Picture a food plant on the Bogota plateau at 2:07 p.m. The grid drops and a clock starts running: ten seconds. An automatic transfer switch panel (ATS) is the low voltage assembly that senses the utility failure, starts the standby generator and moves the load across with no one touching a thing. Here is what the 2026 RETIE (Colombian Technical Regulation for Electrical Installations) demands of it and how to specify it.
Why now: according to XM, operator of Colombia's National Interconnected System, as reported by Infobae on 27 September and Pulzo on 6 October, September set the highest demand in the country's history, and its bulletin 359 of 11 September estimates a firm energy gap of 7,207 GWh-year (7.76 %) for 2026-2027. The national weather institute (IDEAM) puts the odds of a very strong El Niño at 90 %, which is why every plant manager should now ask what an automatic transfer switch panel is worth. More in rationing risk in 2027.
It monitors two sources, decides and operates. Its product standard is IEC 60947-6-1 (International Electrotechnical Commission), edition 4.0 of 2 April 2026, or the North American UL 1008; RETIE lists both among the applicable standards.
It has a controller, switching by circuit breakers or contactors, and an interlock that stops the two sources from closing at once. The regulatory requirement: emergency source in no more than 10 s. Typical manufacturer ranges (Cummins), which are not meant to be added at their maximums:
Open and delayed. The short answer: open in most cases, and delayed with large motors. Open transition breaks before it makes, so there is a gap in supply during the operation and never a paralleled source. Delayed transition adds a timed neutral position (I-0-II), because a disconnected motor keeps generating voltage and, reconnected out of phase, draws more than its starting current. The TSEWG (Tri-Service Electrical Working Group, USA) criterion is to reconnect below 0.25 per unit (pu) residual voltage, which decays in 1 to 2 s; 5 to 10 s is recommended.
Closed. Makes before it breaks: the sources overlap for 100 ms or less, synchronized within windows of about ±5 % in voltage, ±0.2 Hz and ±5° (EGSA, the generator-set trade association; values vary by manufacturer). It usually needs the grid operator's permission and extra protection. For loads that cannot tolerate even a brief gap, a UPS (uninterruptible power supply) and an STS (static transfer switch) come in. All of this is settled in the project specification.
Answer first: 4 poles (switched neutral) when the generator is grounded as a separately derived system, especially with ground fault protection (GFP) at the service entrance; 3 poles with a single neutral-to-ground bond.
With 3 poles and the neutral grounded at two points, neutral current finds two return paths and the GFP can trip falsely. The NEC requires GFP (230.95) on wye services above 150 V to ground and rated 1,000 A or more. Use the same number of poles in every automatic transfer switch panel in the installation: mixing them can compromise the GFP.
Answer first: unless it uses circuit breakers (CB class), the ATS does not protect anything; it withstands the fault until the upstream protection clears it.
Under IEC these are the Icw (rated short-time withstand current, kA for 0.1, 1 or 3 s; the Ectricol datasheet declares up to 65 kA for 1 s) and the Icm (rated short-circuit making capacity, a peak value). Under UL 1008 it is the WCR (Withstand and Closing Rating): time-based (for example 3 cycles, 50 ms) or short-time up to 0.5 s. The rule: a rating equal to or above the short-circuit current at the terminals, and a time equal to or above the upstream clearing time. To read these values, see Icw, Ipk and Icc on the nameplate (in Spanish).
Answer first: an exclusive product certificate, a module compliant with standards such as IEC 60947-6-1 or UL 1008, and a manual listing the programmed parameters. Current text: Resolution 40284 of 23 June 2026, in the compiled RETIE from the Ministry of Mines and Energy.
What RETIE says about the automatic transfer switch panel (2026 compilation)
In healthcare, Resolution 3100 of 2019 requires a standby generator for surgery, emergency rooms, dialysis and the cold chain. Where large motors are present, common in industry, oil & gas and mining, delayed transition is worth evaluating. The datasheet of the Ectricol transfer switchboards declares up to 480 V AC and 5,000 A, Icw up to 65 kA for 1 s, IP up to 66, IK up to 10, utility/utility, utility/generator and generator/generator schemes, and type tests per IEC 61439-1 and NTC 3278; the family sits in low voltage.
Specification lesson. Before quoting an automatic transfer switch panel, settle five data points and demand them from any supplier: (1) short-circuit current at the terminals and upstream clearing time, for an Icw/Icm or WCR equal or higher; (2) with a generator as a derived system or GFP, 4 poles and the same configuration on every ATS; (3) with large motors, delayed transition with a 5 to 10 s neutral position; (4) 10 s restoration for emergency and hospitals (RETIE 3.28.4.8 g and 3.28.3.2 c) and a bypass if the load cannot be shut down; (5) an exclusive RETIE certificate, a manual with the programmed parameters and a timed FAT (factory acceptance test) protocol.
One boundary: this article explains the technology and the standard; the nameplate values of each automatic transfer switch panel are those of its datasheet and its test documentation. Industrias Ectricol S.A.S. manufactures in Funza, Cundinamarca, and its engineers review every case.
A low voltage assembly that detects the utility failure, starts the generator and hands it the load with no human intervention. Its product standard is IEC 60947-6-1 or UL 1008.
The requirement is 10 seconds in total at most. The typical manufacturer ranges (0 to 1 s, 4 to 8.5 s and 0.5 to 1.5 s per stage) are tuned so the total stays within 10 s.
Open disconnects one source before connecting the other, so there is never a parallel. Closed overlaps them for 100 ms or less, with no gap, normally with the grid operator's permission.
When the generator is grounded as a separately derived system, especially with ground fault protection (GFP): with 3 poles, the GFP can trip falsely.
Could your plant, clinic or data center last ten seconds without the grid?
Tell us about your installation (sources, loads and short-circuit current) and our engineers will review what the datasheet of the automatic transfer switch panel covers.
Talk to a specialist See transfer switchboardsA switchboard labeled “IP67” may not survive a hose-down, because what was tested was immersion, and the nameplate does not even say whether it can take a hit. The ingress protection rating (the IP...
Keep readingOn 4 June 2022, in Odessa, Texas, a surge arrester failed and caused a single phase to ground fault on the 345 kV system. Protection cleared it in three cycles, and the system still lost 2,555 MW: the grid...
Keep reading