Junction boxes - when to use them?

[Stephen Tashiro]

What determines where junction boxes are included in the plans for wiring a new house?

If it's desirable to have a continuous run of wire from the breaker box to an electrical device, then that's a reason for avoiding junction boxes. But I'd think that future modifications to wiring in a room would be easier if a junction box was handy.

[Wade Lippman]

Junction boxes are a sign of sloppy work. I suppose there might be a situation where future modifications are planned for, but you can almost always use an existing outlet or light fixture.

[Steve Rozmiarek]

Junction boxes have to be accessible, ie not covered by sheetrock. IMHO, that makes them look like poo. I've seen several dozen wiring failures from overloads of various causes in my line of work. I can't think of any that didn't fail at the connections, usually catastrophically. Think 200 amp 480 volt circuits turning into heaters unitentionally. Same thing happens on the smaller stuff, the connections are always the weak link. Minimize them.

[Jim Koepke]

What determines where junction boxes are included in the plans for wiring a new house?

If it's desirable to have a continuous run of wire from the breaker box to an electrical device, then that's a reason for avoiding junction boxes. But I'd think that future modifications to wiring in a room would be easier if a junction box was handy.

Planning a new house while consedering future modifications to the wiring is like paying a divorce attorney a retainer at your wedding reception.

The time to put in the wiring is when the house is planned and built. In some places added capacity can be planned and included in the build. Such places would be natural spots for an entertainment center, computer room and the kitchen for counter top appliances.

jtk

[Judson Green]

When I wired my shop (years ago and a commercial shop) I liked using j-boxes as I felt it allowed for the unforeseeable future, sometimes even a double deep with slack wire to aid in splicing. But if in a home I too feel that unnecessary j-boxes are a sign of sloppy work.

[Brian Elfert]

I agree with everyone who says to use continuous runs when wiring a house. I did have to use a junction box when rewiring my house this past Fall, but that was related to poor wiring by previous owners. The wiring in my house makes no sense as various parts of different rooms are on the same circuit. The lighting in one room and the outlets in another room are on the same circuit. At least the kitchen was wired to proper code for 1980 that already required a minimum of two 20 amp receptacle circuits.

If I had stripped the walls down to the studs I would have replaced the wiring in the entire house. As it is, my father and I replaced a large chunk of the wiring in the basement and on the interior walls. (The basement ceilings were torn out as part of the remodeling.)

[Ole Anderson]

I wouldn't intentionally include a j-box in a new home, but sometimes they are a necessity in a remodel. It is just too difficult to chase down the origin of some wiring behind the walls and above the ceiling without stripping them down to the studs.

[julian abram]

I am not an electrician although I play one from time to time. This is no excuse or reason to install a junction box in a new house under construction. I have build 13 houses over the years and would never allow an electrician to install a junction box in the wiring system, plus it's a violation of city code. Proper planning of lights, switches, wall outlets, appliances, etc. before construction and before sheet rock will eliminate any temptation of J-boxes being installed. However having said all that, there are some situations in remodeling that J-boxes are almost inevitable.

[Shawn Pixley]

I am not an electrician although I play one from time to time. This is no excuse or reason to install a junction box in a new house under construction. I have build 13 houses over the years and would never allow an electrician to install a junction box in the wiring system, plus it's a violation of city code. Proper planning of lights, switches, wall outlets, appliances, etc. before construction and before sheet rock will eliminate any temptation of J-boxes being installed. However having said all that, there are some situations in remodeling that J-boxes are almost inevitable.

I tend to agree with you except for one condition. When running wire in in conduit in a basement below the first floor joists, I have used pull boxes to address certain turning conditions. They have never been junctions, though my understanding is that they are treated the same under the electrical code. They are easy to remain accessable in open joist basements. For romex, I have never had to use a junction box in new construction.

[Robert Payne]

Okay guys, I'm confused by all of these "never install a junction box" answers. I purchased eight 4-bulb T-8 Troffer-style ceiling fixtures with pre-wired whips for my shop several years ago and wired them in two circuits, each with a pair of 3-way switches at the entry and exit points from each shop section. The schematic is shown below is the layout. Needless to say, I used two junction boxes in each room to attach the whips and the through wire for each circuit. Sure, I could have cut off all of the whips and run these without any j-boxes, but that wouldn't make sense. BTW, all of my outlet circuits are box-to-box per code.

I'll be interested in your responses.

[julian abram]

I tend to agree with you except for one condition. When running wire in in conduit in a basement below the first floor joists, I have used pull boxes to address certain turning conditions. They have never been junctions, though my understanding is that they are treated the same under the electrical code. They are easy to remain accessable in open joist basements. For romex, I have never had to use a junction box in new construction.

Shawn, I totally agree with you, no problem with accessible boxes in your basement. I would do the same.

[julian abram]

Okay guys, I'm confused by all of these "never install a junction box" answers. I purchased eight 4-bulb T-8 Troffer-style ceiling fixtures with pre-wired whips for my shop several years ago and wired them in two circuits, each with a pair of 3-way switches at the entry and exit points from each shop section. The schematic is shown below is the layout. Needless to say, I used two junction boxes in each room to attach the whips and the through wire for each circuit. Sure, I could have cut off all of the whips and run these without any j-boxes, but that wouldn't make sense. BTW, all of my outlet circuits are box-to-box per code.

I'll be interested in your responses.

No problem with j-boxes for your lights. The Opening thread asked "where to plan for junction boxes for new residential construction". Totally different application than adding lights in your shop.