Sourcing and buying guides

Every guide PES Supply publishes for contractors, integrators and facilities teams - grouped by the decision you are actually making. Each one explains what to check before you specify or order, and links the stock we hold. For line-item trade pricing on any list, use the quote desk.

Solar modules

• 300-400W panels - Retrofit and budget arrays where smaller modules fit legacy rail spacing.
• 400W panels - The volume workhorse class: 20-24 modules for an 8-10kW roof.
• 450-550W panels - Mainstream commercial class - fewer modules, less labor per kW.
• 550W-700W panels - Ground-mount and large commercial: footprint and 1500V discipline.
• 700W+ panels - Utility-scale formats, longer strings, equipment-assisted handling.

Inverters and controllers

• Microinverters - Module-level conversion, rapid shutdown built in, per-panel monitoring.
• String inverters 7.6-11.4kW - The residential workhorse size class and its MPPT limits.
• Hybrid inverters 3-8kW - Cabin and small-home systems with battery input built in.
• Hybrid inverters 10-12kW - Whole-home backup with a 10-15kW array and battery bank.
• Commercial inverters 12kW+ - Three-phase, 480V, DC/AC ratio and interconnection standards.
• Off-grid inverter/chargers - Standalone systems: charging, transfer behaviour and battery profiles.
• MPPT controllers 60-100A - Rated by output current, not array watts - sizing at 12/24/48V.

Generators and transfer equipment

• Standby 14-22kW - Whole-home backup once load management is in the design.
• Standby 22-26kW - Top of air-cooled residential, entry to light commercial.
• Commercial 30kW+ - Liquid-cooled systems: fuel autonomy, rigging, emissions permitting.
• Portable 2-7kW - Job sites and short outages: starting watts and CO safety.
• Portable 7-12kW - Real backup power in a portable package with a transfer switch.
• 200A transfer switches - Service-entrance vs standalone, NEMA ratings, load management.

Generator sizing, fuel and warranty

• Standby generator sizing - from service amperage to kW - load calculation, motor starting, transfer switch rating and the fuel derate.
• Generator fuel and tank sizing - propane consumption by size class, tank vaporization limits and how many days of runtime a tank really buys.
• Generac extended warranty - the 5/7/10-year extension price ladder, the year-one activation deadline and what actually voids a claim.

Storage

• 48V LiFePO4 banks - Standard off-grid bus voltage: usable capacity and BMS protocol.
• 100-200Ah batteries - Cabins, vans and small backup banks - LFP vs AGM.
• 200Ah batteries - The workhorse capacity for off-grid and mobile systems.

Racking, wire and balance of system

• Racking rail and clamps - Roof attachment, wind/snow spans and clamp zones.
• Ground-mount racking - Piles vs ballast, soil reports and array geometry.
• PV wire and THHN - Voltage rating, sunlight resistance and ampacity derating.
• Electrical supplies - Boxes, lugs, disconnects and the parts that finish a job.
• BOS accessories - Combiners, disconnects, monitoring and cable management.

Kits and EV

• Pre-configured solar kits - Compatibility risk moves to the supplier - landed cost matters.
• Level 2 EV chargers - 40A vs 48A, circuit sizing and rebate eligibility.

Brand hubs

• Generac generators - The full Generac line: standby, portable and transfer switches.

Recent sourcing articles

• Wholesale solar panel pricing in 2026 - quantity tiers, freight class and vintage risk.
• Buying a standby generator at wholesale - sizing, fuel, transfer switch and freight.
• Solar kit vs component build - where each path quietly adds cost.

Design and specification

• Reading a solar panel datasheet - the five numbers that actually decide string length, conductors and inspection.
• 48V vs high-voltage battery architecture - the first battery decision: inverter shortlist, conductor cost and expansion path.

Commercial systems and compliance

• Commercial BESS sizing - from interval data to interconnection; demand shaving, TOU arbitrage and NFPA 855.
• Buying refrigerant wholesale - the EPA 608 certificate gate, cylinder rules and DOT hazmat shipping.
• Buy America(n) documentation - the paperwork a federally funded solar bid actually needs.

Design, conductors and freight

• Sizing PV and battery conductors - ampacity, conditions-of-use derating and voltage drop in the right order.
• Off-grid cabin design - loads, autonomy, winter array derating and generator backup.
• Module freight economics - pallet quantity, delivery conditions and staging versus landed cost.

System economics and design ratios

• DC/AC ratio and clipping - why oversizing DC is normal, and when clipping actually costs money.
• Export rates and system economics - how falling export credit shifts the design from production to self-consumption.

Loads, structure and electrification

• Generator sizing for motor loads - starting watts, locked rotor and why load management beats a bigger unit.
• Racking wind and snow loads - the design inputs a permit reviewer wants, and the clamp-zone trap.
• Heat pump + solar panel capacity - Article 220 load math, the 120% busbar rule and load management.

Installation and logistics

• Level 2 EV charger installation - 48A needs a 60A circuit: service capacity, the 120% busbar rule and load management.
• Freight damage and shortages - how to document at delivery so a claim actually pays.

Datasheets and remote sites

• Reading an inverter datasheet - MPPT window, max DC voltage, per-MPPT current, derating and weighted efficiency.
• Telecom and remote site power - DC load profile, autonomy, worst-month insolation and chemistry in cold climates.