Large junction box:

Standard recessed lighting:

"Cuttler Hammer Residental Electrical Panel, 1960 vintage, with fuse cartridges as main instead of a circuit break as is most often used today"

11/15/2009 1:51 p.m.

Disclaimer: Many common DIY projects involve some electrical work. If you learn how to be safe, follow the laws, codes and ordinances in your area, and use a healthy dose of common sense, you can start completing these projects yourself.  Please read the full safety notice and disclaimer at the bottom of this post.

Good afternoon;

Some electrical projects can require the use of junction boxes.  Any electrical switch, outlet or fixture box that meet space requirements can serve as a junction box.  A dedicated junction box, one that has no switches or fixtures is often useful in certain situations.  These situations most frequently occur in existing homes that are being rewired.  When deciding where to make your connections and deciding if a junction box will be used you should consider several factors:

• Can I make sure of a existing switch or fixture box?  If there is one available, and accessible, this should be your first choice, as you don’t want to create unnecessary junction boxes.
• Can I put the junction box in a location that will remain accessible?  All junction boxes much remain permanently accessible.  This means that you must be able to access them without taking apart any part of the home or building.  You are not permitted to cover boxes with paneling or drywall.
• Is there any other reasonable way to accomplish this project without installing an additional junction box?  Is there some other outlet, switch or fixture on an available circuit you can connect to within a reasonable distance?

Reasonable is the keyword.  It is almost always possible to install your wiring in a manner that allows you to make all your connections in switch, outlet or fixture boxes.  When you rewire a old house this isn’t always practical, there are often outlets, fixtures, and switch boxes which have very limited access for rewiring.  There are times with it is a challenge to get just one new piece of cable down or up the wall to an existing box.  My personal opinion is that a properly setup junction box in an accessible location is a better choice than tearing open walls to allow installation of wiring to an existing box.  A junction box placed in the attic or basement can also be the easiest option in some cases where you need to add an additional outlet.  I encourage you to not over use junction boxes, as additional junction boxes will make future troubleshooting more complicated.

Junction boxes are also frequently required if part of the house is on a conduit system such as EMT and part of the house is on Romex.  EMT (metal conduit) is required to carry electrical wires in area that may be subject to physical damage (such as a unfinished basement).

In this video I will explain how connections are wired from a junction box that is making a transition from wires in a EMT conduit system to Romex.

Jamie Dolan
Neenah, WI

Always make sure the power is completely off prior to starting any electrical work. If your at all unsure that what your doing is safe and correct, then please do not attempt it and contact a licensed professional for assistance.  Despise some detail information being presented here (in writing & in video and or audio format), this tutorial is for education purposes only and is not intended to be a step by step instructional guide. Proceed with any project at your own risk, projects described here may carry the risk of serious injury or death.  Codes, laws and ordinances in your local area may vary from the ones discussed here. Please verify your local codes, laws, and ordinances prior to starting any electrical project.  Please ensure you obtain the permits as required by law or city ordinance. Proceed with any project at your own risk, safety and the final outcome of any project is the result of your skill level, we assume no liability for any project that you undertake.