How many wires in one junction box?

[Christopher Nelson]

I'm getting ready to put in some recessed lighting. I'll have six lights in a rectangular room: one on each short end and two on each long side. The access above makes it easiest to run all the wires across the room above the ceiling to one long side and hook up the switch in one corner. Something like:

S

| || || | O| O| | | | | | | | | | O | | O | | | | O O

(That's clear in a fixed-width font.)

My question/problem is, how many wires can I put in one junction box? The most natural arrangement with a minimum of boxes seems to be to get three lights to one junction box, three to another, then take a lead from each of those to another to connect to the switch. With a big enough box, is this OK? I can't imagine a wire nut big enough for four leads. Do I have to do 2 and a jumper, 2 more and a jumper, then the two jumpers together? For four grounded wires, that's a lot of wire nuts in one box.

[jamesgangnc]

Typically the wiring for mutiple lights is daisy chained from light to light and then from the last light to the box.

And you can get wire nuts that will hold more than 4 wires easily.

[DT]

When you buy the wire nuts, the number and sizes of wires it will handle are listed right on the box. Like:

4 #12

3 #12 + 2 #14

2 #12 + 3 #14

5 #14

etc.

[Steve B]

What you are asking is to be determined by how many switches you want to be able to turn the lights on and off from.

Like in a hall. You have one light, and you only want one switch. But if you have one light, or more, and want a switch at both ends of the hall so you can turn it off from either end of the hall, you will have more wires.

There is a new thing that is a variation on a wire nut. It is half clear plastic and half colored plastic. It has various amounts of holes in it, and you strip the wire off about 1/4", and stick the end in one of the holes. There is a barb in there that seizes the wire and holds it. I was brought a bunch by a union electrician friend of mine, and we used them on some of my lighting, and they work great, as they allow you a little more space in the box, and you can line up the wires making things more visible, and they lay better.

Check them out. They may be an alternative.

Steve

Heart surgery pending? Read up and prepare. Learn how to care for a friend.

[trader4]

The number of wires allowed in one box is given in the NEC (for the USA) and depends on the volume of the box and the gauge of the wires. However, for the light job, as James already answered, it's usually not an issue because there is enough volume in the recessed fixture to allow one romex in, one out and you daisy chain them.

[The Daring Dufas]

I am very fond of the push on wire connectors produced by several manufacturers.

The connectors allow for more wires to fit in a box and more room in the box.

TDD

[bud--]

I don't see how they allow more wires to fit or save space.

And I wonder, as Smitty did, if they will have the reliability of backstabs. They may be a good product.

[dpb]

bud-- wrote: ...

...

Au contraire...

Code allows a specific volume fill based on number of conductors in a given box size...

--

[The Daring Dufas]

There are times when even the max allowed wires won't fit in a box when you're using wire nuts or when you make a little change and the darn box is too tight and a customer doesn't want to pay for a whole freaking rewire job. It happens, all electricians pack more wires in a box than allowed every now and then.

TDD

[RBM]

This type of connector comes standard in Halo recessed fixture splice boxes. They have it attached to tinned stranded conductors. I was very skeptical about their reliability at first, but having used them on literally hundreds of fixtures at this point, I'm a believer. The only failures I've had, are where the tinned, stranded fixture wires weren't installed properly at the factory, and slipped out. I've never had a failure on the solid conductors.

>

[The Daring Dufas]

The best connectors I've seen and used for light fixtures are made by Wago, the connectors make changes and ballast replacements easy.

TDD

[RBM]

Very nice, but looks expensive

[Steve B]

>>>> >>>>

There's always the alternative. Go as cheap as you can and hope that it will last until you sell the house.

Steve

[RBM]

>>>>> >>>>>

The alternative is a standard wire nut, they're cheap and I've never had a problem with them. The real advantage to this wago type is that the wires aren't all twisted together tightly, which is messy when you need to undo them

[The Daring Dufas]

>>>>>> >>>>>>

I've been using the Ideal two hole push on connector for ballast changes in commercial environments for years and have yet to have one fail. You can even remove the wire and reuse them reliably.

TDD

[Steve Barker]

those look cool. I'll bet they're good and cheap.

[Steve B]

>>>>

The ones I have are cuboidal, transparent, and have a reverse barb to hold the wire in it. You just push the slightly stripped wire in it. Like switches and receptacles, there is a place to insert an icepick and take the tension off the wedge holding the wire in, making them reusable.

Sometimes, with a wire nut, particularly when joining four of five wires, you end up with a big wire nut. Put two, three, four, or five in a junction box, and you don't have much room left.

Steve

Heart surgery pending? Read up and prepare. Learn how to care for a friend.

[bud--]

I would expect a connector that has a lever to lock the connection would be reliable.

For commercial and industrial fluorescent ballasts you generally need a disconnect, which can be done with another Wago product:

't think the one above would qualify as a disconnect.