Wiring devices, floor boxes and desk power modules are bought in volume from manufacturers and authorised distributors, which is where consolidated buying makes a visible difference on large seat counts.
UPS, distribution boards and PDUs are sourced through authorised channels with commissioning and service support included, because after-sales response matters more than the last few percent on price.
Direct manufacturer supply is used where it is genuinely available for the category and volume. Where a brand supplies only through authorised partners, we buy that route to protect warranty and benchmark it so the difference is visible.