Rewiring and junction boxes

[jimbob]

I have been rewiring a dining room in a 1930's home. In new construction outlets are linked together by wires running horizontally through the studs. I haven't been able to find any guidelines for how to run wires when rewiring. The most logical way seems to be running wire through floor joists underneath the room in the unfinished basement. I have a couple of choices. I can run wire from outlet to outlet, passing the wire under the floor, or I can wire to junction boxes under each outelt with a wire extending to each outlet. The latter would allow me to use less wire and fewer holes through the joists. The first way would mean that I would use fewer junction boxes. Is there any advantage or disadvantage to either way? Anyone know of any guidlines for rewiring? Most of the info I have found is on wiring new construction.

Thanks

[Chris Lewis]

According to jimbob :

I've done the j-box approach myself. The feeds to each outlet box were AC armor, because it was thru a wall that was just lathe over masonry. Saved a fair bit in armor cable costs.

Inspectors don't like seeing lots of unnecessary J boxes. J boxes also may present some difficulties if you want to finish the basement.

An inspector probably wouldn't mind this.

However, for a single room you're unlikely to save enough money to notice. Indeed, the jbox approach may be more expensive. But quicker.

[Tim Fischer]

I don't understand the "fewer holes through the joists" point. From the first outlet, you'd run a wire down through the floor, through any necessary joists, to a point below the second outlet, where it would go up. You'd run a 2nd wire from that outlet back down, through any necessary joists (which shouldn't be the same ones as before) to the 3rd outlet, etc. The only "extra wire" is the doubled run between the floor joists and the outlet -- a few feet at most, which is insignficant in cost compared to junction boxes, covers, and wire nuts you'd need for the other approach. I also think this would be less labor intensive than the J-box approach, and more reliable (less connections = better).

-Tim

[glassartist]

Depending upon your city's building code... here there has to be access to j boxes. So whereever there is a jbox there is a cover. This, as mentioned by Chris, may be an issue if you wish to finish off the basement later. I would go with Tim's less is better. Be sure to check on the position for drilling your holes through your joists. I am not up on these codes but I think it is something like, no closer than two inches from the floor upstairs. So no one later nails through and hits your wire, but the center of the joist is better. That way if you enclose it later you can nail into the joist from the bottom and not hit the wire either.

What I would have done differently: In my old house I wish I would have made each improvement on its own circuit instead of connecting up to the old run. Older homes didn't use power the way we do. If you might use a coffee urn in the dining room and some other appliance that may draw a lot you may want to check out what else is on this old circuit. My coffee urn when hosting lunches can trip my breaker if the other outlets have a number of items plugged in, like Christmas lights or whatever. Good luck. ______________

KaCe

[jimbob]

You're right, it would be easier just running the extra cable. Screwing junction boxes into my ironwood floor joists and splicing all those connections is a real PITA and will cause all sorts of problems when I refinish the basement. I will have some work to redo, but I think it will be worth it. I will have wasted time and some wire. Oh well.

Thanks.

glassartist wrote:

[John Grabowski]

You may already know this, but receptacles in the dining room are required to be on a 20 amp circuit. Check article 210.52(B)(1)

[Steve Barker LT]

#1. It's the same amount of connections if you pigtail the outlet like you should. #2. It makes the work at the outlet a lot easier especially if you're using

12ga wire like you should be.

I say go with the J-Boxes.

[Tim Fischer]

I work with #12 almost exclusively -- it's not hard to use with the outlet boxes. I personaly don't see anything wrong with 'daisy chaining' using the outlet's screws -- frankly I think a screw connection is probably more reliable than a wire nut. But I realize not everyone thinks this way...

-Tim

[Steve Barker LT]

doing this is a #1 no no in some electricians eyes. You've created a series circuit so to speak and if that outlet were to go bad or come loose, then you loose the power downstream also. Pigtailing is the quality way of doing things.

