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Every generator we sell, new or used, is tested under real electrical load to confirm it holds 100 percent of its rated output, not just that it starts. New units are tested regardless of prior factory testing, and used units are tested based on known service history or a direct hands-on check. Each unit ships with a documented test report, so you know exactly what was tested and how it performed before it reaches your site.
Why an Untested Generator Is a Real Risk
A generator that starts is not the same as a generator that performs under load. Testing confirms a unit will hold its full rated output, not just that it turns over and idles.
WPP tests every generator it sells, new or used, before it ships. Finding a problem in our yard, rather than after a unit is installed, is the reason we test.
WPP’s Testing Process: An Overview
Every new generator is tested in our shop before it leaves, even when the manufacturer already tested it at the factory. Our shop verifies the unit’s settings against its voltage specification, then load bank tests it to confirm it holds 100 percent of rated capacity before it ships.
Used units follow a condition-based process. When WPP already knows a unit’s history, from selling and maintaining it new, or from servicing it on a prior job, that history may stand in for re-running the full new-unit process.
When a unit’s history is not known, technicians test it directly for start-up and load-holding capability, and repair the unit when it’s worth repairing, based on its value.
Either way, verification happens before a unit is sold.
Load Bank Testing
Load bank testing runs a generator under electrical load to confirm it performs at its rated output.
WPP tests to 100 percent of rated output. A generator rated at 100 kW must produce 100 kW under load.
A standard test runs 20 to 30 minutes. Longer tests, including 2-hour or 4-hour runs, are available on request.
Voltage is confirmed as part of the same test, on the single voltage for standby units and across all voltages for portable and multi-voltage units.
Fuel-specific checks are also part of the same test. For diesel units, this may include checking for clogged filters while running. For natural gas units, testing is done on WPP’s in-house gas line.
Safety & Regulatory Compliance
NFPA 110 compliance applies mainly to the transfer switch and overall installation, not the generator alone. On the generator side, WPP checks the components tied to NFPA 110, including the battery charger and annunciators, before a unit ships.
WPP accounts for the codes and standards relevant to each application. Contact our team to confirm specific compliance or commissioning requirements for your project.
What You Receive as Proof of Testing
Each load bank test produces a test report documenting the load percentage and duration tested, whether a standard 20- to 30-minute run or a longer test built around project requirements.
What Sets WPP’s Process Apart
WPP retests every new unit after it arrives, even units already tested at the factory.
WPP has an in-house gas line to test natural gas units, and tests diesel units on-site as well.
WPP maintains a sizable technician team that services all major generator brands.
Generator Testing FAQs
Is a used generator tested the same way as a new one?
Not identically. If WPP already knows a unit’s history, that may stand in for a full retest. If not, technicians confirm start-up and load-holding capability before it is sold.
What happens if a unit fails testing?
Technicians diagnose the issue and repair the unit when it is worth repairing, based on its value.
What’s included in the test report I receive?
A test report showing the load percentage and duration tested, whether a standard run or a longer test built around project requirements.
Does testing add time to my delivery?
Testing is part of standard unit preparation, not a separate added step. Contact our team about scheduling for projects that require a longer or more specific test.
Does WPP supply distribution equipment?
Yes. WPP can supply transformers, island panels, distribution panels, transfer switches, and cabling alongside generation equipment — helping ensure both sides of the power plan are coordinated from the start.
Ready to Move Forward
Contact WPP to discuss testing details and availability for a specific unit.