Clamps & Current Measurement

Clamps & Current Measurement

Clamp meters are more versatile and flexible as diagnostic tools for electricians – while providing less resolution in its measurement than multimeters.

Essential check list for buying a clamp meter

• Minimum and maximum current levels
• Safety Installation Category Rating for your application
• Resolution and accuracy to accurately measure the minimum level of current
• Jaw size for access and maximum conductor size
• AC only current or AC and DC Current
• Ease of use, including features such as auto ranging, backlight and thumbwheel for function selection
• Any additional functionality including AC/DC Voltage, Resistance and Min/Max recording

Tips for measuring current

• For all general purpose applications excluding leakage current, clamp around a single current carrying conductor. This may mean splitting out the conductor for the rest of the cable.
• For low currents: multiplying the number of turns of the current carrying cable within the jaw will multiply the reading by the number of turns.
• Always try and keep the conductor in a central position in the jaw for the most accurate readings.
• Watch out for current carrying conductors outside the clamp meter jaw, but next to it. The magnetic field from current flowing in the external conductor can cause reading errors.
• Always make sure your clamp has the right safety category for the area of the installation you are working in.
• Use a True RMS current clamp meter to ensure accurate and repeatable measurements, particularly when troubleshooting overloads.