[Tim Fischer]

I understand that a lot of people like pigtailing, but I don't see why a properly-installed screw terminal would come loose any more easily than a properly-installed pigtail...

Or maybe I'm just lazy . In any case, I've NEVER seen a pigtailed circuit done in a case where they could have just done a daisy-chain. Even the circuits that were installed by professional electricians.

-Tim

[Steve Barker LT]

That's because they take longer. Wouldn't want to take extra time to make it better when you can short cut and get away with it.

[Don Young]

Wirenut connections in a junction box are no "better" or reliable than terminal screw connections on an outlet. Nor does the junction box reduce the number of connections. If you count wire ends as connections, for the two power conductors the junction box method actually increases the number of wire ends from four to eight. If you count 3 wires in a wirenut as one connection both methods have four connections.

There are reasons to prefer pigtailing of the wires in an outlet box but the only reason to move the pigtails to a separate junction box is to reduce the number of cables to the outlet box. This can be a valid reason if the run is very long or difficult.

Well established trade practices are not established only because they are faster or cheaper, although that is a consideration. It is usually a pretty good idea to follow them (especially for novices) and using a separate junction box to feed every outlet is not normal practice with most electricians or in most areas. It is certainly not wrong or unsafe, and if someone feels that it somehow makes a job better and wants to do it, I see no problem with it. I would certainly ask my local inspector first, in case he does not like it.

Don Young

[jimbob]

After reading your responses it seems that there is nothing inherantly unsafe or wrong about using junction boxes. The problem seems to be creating inaccessible splices that could fail later on and be difficult to find. Also using a lot of j boxes can make a simple circuit unecessarely complicated and hard trace later on. It's just not neat work. Looking at the wiring I have done so far there are a few j boxes where the cable could have just as easily been spliced in the outlet box. Those will have to go. There is one j-box however that makes connecting a few outlets on a longer more difficult run much easier. This one will stay. In the future, I will try to avoid overuse iof j boxes and make sure if I do use them that they will be in areas that will stay accessible. Thanks for the help.

[Tim Fischer]

Just to be clear, inaccessible splices are a code vio. If you finish the basement, each of these j-boxes will need covers that will be visible (so as to be accessible) when the room is finished.

-Tim

[Chris Lewis]

According to Tim Fischer :

It's not just a matter of "like". Pigtailing grounds has been mandatory for a while, as have neutrals in most cases.

It's not a matter of safety of connection per-se, it's more a matter of safety during rework. Eg: if you pull a device for replacement (or abandoning it).

Pigtailing a ground means that even if you pull the device out, the ground is maintained thru to the rest of the circuit, even if you don't cut the hot.

Similarly, losing a neutral to downstream outlets can be bad.

Especially with shared neutral circuits.

[Chris Lewis]

According to Tim Fischer :

Accessible doesn't necessarily mean _visible_. Accessible means that it can be "got at" without removing permanent parts of the building.

A J box behind drywall is bad. A J box hidden by a wall mirror, or behind a removable panel etc is fine.

[We "hid" a Jbox behind a recessed lighting fixture that was held in place by its bezel. Pop the fixture, and the box is accessible. Perfectly acceptable.]

[Tim Fischer]

True. But he's gonna have a hard time hiding a box every 6-12 feet near ceiling level. I guess I'm picturing blank covers all over the place...

-Tim

[sylvan butler]

Yup.

How about one centrally located junction box (e.g. under center of floor) with wires out to each outlet in all directions (like a big ol' spider). Or perhaps one JB in the NW corner and one in the SE corner, each feeding two or three outlets on each adjacent wall.

Life isn't just all or nothing.

sdb

[Goedjn]

If you're gonna put J boxes up, you might as well stick outlets in them. Ceiling level outlet are occasionally handy.

>

[Mark Lloyd]

Yes, as are outlets at switch height. They don't get hidden behind things as easily as those close to the floor, and are easier to reach.