Guides & References

Everything Voltfield has written down

Eighteen guides explaining how this equipment actually behaves, and seventeen equipment references covering what you can specify. No signup, nothing for sale.

Transformers & substation

How to Read a Transformer Nameplate

kVA ratings, cooling class codes, impedance, BIL and vector group: what every field means and which ones decide the rest of your design.

Pad-Mount vs GSU Transformers

They solve different problems and carry very different lead times. How to tell which one your application actually needs.

Why Transformer Lead Times Hit 3+ Years

What is driving the multi-year power transformer shortage, and how to sequence a project around it.

Switchgear & protection

Metal-Clad vs Metal-Enclosed Switchgear

How the standards define them, what sits inside each compartment, and why the distinction changes what you can safely work on.

Short-Circuit Studies & Breaker Coordination

What a short-circuit study calculates, why a quick fault-current estimate is not a substitute, and how coordination follows from it.

Arc-Flash Boundary Basics

What an arc-flash boundary is, how it relates to incident energy, and what NFPA 70E requires on equipment labels.

Grounding & Bonding Basics

They do two different jobs. What each actually does, and why the equipment grounding conductor is not the neutral.

Data center power & cooling

PUE Explained

The formula, what counts as facility power, typical ranges from 1.1 to 2.0, and what actually drives the number.

Liquid vs Air Cooling for AI Racks

Why GPU rack density is pushing data centers to liquid: direct-to-chip, immersion and rear-door heat exchangers compared.

Renewables & storage

Inverter Clipping & DC:AC Ratio

Why utility-scale solar oversizes the DC array on purpose, how clipping works, and the ratios typically used.

BESS Augmentation Explained

Why lithium capacity fades, how augmentation plans for it with phased DC block additions, and what that means contractually.

BESS Fire Safety: NFPA 855 & UL 9540A

What NFPA 855 requires for battery storage installations, and how UL 9540A test data sets separation distances.

Grid interconnection

The Grid Interconnection Process

What happens between filing a request and energizing: queue position, the study sequence, and where projects stall.

PJM Interconnection Timeline

How the PJM queue works: Transition Cycles, readiness requirements, and what Northern Virginia data-center load has done to it.

MISO Interconnection Timeline

How the MISO Definitive Planning Phase works, why cycles ran years behind schedule, and why sub-region matters.

ERCOT Interconnection Timeline

Why ERCOT sits outside FERC jurisdiction, how connect-and-manage differs, and why stability screening still bites.

Procurement & compliance

Buy America (BABA) for Procurement

What Build America, Buy America requires for IIJA-funded projects, and how it differs from the IRA domestic-content rules.

FEOC Compliance for Solar & Storage

What FEOC rules mean for procurement, what documentation to gather, and how they interact with domestic content.

Equipment references by sector

Each sector page covers the engineering behind the equipment; the pages beneath it go deeper on one equipment class.

Data Centers

Pad-mount vs GSU transformers, N/N+1/2N redundancy, switchgear, backup power and cooling.

Transformers · Switchgear · Backup Power · Cooling · Power Distribution · Cabling

Renewables

DC:AC ratio and clipping, fixed-tilt vs tracker, GSU transformers and collection systems.

Solar Inverters · DC Collection · AC Collection

Battery Storage

Duration and C-rate, grid-forming vs grid-following PCS, augmentation and fire safety.

PCS & Inverters · Enclosures · Balance of Plant

Oil & Gas

Wellheads, BOPs, OCTG tubulars, artificial lift and frac valves across API specs.

Industrial Supply (MRO)

Fasteners, raw materials, safety and PPE, tools, plumbing and electrical distribution.

Equipment deep-dives

Data Center Transformers

Pad-mount, large power, dry-type and K-rated compared, with indicative lead times.

Data Center Switchgear & Breakers

MV switchgear, LV switchgear, air circuit breakers and MCCBs.

Backup Power: Gensets & UPS

Diesel and gas gensets, turbines, static UPS and flywheel systems.

Data Center Cooling

CDUs, CRAH/CRAC units, rear-door heat exchangers and chillers.

Power Distribution: Busway & PDUs

Busway, floor PDUs, RPPs, static transfer switches and rack PDUs.

Cable & Busbar Sizing

MV and LV power cable, copper busbar and fibre trunks, with ampacity guidance.

Transformer Components

Bushings, tap changers, radiators, insulating fluid, core steel and winding conductor.

Switchgear Components

Instrument transformers, trip units, contact and arc-chute kits, enclosure hardware.

Genset Components

Engines, alternators, controls and governors, cooling, exhaust, fuel and starting.

Grounding & Bonding

Ground bars, exothermic connections, earthing kits and surge protective devices.

Monitoring & Controls

Revenue and power-quality metering, and the protective relays behind breaker operation.

Solar Inverters

String, central, commercial and hybrid PV inverters: ratings and MPPT granularity.

PV Combiners & DC Cable

String combiners, recombiners, PV wire and rapid shutdown at 1500V.

Solar AC Collection

Pad-mount step-up transformers, collector feeders and collector switchgear.

BESS Power Conversion (PCS)

Central, modular and grid-forming PCS, with UL 1741 SB considerations.

BESS Enclosures & Modules

Containerized enclosures, battery modules and fire protection.

BESS Balance of Plant

MV step-up transformers, collector switchgear, protection relays and station service.

Calculators explained

Each page covers the method, the formula, a worked example you can check against the tool, the governing standard, and what the calculation does not account for.