If the load is 380 amps or less, then you can use a 500 MCM. If the load is 381 amps or higher, you cannot use a 500 MCM. If you have not calculated the load, and you plan to use a 400 amp overcurrent device to protect a 400 amp panel, then a 500 MCM will not be sufficient.

Related Resources

Wire Size and Amp Ratings

4 grounding electrode

Proper Grounding Rod In most cases, pipe or rebar can be used. The grounding rod needs to be made of galvanized steel and also needs to be at least four feet in length for best results.

Suppose you drive the first ground rod for a system. If it has a ground resistance of 25 ohms or more, 250.56 of the 2005 NEC requires you to drive a second rod. Ground rods spaced less than two rod-lengths apart will interfere with each other because their effective resistance areas will overlap (Fig.

Bare naked ground conductor is perfect fine in certain space. The reason the CODE requires the ground conductor to be inside the conduit is for protecting the conductor from being damaged by any mechanical means e.g., gardener weed whacker. In fact, you can use PVC to house the ground conductor.

A fundamental component of safety and protection for your business and/or home’s electrical system is proper grounding. For this reason, one or more ground rods are required on your property by the National Electrical Code (NEC) and local building codes.

8 feet

Get an old bumper jack and attach a chain to it and the grounding rod. Then just use the jack to lift it out. That’ll work or if there is enough of the rod above the ground use a large pipe wrench with a hydraulic bottle jack under it. The pipe wrench will lock around the pipe and not slip like a chain usually does.

If the facility being grounded has a life expectancy of less than 15 years, a galvanized ground rod is appropriate and will provide the most cost-effective solution. For installations with a longer service life, copper-bonded ground rods are the best fit.

(A) Accessibility. All mechanical elements used to terminate a grounding electrode conductor or bonding jumper to a grounding electrode shall be accessible. Exception No. 1: An encased or buried connection to a concrete-encased, driven, or buried grounding electrode shall not be required to be accessible.

Is it possible to have TOO MANY ground rods that creates problems?? No Bob you can put in as many as you can afford, but there is a point where it does no good. For simplicity follow this rule for ground rods spacing should be equal to the length of the rod. So if you are using 8 foot rods space them at 8 feet.

Household electrical systems are required by the National Electrical Code (NEC) to have a grounded system connected to earth ground via a ground rod. The Ground Rod is usually located very close to your main electrical service panel. Since 1990 it has been general practice to install two ground rods for safety.

The major indication of a grounded home is three prong outlets instead of two. A three-prong outlet usually has a “U-shaped slot” which serves as the grounding component in the outlet.

8′ ground rods cost about $11 apiece – 10′ if required in your area about $15 each. The grounding wire, assuming #4 bare copper wire, about $1.20/LF, 4 clamps at $5 ea – so assuming about 10′ run to each rod, then about $66-74 materials – say maybe $80-90 with markup.

To ensure your home is safe, you should always test your ground rod resistance. You can do this at home using a multimeter.It is a handheld testing tool that is mostly used to take voltage readings. Advanced digital multimeters can take ampere and ohms (resistance) readings.

5.0 ohms

Check the resistance reading on the meter. Your clamp-on ground tester will have a screen that will show you a numeric reading. The lower the number on the meter, the better your grounding rod is working. In general, a reading under 25 ohms means that your ground rod has a good connection to the earth.

Ground Testing Techniques

1. Soil Resistivity Test. This is the most commonly used method used for testing newly-installed grounding systems.
2. Fall-of-Potential. The fall-of-potential method is typically used for testing individual grounding stakes or grounding systems as a whole.
3. Stakeless.
4. Selective.

Step 2 – Install the Ground Rod Horizontally If you hit a rock trench before you can hammer the rod down all eight feet, then you can simply install it horizontally. Shovel out a strip of the earth at least 2 1/2 feet deep and long enough to accommodate the entire grounding rod (at least 8 feet).

The only legal ground rod must be installed a minimum of 8-foot in the ground. The length of rod and pipe electrodes is located at 250.52(A)(5) in the 2017 National Electric Code (NEC).

The requirement is 2 rods spaced at least six feet apart unless you can prove one rod will turn less than 25 ohms resistance. That is all the requirement is. Run all the extras you want, the requirement for rods is two unless there is less than 25 ohms on one rod.