ask the electrician
Electrician Training Electrical Certification wiring recessed light fixtures Electrical Wiring Electrical Troubleshooting and Electrical Repairs wire outdoor light fixture Home Electrical Wiring Diagrams
wiring home generator and transfer switch wiring a 220 volt range cord outlet Wiring for GFCI Outlets Wiring Outlets and a Switched Outlet Wiring and Installing Ceiling Fans and Remote Controls wire dimmer switch wiring diagrams for switches wiring a dryer cord and 220 outlet circuit breaker panel
Electrical Wire and Cable

Installing a Sub Panel for a Detached Building

Do I need to run a ground wire for a 200 amp sub panel that is 200 feet away from the main panel? Grounding a Remote Sub Panel at a Detached Building.

Home Electrical Wiring Video

How to Wire a GFCI Outlet
without a Ground Wire

Check out my YouTube Channel and Subscribe to my Videos
» AskTheElectrician «

NOTE: A List of All my Helpful Videos
Will Display at the End of This Video
So Keep Watching So I Can Help You Wire it Right!

Grounding a Sub Panel at a Detached Building
Electrical Question #1: Do I need to run a ground wire for a 200 amp sub panel that is 200 feet away from the main panel?

This electrical wiring question came from Dennis, in Placereville, California.

Electrical Question #2:

What is the proper way to run an electrical supply to a sub panel in a barn or outbuilding?

This electrical wiring question came from Chris, a Handyman in Johns Creek, Georgia.

Dave’s Reply:
Thank you for your electrical wiring questions.

Grounding a Remote Sub Panel at a Detached Building

Application: Installing a Sub Panel for a Separate Building.
Skill Level: Advanced – Licensed Electrical Contractor – Not Recommended for Homeowners.
Tools Required: Electricians pouch of hand tools and the various power tools necessary for the specific method of electrical service installation.
Estimated Time: Depends on the type of panel, the location, and available access to the project area.
Precaution: This is an extensive project. Working in an electric panel has possible arc flash hazards and should be performed by a Licensed Electrical Contractor.
Notice: Installing an Electrical Service Panel must be done according to local and national electrical codes with a permit and be inspected.

Grounding a Sub Panel that is 200 Feet from the Main Panel

Electrical codes and information that should be considered when installing an electrical sub panel at a remote building.


The following terms are essential for this topic.
EGC – Equipment Grounding Conductor
This is the wire or conductor that serves as the connection to the ground.

Detached Building
Specific grounding and bonding rules apply to separate buildings (a detached building) or structures supplied by feeders or branch circuits.

National Electrical Code – The electrical codes that are generally adopted and applied to electrical wiring projects in the U.S.A.
Part III of the National Electrical Code (NEC) Article 250
This information applies to the requirements that are located in Part III of the National Electrical Code (NEC) Article 250, specifically article 250.32.

Conditions that affect Grounding a Sub Panel
The following are conditions that must be taken into consideration:


Specific grounding and bonding rules apply to separate buildings or structures supplied by a feeder(s) or branch circuit(s).
A grounding electrode is generally required at such buildings or structures, unless the building or structure is supplied by a single branch circuit and meets the requirements in the exception to 250.32(A).


More about Installing a Sub Panel

Electrical Code for EMT and PVC Conduit Fill

Guide to Home Electrical Wire

Electrical Wire for the Home

Complete listing of electrical wire types and parts used for home projects with electrical code information serves as selection guidelines.

Home Electrical Wiring Codes

Electrical Code Articles for Home Wiring

Electrical Code Directory covering basic electrical codes for grounding, panels and services, and underground wiring.

Circuit Breaker Panel
Electrician Explains Circuit Breaker Panels Complete with Photos. The home circuit breaker panel contains several circuit breakers that are carefully installed by experienced electricians and electrical contractors.

How to Install and Wire a Sub-Panel
How to Install and Wire a Sub-Panel – Photos and Explanation Describes the Right Way and the Wrong Way.

The following may also be helpful for you:

Dave's Guide to Home Electrical Wiring:

» You Can Avoid Costly Mistakes! «

Here's How to Do It:
Wire It Right with the help of my Illustrated Wiring Book

Great for any Home Wiring Project.
  electrical wiring  

Complete Guide to Home Electrical Wiring

Perfect for Homeowners, Students,
Handyman, Handy Women, and Electricians
Wiring GFCI Outlets
Wiring Home Electric Circuits
120 Volt and 240 Volt Outlet Circuits
Wiring Light Switches
Wiring 3-Wire and 4-Wire Electric Range
Wiring 3-Wire and 4-Wire Dryer Cord and Dryer Outlet
How to Troubleshoot and Repair Electrical Wiring
Wiring Methods for Upgrading Electrical Wiring
NEC Codes for Home Electrical Wiring
....and much more.

Learn more about Home Electrical Wiring
with my Online Video Course:
Basic Home Electrical Wiring by Example

Be Careful and Be Safe - Never Work on Energized Circuits!
Consult your Local Building Department about Permits and Inspections for all Electric Wiring Projects.

Electrical Tips to Help You Wire it Right

The Safest Way to Test Electrical Devices and Identify Electric Wires!

The Non-Contact Electrical Tester
This is a testing tool that I have had in my personal electrical tool pouch for years, and is the first test tool I grab to help identify electrical wiring. It is a Non-contact tester that I use to easily Detect Voltage in Cables, Cords, Circuit Breakers, Lighting Fixtures, Switches, Outlets and Wires. Simply insert the end of the tester into an outlet, lamp socket, or hold the end of the tester against the wire you wish to test. Very handy and easy to use.

The Quickest Way to Check for Faulty Electrical Wiring!

The Plug-In Outlet Tester
This is the first tool I grab to troubleshoot a problem with outlet circuit wiring. This popular tester is also used by most inspectors to test for power and check the polarity of circuit wiring.
It detects probable improper wiring conditions in standard 110-125 VAC outlets Provides 6 probable wiring conditions that are quick and easy to read for ultimate efficiency Lights indicate if wiring is correct and indicator light chart is included Tests standard 3-wire outlets UL Listed Light indicates if wiring is incorrect Very handy and easy to use.

Strip Off Wire Insulation without Nicking and Damaging the Electric Wire!

The Wire Stripper and Wire Cutter
My absolute favorite wire stripping tool that I have had in my personal electrical tool pouch for years, and this is the tool I use to safely strip electrical wires.
This handy tool has multiple uses:
The wire gauges are shown on the side of the tool so you know which slot to use for stripping insulation.
The end of the tool can be used to grip and bend wire which is handy for attaching wire onto the screw terminals of switches and outlets..

The wire stripper will work on both solid and stranded wire. This tool is Very Handy and Easy to Use.

More articles about Electrical Wiring, Grounding, NEC 250.5 Grounding and Bonding, panel, Sub-Panel and Home Electrical Wiring:
« Previous Next »
Add a GFCI Outlet Circuit to a Bathroom How to Fix a Sign Light Fixture