Nearly all electricians and electrical inspectors are familiar with the national electrical code requirement in sec.
Ground rod resistance tester.
The easiest way for you to measure the resistance of a ground rod is to use a clamp on ground tester.
Built to withstand an entire spectrum of ground testing methods fluke s family of earth ground testers have been designed to be accurate safe and easy to use.
Resistance should be less than 25 ohms if the system is connected properly.
The clamp ground tester is clamped around one of the electrodes and then measures the resistance of the entire loop.
P2 and c2 connect to a separate all metallic grounding point like a water pipe or building steel.
Aemc 6471 multi function ground resistance tester kit 500 ohms resistance 32v voltage 250 ma current by aemc 2 802 50 2 802.
Reads ground resistance down to 0 10 ω.
Molded carrying case 9v alkaline battery and calibration verification loop.
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With this method the resistance of two electrodes in a series is measured by connecting the p1 and c1 terminals to the ground electrode under test.
In practice for a residential structure most electricians place two ground rods and call it done.
250 54 which requires the resistance to ground of a single made electrode e g ground rod to be 25 ohms or less.
50 3 358 25 3 358.
If it is higher then you must place a second ground rod.
There is no requirement to retest the resistance.
Touch one lead to your test wire and the other lead to your test location for example an outlet s third ground plug which is the small round hole at the bottom of the outlet.
Using an earth electrode tester instead of a clamp on tester will take a lot more time and effort.
In areas where driving ground rods may be impractical the two point method can be used.
Unfortunately it seems many electrical professionals.
This type of tester is usually available at hardware and home improvement stores as well as from online retailers.
Fully auto ranging with data hold to capture readings.
This is a different tool from the clamp on multimeter which only reads ac current.
Measure grounding circuit performance without disrupting service.
The remaining ground electrodes are all in parallel and as a group are in series with the ground electrode being measured.
