One of the most frequent questions engineers ask before inspecting Data Center ATS / STS Fast Transfer Test Report is: "Which standard should I cite on the certificate, and where do the pass/fail limits come from?" This reference guide maps IEEE 3008 / ANSI-TIA-942 to national regulatory adoptions and provides the complete standard annex tables.
1. National & Regional Standard Equivalence Matrix
| Region / Language | Adopted National Standard & Regulatory Code |
|---|---|
| International / UK (EN) | IEEE 3008 / ANSI-TIA-942 |
| Turkey (TR · Türkçe) | TS EN 60947-6-1 / IEEE 3008 / ANSI-TIA-942 |
| Germany / DACH (DE · Deutsch) | DIN EN 60947-6-1 (VDE 0660-114) / IEEE 3008 |
| France (FR · Français) | NF EN 60947-6-1 / IEEE 3008 / ANSI-TIA-942 |
| Spain (ES · Español) | UNE-EN 60947-6-1 / IEEE 3008 / ANSI-TIA-942 |
| Italy (IT · Italiano) | CEI EN 60947-6-1 / IEEE 3008 / ANSI-TIA-942 |
| Gulf / Middle East (AR · العربية) | IEEE 3008 / ANSI-TIA-942 / SASO / DEWA / ADDC |
2. Normative Acceptance Criteria & Mathematical Basis
A static transfer switch must complete the transfer inside a quarter cycle so the load stays within the ITIC ride-through envelope; an engine-generator EPSS must accept load within 10 s for a Type 10 system (NFPA 110).
t_STS_max: t_STS <= 250 / f_Hz [ms] — Maximum break time for static silicon-controlled rectifier (SCR) transfer without dropping single-corded IT PSU loads.
3. Official Standard Reference Tables
ITIC (CBEMA) Voltage Dip Ride-Through Envelope & Transfer Limits (IEEE Std 1100 (Emerald Book) / IEEE 3008)
| Disturbance / Switch Type | Duration Window | Permissible Voltage Dip / Break | Typical Equipment |
|---|---|---|---|
| Sub-cycle Interruption / STS Transfer | <= 20 ms (1 cycle at 50 Hz) | Up to 100% dip (zero voltage ride-through) | STS (typically 4 - 6 ms) |
| Short Voltage Sag | 20 ms to 500 ms | Remaining voltage >= 70% (Dip <= 30%) | Closed-transition ATS (< 100 ms) |
| Long Voltage Sag | 500 ms to 10 s | Remaining voltage >= 80% (Dip <= 20%) | Motor starting / utility fault clearing |
| Open Transition EPSS Start | <= 10,000 ms (10 s) | Full break (UPS bridges gap) | NFPA 110 Type 10 Generator ATS |