Insights
Engineering notes on the energy transition
Practical, vendor-neutral explainers on power equipment, energy storage and EV charging — written by Entogo's engineering team to help utilities, developers and operators specify the right system.
Power Quality
Harmonic distortion: what IEEE 519 requires and how to meet it
Harmonic distortion from VFDs, EV chargers, and data-center power supplies can breach IEEE 519 limits and quietly overheat neutrals, transformers, and switchgear. This guide explains the 519-2022 voltage and current limits and how to specify mitigation before it becomes a field problem.
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Energy Storage
How to size a battery energy storage system: power vs. energy
A battery energy storage system is sized with two independent numbers, power in megawatts and energy in megawatt-hours. Their ratio is the C-rate, which fixes how long the system runs at full output and drives cost, cooling, and site design.
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EV Charging
EV charging load management: sizing a site without a service upgrade
Adding EV chargers often does not require a larger electrical service. NEC 625.42 lets an energy management system cap the combined draw, so a site can be sized to the managed load instead of the full nameplate of every charger. Here is how to decide and what to specify.
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Renewable Grid Connection
Interconnecting solar and storage to the grid: what IEEE 1547-2018 requires
Connecting solar or battery storage to the North American grid means meeting IEEE 1547-2018 for DER behavior, using a UL 1741 SB certified inverter, and passing a utility interconnection review that scales from a fast-track screen to a full study. Here is how the pieces fit.
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Power & Distribution
Arc-resistant switchgear: when it's required and what an IEEE C37.20.7 rating means
Arc-resistant switchgear redirects the pressure and heat of an internal arcing fault away from anyone standing nearby, tested to IEEE C37.20.7. It is specified where crews work close to energized medium-voltage gear and calculated incident energy is high.
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Standards & Compliance
Transformer efficiency standards: what DOE 10 CFR 431 requires and the 2029 update
US distribution transformers must meet DOE 10 CFR 431 minimum efficiency, defined at 35 percent load for dry-type units and 50 percent for liquid-immersed. A 2024 final rule raises those floors for units built on or after April 23, 2029, and here is how the rules work and what to specify.
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Power & Distribution
Power factor correction: how to clear a utility power-factor penalty
Utilities such as BC Hydro and Hydro One surcharge or re-bill on kVA when power factor falls below 90 percent. Capacitor banks raise power factor to clear the penalty, but harmonics can drive resonance, so IEEE 519 and detuned designs govern a safe install.
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Power & Distribution
Dry-type vs. liquid-filled transformers - how to choose
Dry-type transformers cool with air and solid insulation while liquid-filled units use mineral or less-flammable oil. The right pick turns on installation location, fire and code rules, voltage class, efficiency, and maintenance - not on which type is generally better.
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Energy Storage
Battery storage fire safety: what NFPA 855 and UL 9540A require
Lithium-ion battery storage in North America is governed by NFPA 855 and UL 9540A. NFPA 855 caps individual units at 20 kWh and requires three-foot separation unless UL 9540A large-scale fire-test data proves a fire will not spread, which shapes how a BESS is sited, spaced, and permitted.
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Power & Distribution
Metal-clad vs. metal-enclosed switchgear: how to choose
Metal-clad switchgear uses drawout breakers and grounded metal barriers between every compartment; metal-enclosed interrupter switchgear is simpler and built for lower fault duty. Here is how North American buyers match construction class, voltage, and fault duty to the application.
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Standards & Compliance
How do transformers get approved for use in Canada?
Before a transformer can be energised in Canada, the Canadian Electrical Code requires it to be "approved" — either certified by an SCC-accredited body (a CSA, cULus or cCSAus mark) or field-evaluated to CSA SPE-1000. A US-only "UL Listed" mark is not enough. Here is how the approval system actually works.
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Power & Distribution
Sizing transformer overcurrent protection (NEC 450.3(B) & CEC 26)
How to size transformer primary and secondary overcurrent protection to NEC Table 450.3(B) and CEC Section 26 (Rule 26-254), and how to find the available fault current at the secondary for downstream AIC / SCCR — with worked US and Canada examples.
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Sales & Distribution
How are transformers sold? Distribution channels, reps and the 2026 demand surge
Transformers reach buyers through four channels: direct OEM sales to utilities and EPCs, independent manufacturers' reps, two-step electrical distribution, and online procurement. With a global market near US$61B and 30% power-transformer supply deficits, the sales channel and sourcing have become strategic.
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Power & Distribution
How to size a transformer: a practical guide to kVA selection
How to convert a real electrical load into the right transformer kVA: the calculation, the standard ANSI/IEEE rating ladder, and the margins for continuous duty, future growth, ambient and altitude that sit between calculated load and nameplate.
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AI & Data Centers
Power equipment for AI data centers: what changes when racks hit 100 kW
AI training loads have pushed rack densities past 100 kW and substation lead times past three years. This is what each layer of the data-center power chain — transformer, switchgear, energy storage — now has to deliver, and where projects actually compress the schedule.
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EV Charging
What does it actually cost to install a DC fast-charger station? A 2026 breakdown
Public ranges for "DC fast-charger installation cost" span $50,000 to over $1 million per site — too wide to be useful. The Atlas/Paren analysis of NEVI awards, NREL deployment data and Rocky Mountain Institute rate-design work converge on a tighter cost stack, and on which lines actually move.
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Market & Supply Chain
Grain-oriented electrical steel: why one Pennsylvania mill sets the clock for the North American grid
Every power transformer needs grain-oriented electrical steel (GOES), and the DOE estimates it is roughly a quarter of large-transformer cost. North America has one domestic producer — Cleveland-Cliffs' Butler Works. This is the supply chain behind the one-to-four-year lead time.
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Market & Supply Chain
How long are transformer lead times in North America in 2026?
In 2026, transformers in North America's merchant market commonly take one to four years to deliver — driven by electrical-steel (GOES) constraints, surging data-center demand and an aging fleet. Manufacturers with their own source factory, such as Entogo at a 12-week standard lead time, sit largely outside that queue.
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Solar-Storage-Charging
Solar-storage-charging integrated systems, explained
A solar-storage-charging system pairs on-site PV, a battery and EV charging behind a single grid connection, so charging draws on stored solar instead of the service entrance — enabling fast charging at sites whose utility supply could not sustain it alone.
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Energy Storage
How behind-the-meter battery storage cuts demand charges
Demand charges are billed on a facility's highest power draw, not its total energy use. Behind-the-meter battery storage discharges during those brief peaks to cap the demand, and shifts cheap off-peak or solar energy into expensive on-peak hours — lowering both parts of a commercial electricity bill.
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EV Charging
AC vs. DC EV charging: what North American sites need
AC charging is slower, cheaper and ideal where vehicles dwell for hours; DC fast charging delivers high power for short stops but needs far more grid capacity. Matching charger type to dwell time, site load and budget is the first decision in any EV charging project.
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Power & Distribution
Prefabricated substations vs. conventional builds: when modular wins
A prefabricated substation arrives as a factory-built, factory-tested package that drops onto a prepared pad, compressing months of on-site construction into days. For space-constrained, schedule-driven or repeatable projects, the modular approach usually wins on time, quality and total cost.
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