Fluke 124 — guidelines for Proper Grounding in Electrical Measurements [67/86]

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Tips and Troubleshooting

Using Proper Grounding

Incorrect grounding can cause various problems. This

Section gives you guidelines for proper grounding.

 Use the short ground lead(s) when measuring DC or

AC signals on input A and input B. (See Figure 3-2.)

Warning

To avoid electrical shock or fire, use only one

COM (common) connection

, or ensure that

all connections to COM

are at the same

potential.

 Use the unshielded black ground lead to COM

(common) for Ohm (Ω), Continuity, Diode, and

Capacitance measurements. (See Figure 3-3.)

Using the unshielded ground lead is also possible for

single or dual input measurements for waveforms with

a frequency up to 1 MHz. This may add some hum or

noise to the waveform display due to the unshielded

ground lead.

Figure 3-2. Grounding with Short Ground Lead

Figure 3-3. Grounding with Unshielded Ground Lead