Load banks are used to test electrical power sources like generators by applying an electrical load and dissipating the energy as heat. Resistive load banks test at 100% kW but only 80% kVA due to unity power factor. Inductive load banks allow 100% kVA testing by providing lagging power factor. Capacitive load banks provide leading power factor testing. Proper load bank selection considers voltage, frequency, capacity, installation location, and control methods to accurately test power sources.

1. LOAD BANK'S
IN CONSTRUCTIONS

2. WHAT IS LOAD BANK AND WHY WE ARE
USING THEM
• Load banks are used in commissioning , maintaining and verifying
electrical power sources in equipment's such as Generators,
Uninterruptable power supplies (UPS’s) and Power distribution Units
(PDU’s)..
• Load banks are used to apply electrical load to the power source and
dissipates the resulting electrical energy through resistive elements
as heat. Fans are used to cool down the resistive elements.
• Load banks are used to replicate , prove and verify the real life
demands on critical power system.

3. RESISTIVE LOAD BANKS
A resistive load banks are used to fully test the generators set at
100% nameplates KW rating. It will fully load the generator
cooling, fuel and exhaust systems. Only 80% of the generator set
nameplate kVA rating can be achieved when using load banks.
The resistive load bank will provide a unity or 1 power factor (PF)
load to the system under test.

4. INDUCTIVE LOAD BANKS
Inductive load banks are used in combination with a resistive
unit to provide lagging power factor load test. This mean the
generators can be test fully at 100% nameplate kVA rating.
Inductive load banks add inductance to the load and therefore
reduce the PF to less than unity (typically 0.8pf on diesel gen-
set).

5. CAPACITIVE LOAD BANKS
Capacitive load banks are used in conjunction with a resistive
unit to provide a leading power factor load test. They incorporate
industrial capacitors and increase the PF to above unity (leading).

6. RESISTIVE REACTIVE (COMBINED) LOAD
BANKS
Resistive reactive load banks usually consist of both resistive and
inductive elements that can be used to provide load testing at
non-unity PF (lagging) including the capability to test generators
fully at 100% nameplate kVA rating. They have single
construction witch can be independently switched to allow
resistive or inductive only or even varying lagging power factor
testing. .

7. SELECTION AND SIZING OF THE PROPER
LOAD BANK
• Assign the Proper Load Bank Type Based on the Type of the Application
• Assign the Load Bank Type Based on the Power Source Voltage and Frequency
• AC or DC voltage,
• Single or three phases,
• Voltage Rating. “The operating voltage of the load bank must match the voltage of the Generator or power source.”
• The operating voltage of the load bank must match the voltage of the Generator or power source.
• Single or multiple Voltages,
• Single or multiple Frequencies.
• Assign the Load Bank Type Based on the Power Source Capacity
• Calculate the Load Bank Capacity Based on the Power Source Capacity and Load Bank Type
• Assign the Required No. of Steps and Load Step Resolution
• Derate the Load Bank Capacity from item#5 In Case Of Testing Power Sources with Lower Voltage Rating Than That of
the Load Bank

8. SELECTION AND SIZING OF THE PROPER
LOAD BANK
• Derate the Load Bank Capacity Based on the Altitude and Ambient Temperature of the Installation Location
• Assign the Load Bank Type Based On the Available Installation Form
• Assign the Cooling Methods for Load Bank based on Load Bank Capacity and Space Limitations
• Natural Convection Air load bank type
• Integral Fan Forced Air load bank type
• Radiator Airflow load bank mounted on the generator set’s radiator
• Water Flow load bank
• Assign the Method of Control (Mechanical or Digital / Local or Remote/ Manual or Load Shed Control) For the Required
Load Bank
• Assign Blower Power Source (Internal Or External)
• Assign Enclosure Type for the Required Load Bank Based On Installation Location / Space Limitations
• Assign the Required Load and Supply Connectors
Load And Supply Connectors Type
• Cable Set (Cam-Lok plugs, lug style connectors or via bare braded wire ends) [Used with portable units]
• Terminal Block [Used with stationary and duct mounted units]
• Plugs (To match commercial wiring devices, aircraft plugs, MIL-SPEC plugs, cam-lock connections) [Used with Wide range of load bank application]

9. LOAD BANK CABLES
• For permanent Load banks regular THHN/THWN-2 OR THHW cables will be used.
• For temporary Load Banks the flexible cables are used since the cables are just laying around the ground. In the past
for larger loads diesel locomotive cable or DLO were used. This was an oil resistant rubber jacketed cable that was
very flexible. Cables like this have many, many very small strands that make up the conductor allowing it to be very
flexible. The issue was that DLO cable was not UL listed. In more recent times several manufacturers have come out
with UL listed Class G, H, I or K stranded cables such as XLPO from General Cable or X-Flex from Cobra Wire & Cable.
The user normally go to NEC table 310.15(B)(17) where they can find a #4/0 copper cable at 90C rated 405A. We are
mentioning #4/0 because this is a typical size maintained by the rental companies. This cable weighs 0.8 pounds per
foot - a 50 foot length weighs 40 lbs. (which can be moved on site by one person.)

10. REFERENCES:
• https://www.ascopower.com/us/en/resources/articles/load-
bank-basics.jsp
• http://www.electrical-knowhow.com/2020/04/how-to-select-
and-size-Load-Banks.html
• CEI Chief Technical Consulting Engineer - Rudy Bergthold, PE