Regional & International Design Deltas: Consolidated Quick-Reference Crosswalk

This guide is deliberately global, and regional content sits in the Parts where it belongs. Siting and water are in Part 3, the power chain in Part 4, cooling in Part 5, the building in Part 6, and sustainability and reporting in Part 15. This appendix is the consolidated crosswalk, a dense reference that gathers those scattered deltas into tables you can read at the bench. It shows how the engineering shifts across a border and does not replace the chapters that own it. Every row points back to the chapter where the decision is made.

Each delta re-decides something downstream. A 50 Hz grid changes transformer flux, generator sizing and harmonic spectra (Part 4). An IEC code family changes cable derating, fire strategy and the meaning of "redundancy class" (Parts 4 and 6). A tropical climate reduces many economizer opportunities and changes the trade among dry, wet, hybrid and compressor-led plants. Water law and the annual weather and load model then select the viable operating point (Parts 5 and 3). Read the tables as forward pointers to the chapters they reference, not as a substitute for them.

Frequency, nominal service voltage, installation code, product conformity and earthing are separate design-basis fields. None can be inferred from an 'IEC world' or 'ANSI world' label, so record the serving utility and jurisdiction for each. Japan is split between 50 Hz in the east and 60 Hz in the west. Saudi Arabia is 60 Hz and is moving new supply toward 230/400 V, while 127 V remains in legacy areas. The UAE, Qatar, Kuwait, Bahrain and Oman are 50 Hz but keep distinct voltages, wiring rules and utility requirements. GCCIA therefore links the Saudi and other GCC systems through back-to-back HVDC. Confirm the exact site basis rather than copying a regional template.

Load ride-through is a sixth field that changes between grids. Ireland's Grid Code modification MPID 345 takes effect on 27 October 2026 for existing and new transmission-connected demand. Those facilities must ride through specified faults and ±1 Hz/s rate-of-change-of-frequency events without disconnecting. Once voltage recovers to 0.9 per unit, at least 90% of pre-fault demand must be back within 500 ms. In the US, ERCOT NOGRR282 (new large computational loads, from 1 August 2026) and SPP large-load rules are in force, and a PJM rule is proposed. NERC’s computational-load standards passed final ballot in October 2026 but set no ride-through curve, and FERC RD26-7-000 sets no ride-through thresholds either. UPS and transfer thresholds, controls and power-electronics settings follow the grid code you connect to. At commissioning, test two things: the site transfers cleanly to backup for disturbances beyond the grid code’s ride-through curve, and it stays connected through normally cleared faults and sags within it (4.10, 13.6).

The second boundary is the law and code edition adopted by the site authority. In the United States, use the NEC edition and amendments adopted by the state or local AHJ, plus the applicable NFPA, building, fire and product-listing requirements. Canada uses CSA C22.1, Canadian Electrical Code Part I, as adopted and amended by each province or territory, with Canadian building, fire and certification requirements. Mexico uses NOM-001-SEDE plus national, utility and local requirements. In the EU, HD 60364 is implemented through national standards and law. The UK separately uses statutory duties, BS 7671 and DNO rules. No single 'North American' or 'IEC' label is an enforceable project code basis.

For UK installation work, BS 7671:2018+A4:2026, published in April 2026, is the current edition. BSI withdrew the previous edition, BS 7671:2018+A2:2022+A3:2024, on 15 October 2026. For the six months before that, the IET allowed installers to use either edition (IET transition receipt). Before accepting cable, battery or earthing design, pin the project edition and open the clauses.

Beyond frequency and code family, each major region has its own regulatory, grid and water signature. Those signatures reshape siting (Part 3) and energy strategy (Parts 3 and 4) more than any electrical delta does. The table below is the at-a-glance screen for the regions most active in the 2025–2026 AI build-out. Figures are cited inline, and the key-numbers block consolidates the load-bearing ones.

Ireland carries its own connection policy on top of EU rules. The Commission for Regulation of Utilities (CRU) set its connection policy for large energy users in December 2025. Under it, a new data center at 10 MVA or more of maximum import capacity (MIC) must provide dispatchable on-site or nearby generation or storage that covers that MIC on a derated basis. That plant is offered to the market. At 1 MVA and above, at least 80% of annual demand must also come from additional Irish renewables within six years of energization. EirGrid still rates Greater Dublin fully constrained and assesses connections location by location. Transmission-connected demand also faces the MPID 345 ride-through rule in Crosswalk 1. The climate is temperate maritime and economizer-friendly, but use the site design conditions. Queue → 3.2; market → 3.13; self-supply → 3.4, 3.5; ride-through → 4.10.

Three markets the table omits are common next ports. Malaysia (Johor) is 230/400 V, 50 Hz, and water is now an approval gate. As Johor’s state infrastructure chairman described it on 5 January 2026, every project goes before a state Special Technical Committee, which weighs its water and electricity supply, utility issues and whether the location suits it. The state also sets a water usage effectiveness (WUE) threshold of 1.8. Where local water is short, meeting that threshold is not enough, and a project that needs cooling water has to turn to alternatives such as recycled sewage water. Nationally, MIDA said in August 2026 that Malaysia’s Data Centre Task Force clears a project only once it has secured power and water and can show green compliance. Market → 3.13; water → 3.7.

