As always, consult the local authority having jurisdiction for any local electrical code rules that may be necessary in addition to the minimum requirements of the NEC. What Size Grounding Wire is Required for a 200 Amp Service You can use 8AWG (Copper) or 6 AWG (Aluminum) grounding wires for a 200-amp service. I hope this helps with you questions concerning sizing equipment grounding conductors for feeders.
The answer is based on NEC-2008, Sections 250.122, Table 250.122, and Chapter 9, Table 8 (conductor properties). The minimum size equipment grounding conductor for this 200-ampere feeder is a 4 AWG copper conductor. Required equipment grounding conductor = 6 AWG copper (Table 250.122 based on 200 ampere overcurrent protection for the feeder)Īccording to Table 8, a 4 AWG copper is required = 41,740 cm Copper-Clad Aluminum No-Te Eksarunchai/Shutterstock Copper-clad aluminum is your third option, and it provides some of the benefits of both previous options. The size of the ungrounded circuit conductors has been increased 149% therefore, the equipment grounding conductors must be increased 149% as well, per 250.122(B). The Short Answer: For a 200 amp service, you’ll need a 4/0 aluminum wire. This is done as follows using Table 8, chapter 9 of the NEC:Īdjusted size phase conductor ÷ Required phase conductor size = 250,000 ÷ 167,800 = 1.49 Now if the feeder ungrounded conductors have been increased in size from 3/0 copper to 250 kcmil copper (for example) for voltage drop reasons, then the required equipment grounding conductor must also be increased in size proportionately. The minimum size equipment grounding conductor required for a 200-ampere feeder is not less than 6 AWG copper (see 250.122 and Table 250. What is the minimum size equipment grounding conductor required for a feeder (400 feet in length) supplying a panelboard for charging equipment?įor a 200-ampere feeder, a 3/0 copper conductor is generally required by the minimum requirements of the NEC. I will answer the question without the voltage-drop calculation information since this information is missing.įirst, the question is restructured as follows: Note: if a voltage-drop calculation is performed for this 400-ft feeder, then the system voltage and phase configuration of the feeder are necessary for the voltage-drop calculation. The next bit of information needed is the size of the ungrounded phase conductors intended to be installed for this feeder. I presume you are referring to the size of the equipment grounding conductor with the feeder and not a bonding wire which is undefined by the NEC. The first item to clarify is the terminology. I will answer the question by inserting the minimum necessary information. The question appears to deal with a voltage-drop situation, but information is missing. For a 200-amp load center used for feeding charging equipment that is approximately 400 ft from main switchboard, what size of bonding wire is required? - T.
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