: against the e-Gazette original].
- Ministry of Labour and Employment, notification S.O. 2517(E) dated 13 May 2026 under s.25(1)(b) — not more than five hours' continuous work with an interval of at least half an hour, in force 14 May 2026 [VERIFY: read via a secondary reproduction; the Gazette copy was not opened]
- Occupational Safety, Health and Working Conditions (Tamil Nadu) Rules, 2022 (draft), G.O. Ms. No. 38, Labour Welfare and Skill Development (H2), 11 April 2022, Tamil Nadu Government Gazette Extraordinary No. 216 — draft rr.27, 28, 30, 31 and the contract-labour conditions-of-service rule. Opened and read. Draft only.
- Ministry of Labour and Employment, FAQs on the OSH Code, 2020 (January 2026) — Q3 (hours flexibility), Q4 (women on night work). Opened and read.
- Ministry of Labour and Employment, Additional FAQs on Labour Codes (as on 16 March 2026) — Q1a (overtime allowance and the wage definition), Q24 (overtime beyond eight hours where 12 is the prescribed maximum). Opened and read.
- Factories (Tamil Nadu Amendment) Act, 2023 — passed 21 April 2023, implementation withheld 24 April 2023 [VERIFY: from trade-press reports; the Act and the Government's announcement were not opened]