This answer is taken from the CEC. Table 17 states minimum size of grounding conductors. For a service conductor drawing 400 amps a #3 copper grounding conductor is needed. Also see rules 10-206, 10-700 and 10-812 if you have access to the code book.
It is a safety measure for devices that have a metal case where a failure in the device could cause the case to be connected to the hot side of the circuit. By grounding the case the breaker will trip instead of you getting a shock.
Notes: 1. Where multiple sets of service-entrance conductors are used as permitted in Section 230-40, Exception No. 2, the equivalent size of the largest service-entrance conductor shall be determined by the largest sum of the areas of the corresponding conductors of each set. 2. Where there are no service-entrance conductors, the grounding electrode conductor size shall be determined by the equivalent size of the largest service-entrance conductor required for the load to be served. 1 This table also applies to the derived conductors of separately derived ac systems. 2 See installation restrictions in Section 250-64(a).
Minimum size grounding conductor for a 200 amp service entrance is #6 bare copper. The conductor connected to a metal water pipe, or whatever your primary grounding electrode is, is required to be #4 copper. This size requirement is often missed. The conductor connected to a ground rod is only required to be #6 regardless of the size of service. Typical installation is #6 bare solid copper.
300 Amps if used for service entrance conductors. Table 310.15
The grounding electrode conductor size chart provides information on the recommended size of the conductor based on the type of grounding electrode and the size of the service entrance conductor.
For an 800 amp service with parallel sets of 500 kcmil copper conductors, the grounding electrode conductor size should be based on the largest conductor in the parallel set. The grounding electrode conductor size should be sized based on Table 250.66 in the NEC, which recommends a minimum size of 3/0 AWG copper for 1/0 AWG or larger service-entrance conductors.
# A ground electrode conductor is a conductor that originates at the neutral or equipment ground buses in the main service entrance panel board or separating derived system (e.g. isolation transformer) # A ground electrode is a item that is in contact with the earth (e.g. Building metal frame, underground continuous metallic water pipe etc...) # A ground conductor is a conductor that is used to keep an electrical system continuous. Ground conductors are required, by code, in all PVC conduit runs. Ground conductors are also used to keep all metallic components of the installation at the same zero potential to overcome mechanical connections that would not carry a fault current back to the supply distribution panel.
This answer is taken from the CEC. Table 17 states minimum size of grounding conductors. For a service conductor drawing 400 amps a #3 copper grounding conductor is needed. Also see rules 10-206, 10-700 and 10-812 if you have access to the code book.
It is a safety measure for devices that have a metal case where a failure in the device could cause the case to be connected to the hot side of the circuit. By grounding the case the breaker will trip instead of you getting a shock.
In residential 120 VAC, single-phase electrical wiring, there are three main types of electrical wires: 1. Ungrounded conductor (Hot, and sometimes called "Line" or "Phase") 2. Grounded conductor (Neutral), and 3. Grounding conductor (Safety Ground or Protective Earth) The groundED conductor is the power return, intended as a current return path from the load back to the source to complete the "circuit." Its insulation is White, gray or a non-green color with white stripes. The National Electric Code requires it be connected to earth ("groundED ") at the service entrance and usually only there. The groundING conductor is usually the safety ground which serves as an emergency current return path in the event of a circuit fault or overvoltage. Like the groundED conductor, it too is grounded at the service entrance, but is also connected to metal surfaces and parts along the circuit, groundING them. It conducts current only if the current "seeks" to return to the service entrance along a path other than the Neutral (like through your chest, should a Hot wire becomes loose and contact metal in the circuit that you may touch). Since the grounding conductor doesn't normally carry current, its cross-section is sometimes smaller than the groundED conductor's. The grounding conductor's insulation is green (no other conductors can have green insulation) though sometimes it is bare copper. Sometimes the steel metal conduit enclosing the Hot and Neutral acts as the grounding conductor.
The clearance from a service entrance panel to grounding material should typically be at least 3 feet to ensure proper safety measures against electrical hazards. This distance helps prevent accidental contact and ensures effective grounding of the electrical system. It is important to adhere to local building codes and regulations which may specify specific clearance requirements for your area.
The required size of the service grounding conductor for a 350 amp parallel service will depend on the specific installation requirements and local codes. It is recommended to consult with a licensed electrician or engineer to determine the proper size based on factors such as the type of wiring used, the distance between the service entrance and the transformer, and the local ground conditions.
Notes: 1. Where multiple sets of service-entrance conductors are used as permitted in Section 230-40, Exception No. 2, the equivalent size of the largest service-entrance conductor shall be determined by the largest sum of the areas of the corresponding conductors of each set. 2. Where there are no service-entrance conductors, the grounding electrode conductor size shall be determined by the equivalent size of the largest service-entrance conductor required for the load to be served. 1 This table also applies to the derived conductors of separately derived ac systems. 2 See installation restrictions in Section 250-64(a).
A size 3/0 AWG copper main bonding jumper is typically required for service entrance conductors rated at 250 kcmil copper. This is based on NEC requirements for sizing the main bonding jumper to be at least 1/10th the circular mil area of the largest service entrance conductor.
Minimum size grounding conductor for a 200 amp service entrance is #6 bare copper. The conductor connected to a metal water pipe, or whatever your primary grounding electrode is, is required to be #4 copper. This size requirement is often missed. The conductor connected to a ground rod is only required to be #6 regardless of the size of service. Typical installation is #6 bare solid copper.
A grounding rod is a ground electrode installed into the earth and connected to the grounded neutral of the electrical system which in turn grounds the entire facility. It’s meant to keep the resistance low between the ground system and the earth. Grounding is an essential aspect of electrical systems that cannot be overlooked. A proper grounding rod protects against electrical shock and helps prevent equipment damage. How to Get the Most Out of Grounding Rods? Choose the Right Size The size of the grounding rod will determine its resistance to electrical flow, with larger rods offering better grounding than smaller ones. Proper Installation The rod should be installed vertically in the ground, with at least eight feet of the rod in contact with the soil. The top of the rod should be at ground level or below, and it should be driven into the ground using a driving tool. A bonding wire should be used to connect the grounding rod to the electrical panel or service entrance. Regular Inspection and Maintenance While most grounding rods are resistant to corrosion, regular inspection and maintenance are still necessary to ensure optimal performance.