Circuit Wiring for a Sub-Panel

By - Summary:

How to Install a Sub-Panel: Wiring for a Sub-Panel, Necessary Planning When Installing an Electrical Sub-Panel and the main feeder cable.

Installing a Sub-Panel

Electrical Question: I am installing a sub panel and have questions about the main wire connections.

  •  Can I connect the sub-panel wires by the Main lugs, or do I need to go into a breaker first.
  • Am I required to have only one separate ground rod?
  • I am planning on getting this inspected also.

Thanks for your time!

This Electrical Wiring Question came from: Katie, a Homeowner from Roy, Washington.

Additional Comments: Great resource for a homeowner.

Dave’s Reply:

Thanks for your electrical wiring question Katie.

How to Install a Sub-Panel

Application: Wiring a Sub Panel
Skill Level: Intermediate to Advanced – Best installed by a Licensed Electrical Contractor, Danger of Arc Flash.
Tools Required: Electricians pouch of hand tools and the various power tools necessary for installing the sub-panel.
Estimated Time: Depends on the type and size of the panel and available access to the project area.
Precaution: Any existing electrical wiring within the immediate area that may interfere with the installation of the sub panel should be identified and turned OFF and Tagged if necessary.
Notice: Installing additional electrical wiring and a sub-panel should be done according to local and national electrical codes with a permit and be inspected.

Installing a Electrical Sub-Panel and Planning the Circuits

  • Installing a sub-panel is something that requires careful consideration and understanding in order for the project to be done safely and according to a list of applicable electrical codes, this is why I recommend that homeowners consult a qualified licensed electrical contractor to assist with a project of this nature.
  • The main feeder cable wiring must be selected and sized properly and connected to a separate circuit breaker in the panel that is supplying the power to the sub-panel.
  • There are several factors that must be considered when sizing and installing a sub-panel and a qualified electrician will be extremely helpful to identify these with you.

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


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FAQs Frequently Asked Questions and Comments

2 Responses to “Circuit Wiring for a Sub-Panel”
  1. Dave Rongey says:

    Judy, I have photos of panels here on the website, however the best way to know if your alleged contractor did the work properly is to have the work inspected, and that would involve getting a permit for the work that is being done, as it should be.
    Do not allow your contractor to cut corners, an make sure you do not hire a sleeze, as you have said, but rather ask for credentials and referrals, otherwise you could be inviting problems.

  2. Judy Hickmann says:

    I am looking for a picture of a sub panel wired correctly to code for Washington State. I have a contractor who I believe did it incorrectly and want to have some knowledge of what is right for when he comes back. I think the guy is not up to par but I have to know more first. Thank you.


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