Load Banks Direct Blog

For high power load testing of emergency power systems you can count on Load Banks Direct.

NFPA 110 Standards and Load Bank Testing

The National Fire Protection Association (NFPA) maintains several standards covering standby generators and the recommended load testing.

LBD manufactures Portable and Stationary load banks that are ideal for this periodic testing.

nfpa logoHere are the highlights with respect to load testing:

Site Testing of Generator Sets to NFPA 110:

NFPA 110 stipulates several different site tests which should be referred to in order to ensure compliance. Tests can be made at unity power factor, if the 0.8 power factor rated load testing of the complete unit was carried out by the manufacturer before shipment from the factory.

NFPA stipulates load to be applied for 2-hour full load test, with building load permitted to serve as part or all of the load, supplemented by a load bank of sufficient size to provide load equal to 100% of nameplate kW rating of EPS, less applicable derating factors for site conditions.

Maintenance and Operational Testing/Inspection:

All EPSS with ancillary equipment, including transfer switches, must be inspected weekly and exercised under load at least monthly, for a minimum of 30 minutes, preferably with load - not less than 30% of nameplate rating. If this not met, the set shall be exercised monthly with available EPSS load and annually, with supplemental loads at not less than 50% of EPS nameplate rating for 30 continuous minutes and not less than 75% for 1 hour continuous, for total of not less than 1.5 hours. NFPA 110 also requires circuit breakers be exercised annually with EPS in “off” position. Breakers rated in excess of 600 volts should be exercised every six months and tested every two years under simulated overload conditions

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Common Load Bank Configurations

Load Banks Direct (LBD) can provide a customized load-testing solution for just about any application.

We also have a broad range of industry-standard configurations to accommodate most common applications. Our standard configurations fall into 4 main categories: Portable, Stationary, Radiator Duct-Mounted, and Trailer-Mounted.

This brief introduction will help you determine which solution is right for you.

Permanent Solutions:

  • Stationary – These freestanding, outdoor-rated units are the most robust, high-capacity load banks available. These units boast intelligent operator controls, safety indication layouts, and adjustable load step resolution. They are the perfect solution for regularly-scheduled testing and commissioning of mission-critical standby emergency power systems.
  • Radiator Duct Mount – These units offer an easy to mount, cost-effective solution for providing diesel generators with a supplemental load that minimizes wet-stacking and improves engine emissions. They are equipped with intelligent safety circuits, indicators and operator controls, and their branch-circuit fusing virtually eliminates catastrophic failure.

Mobile Solutions:

  • Portable – These indoor-rated load banks are lighter in weight and they have caster wheels, so they can be moved from job site to job site or within your facility, but don’t let their compact design fool you. These units have the same intelligent operator controls, safety indication layouts, and adjustable load step resolution of the beefier stationary units.
  • Trailer – These rugged, “trailer-ready” units can be mounted onto your separately-purchased 7,000 or 10,000-pound GVW highway-rated trailer or we can supply them already mounted onto a DOT and ICC road-legal trailer. Our heavy-duty trailers feature a steel deck, dual axles, radial tires, electric brakes and lights, adjustable lunette eye, and front/rear stabilizer jacks.

For more information about our comprehensive line of UL listed, standard and custom-engineered load-testing solutions, please visit www.loadbanksdirect.com or contact our team of industry experts at 1-855-LBD-CALL or email us at This email address is being protected from spambots. You need JavaScript enabled to view it..

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Data Center Commissioning

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Data Center Commissioning is a critical step in the implementation of a new data center. 

It helps ensure the proper operation of the physical infrastructure systems and provides the highest level of reliability.

The process of commissioning validates the physical infrastructure design of systems including power, cooling, security, fire suppression, and management.


Data Center Commissioning with load banks ensures that key electrical and mechanical infrastructures are designed correctly so they perform accurately.

Portable load banks are used on the data center floor for PDU and hot/cold aisle testing. They are often used in large numbers and networked. Master control of load bank groups and advance features such as voltage scaling and kW Servo are major differentiators. LBD’s Series One digital controller handles these advanced testing features and more.

Trailer based load banks are often used to test large back-up generators and UPS systems. Important load bank features include data acquisition, remote control, and quick-connect Cam-Loks.

Integrated electrical and thermal testing with load banks targets: 

  • PDUs
  • UPSs
  • Generators & Switchgears
  • Cooling Systems – Chillers, Compressors & Air Handling Units

Benefits of load bank testing:

  • Allows for performance testing at design loadsnot normally possible until the data center is completely built out.
  • Thermal scanning is more effective at nameplate loads.
  • Allows for failover testing without putting live loads at risk.
  • Less unplanned downtime and fewer repairs.


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Types of Load Banks

There are three common types of load banks - resistive, inductive, and capacitive.

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A resistive load converts electrical energy to heat. Inductive and capacitive loads create reactance in an AC circuit.

A resistive load bank, by far the most common type, provides loading for both generators and prime movers.

The load elements resist current flow linearly and simulate unity power factor loads such as certain types of lighting and heating.

They generate heat which must be dissipated out of the load bank by means of forced air, convection or water cooling.

Resistance is measured in ohms and power is measured in watts. 

load banks 2

An inductive load resists changes in current and as such, when you examine the current, it lags behind the voltage.

Electromagnetic fields are the key to inductive loads, and as such all motors (fans, pumps, etc), solenoids, and relays are inductive in nature.

To accurately simulate these types of loads, inductive load banks are often specified.

Inductance is measured in Henrys.

Inductive loads have two types of power, real power and reactive power.

The real power is based on the work done by the device (such as what a motor is spinning). The reactive power is that which is drawn from the source to produce magnetic fields.

The total power consumed is real and reactive power combined, which is measured in VAR (volts-amps-reactive).

Typically, the inductive load will be rated at 75% that of the corresponding resistive load such that when applied together a resultant 0.8 power factor load is provided. 

load banks 3

Capacitive loads are for many purposes, the opposite of inductive loads.

They resist changes in voltage and the voltage lags the current (or more commonly said "current leads voltage").

Capacitance is measured in Farads. Like inductive loads, capacitive loads also have reactive power, but it's opposite the polarity of an inductive load. Therefore, a capacitive load has a negative VAR.

Capacitive load banks are not as common as resistive or resistive-inductive.

However, they can better simulate certain electronic or non-linear loads typical of telecommunications and computer systems and are used for precise testing of these associated power sources.

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Load Bank Defined

A load bank is a device to which power is delivered.

It is a component which develops an electrical load (i.e. consumes electrical power), applies the load to an electrical power source and converts or dissipates the power output of the source. Load banks are self-contained devices that include the load elements, controls and cooling systems necessary for operation.

In contrast, an actual building load or “real” load uses the power source’s energy output for some productive purpose, whereas the load bank uses the energy output to test, support or protect the power source.
When a load bank is used to test a power generating source by presenting an electrical load, the rated output capabilities of the power source can be verified before being put into actual use. This is critical for emergency power sources.

Load banks are fully controllable and provide a means of applying a predictable load. They often have incremental steps of load so that critical systems can be tested under varying conditions. The load bank is intended to accurately mimic the operational or “real” load which a power source will see in actual application.

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