66xxA, E435xB, 605xB, N3300A and E36xxA: 'Floating' the Output of a Power Supply Above Ground

The chassis of the power product must always be referenced to earth ground, for safety reasons. However, the output is isolated and may be connected to a point other than ground. It is most common for the output to be connected to circuit common, but in some applications it is advantageous to have the power supply output referenced to some voltage above (or below) ground.

For most Keysight Power Products, the maximum floating voltage is +/- 240 volts from chassis ground. However, the following products have different isolation voltages as indicated:

• 6015A/6035A: +/-550 volts
• 68xxA: 300 vrms
• 66312A: +/- 50 volts
• E3631A 6 volt output: +/-25 volts

Floating a power supply can represent a hazard to people and equipment. Be aware of the following considerations when floating a power product.

• Digital I/O ports are referenced to ground, regardless of where the power product output is referenced.
• A grounded analog programming source may short out the current sense resistor causing uncontrolled output currents or blown tracks on the power supply circuit board. Be sure the programming source is fully isolated. Think through all connections carefully.
• Multiple grounds in the system can cause ground loops resulting in extra noise, and possible dc measurement errors.

For more detailed information, click on the Power Products Catalog link for more information on these and other applications.