How to Prevent an Electrical Floating Ground

Floating grounds are common in poorly designed systems.

A floating ground exist when the grounding point of a circuit is not at zero potential. For example, when you connect a line to ground, the voltage at the grounding point should be at zero volts. A floating ground exist when it is not at zero. Floating grounds occur primarily when cable shields are not grounded to the system ground. Cable shields exist between the outer insulation and the cable internal conductors. They exist to protect internal conductors from electromagnetic interference. However, if the cable shields are not properly grounded, they cause floating grounds.

Things You'll Need

• Grounding straps
• Soldering kit

Instructions

1. Identify all the cables in the circuit and determine if they have cable shielding. Cable shielding is the metal covering between the outer insulation and the inner connectors.

2. Replace the cables that have no cable shielding with shielded cables. Shielded cables of various sizes are available from most electronics and electrical hardware outlets.

3. Ground the shields of each cable to the system ground. To do it, peel back the insulation exposing the shield. Get a grounding strap and solder one end to the shielding. You can find grounding straps to match the size of the cable shield at any electrical equipment outlet. Attach the other end of the strap to an electrical ground for the system. An electrical ground can be an electrical equipment rack or a metal floor close to the cable. If you are not sure, refer to an electrical schematic of the system. Do this for all shielded cables.

References

• EP University:Grounding/Ground Loops
• AlphaWire: Understand Cable Shielding

Resources

• American Grounding Systems Inc: Grounding Straps