Standards library
The codes, standards bodies, and reference organizations our calculations are grounded in. We link to the primary source so you can go straight to the authority.
NEC — National Electrical Code (NFPA 70)
The governing code for electrical installations in the US. Defines conductor ampacity, overcurrent protection, EV charging equipment rules (Article 625), and load calculation methods (Article 220) that our residential and commercial tools reference.
IEEE 3006 / 519
IEEE 3006 covers reliability and load analysis for industrial and commercial power systems; IEEE 519 governs harmonic distortion limits — both relevant when sizing grid-connected loads like data centers and large motor banks.
ASHRAE 90.4 & Thermal Guidelines
ASHRAE's Thermal Guidelines for Data Processing Environments define safe inlet temperature/humidity envelopes for IT equipment, and Standard 90.4 sets minimum energy efficiency (including PUE-adjacent metrics) for data center facilities.
ENERGY STAR
A US EPA/DOE program certifying energy-efficient appliances, electronics, and equipment. Typical wattage figures in our field references are cross-checked against ENERGY STAR product data where available.
DOE / EIA — U.S. Department of Energy & Energy Information Administration
The EIA publishes average residential and commercial electricity rates, generation mix, and consumption data used as defaults in our cost-estimation calculators.
IEC 60364 & IEC 62196
International equivalents to the NEC for electrical installations, plus the IEC 62196 standard defining EV charging connector types (Type 1/2, CCS) used outside North America.
SAE J1772 & CCS/NACS
SAE J1772 defines the standard AC charging connector for Level 1/2 EV charging in North America; combined with CCS and the newer NACS (Tesla-derived) connector for DC fast charging.
AHRI Standards
The Air-Conditioning, Heating, and Refrigeration Institute certifies performance ratings (EER, SEER, COP) for cooling equipment — the basis for the electrical-draw-per-ton figures used in our cooling calculators.
WattThe?! is an independent educational resource and is not affiliated with, endorsed by, or a publisher of any of the standards listed above. Always consult the current published edition and a licensed professional for code-compliance decisions. See also Calculation methods.