The Nordics run at 50 Hz with 230/400 V utilization, long free-cooling seasons and district-heating networks that make heat reuse a siting asset (5.9). Norway needs an earthing check: its older low-voltage networks were built largely as 230 V IT systems, with only new installations built TN, so write the earthing basis into a Norwegian design. Sweden, Finland and Denmark are EU members, so EED reporting and the Art. 26(6) waste-heat test apply there. Norway is outside the EU, so check which of those duties reach it through the EEA agreement. Norway, Sweden and Finland have all withdrawn the reduced electricity-tax rate data centers once paid, Finland on 1 July 2026, so underwrite a Nordic site at the ordinary rate (3.10). Finland’s draft law of 18 September 2026 would also sort demand and storage connection requests into four priority groups from 1 January 2027. Requests already in the queue would be re-sorted too unless they hold a concluded or conditional connection agreement (3.2).

Brazil runs at 60 Hz like the US, but its low-voltage installations follow ABNT NBR 5410, which derives from IEC 60364, and NR-10 governs electrical work safety. Utilization is 127/220 V in some states and 220/380 V in others, so neither a US nor a European template ports intact. Brazil’s Redata law (Lei 15.504, September 2026) suspends federal taxes on data-center equipment, and two of its conditions are design terms. All its electricity must come from renewable or low-emission supply, and WUE must be 0.05 L/kWh or less, which in practice means closed-loop or dry cooling (3.10). The AI campuses planned in Rio Grande do Sul and Ceará are covered in 3.13.

PUE = 100/85 = 1.176… < 1.2, so the design passes on efficiency. Both it and the limit display as about 1.2, so only the unrounded ratio decides compliance. ERF = 18/100 = 18%, below this cohort’s 20% floor. Raising useful annual reuse to 20 GWh clears it, so the heat-offtake lead must secure and meter another 2 GWh/year or establish an applicable statutory exception. A modeled heat balance alone does not release the obligation.

Keep the bill separate: facility electricity, demand and network charges and taxes belong in the supply contract, and heat-sale income belongs in the offtake contract. Stromnetz Berlin’s 2026 fee page and connection process distinguish network fees from connection and use agreements. The case assumes no tariff and forecasts no current rate forward: the project has to obtain the 2028 tariff, a signed energy offer and the heat price from the utility, the retailer and the heat buyer. Neither an EnEfG calculation nor a heat buyer secures grid service or building permission, so get the utility agreement and local approvals before promising a schedule. Chapter 3.3 owns the bill, 3.9 permits and 5.9 heat engineering.

At nominal 8.0 MW IT, 10.0/8.0 = 1.25 ≤ 1.25 passes and 10.4/8.0 = 1.30 > 1.25 fails. Equality leaves no engineering margin, and an acceptance test adds measurement uncertainty on top. To pass in the second state, the plant lead must remove 0.4 MW at that operating point and demonstrate ≤10.0 MW facility draw. The full-duty energy penalty is 0.4 × 8,760 = 3,504 MWh, about 3.5 GWh a year. At a constant marginal contract rate it costs 3,504,000 kWh times that rate; otherwise sum the hourly charges. Changed demand and network charges come on top.

SP Group’s January 2026 connection handbook requires IMDA acknowledgement in §2.3.2, and §3.1 separately covers connection agreements and use-of-system charges. The commercial lead still needs the retailer offer and the SP PowerAssets connection and use-of-system terms; colocation rent is not a proxy for them. Any future call’s allocation terms must be met separately, including eligible green-energy pathways (DC-CFA2 required at least 50%), and generic certificates do not establish that criterion. EMA’s non-residential guidance treats demand response and interruptible load as distinct participation choices, not automatic firm service. Allocation, utility service and local approvals each need separate proof before a live date. Apply Chapter 3.3 to the bill, 3.13 to the site decision and 5.8 to the plant.

The fourth delta class is climate. It reshapes cooling (Part 5), the building envelope and structure (Part 6) and the water siting gate (Part 3) more than any other. Three archetypal climate types dominate AI siting, each with its own failure mode and hardening posture. Wet-bulb temperature (WBT), not dry-bulb, governs evaporative and adiabatic cooling: a hot-arid site with low WBT can lean on adiabatic assist that a tropical site with high WBT cannot.

The climate type and the regional regulatory signature are not independent in practice. A tropical site (Singapore, Chennai) is typically also a high-WBT, water-quality-challenged, efficiency-capped jurisdiction, so the cooling, water and code deltas stack. A hot-arid GCC site still needs country-, utility- and project-specific records for frequency, voltage, earthing, power price, permitting, water and service path; neither the climate nor the GCC label supplies those values. The four classes are orthogonal as a taxonomy but correlated on the ground, which is why one consolidated reference beats four separate lookups.

The closing table inverts the crosswalks: given a Part, it names the deltas that most often force a redesign away from a US- or EU-default basis. Use it as a pre-flight check when porting a reference design to a new region.