Electrical?? Junction box installation question?

Question

Hi,
Please help me understand this electrical question. My electrician is running romex for an addition I am having done. He has it all meeting at a central location. I asked him about it, and he said that he was going to install a junction box there. Why does he not run the wires to the electrical panel? Is there any advantage to having a junction box? How is he going to get the individual circuits to be wired? Will he have to run seperate wires to the junction box? If this is the case, it seems it would be better to run the romex to the panel. Just tryng to understand..

Thanks for your time

pb4sc

Answer 1

First the wire going from the junction box (jbox) when he installs it is called the home run. And the rest of the wires are called branch circuits because they branch out from the junction box.

The reasons for using the junction box like he is doing are.
1. It keeps the breaker box from getting so full of wire that it looks like a rat nest and is a safety hazard. The NEC (National Electric Code) states that all work will be done in a neat professional manner.

2. By using a junction box when installing the circuit it makes the circuit easier to troubleshoot and repair later on if you have trouble with it.

3. It keeps the amount of wire run to a minimum so you don't have wires all over ever where which is a fire hazard.

4. by having less wires running to the breaker box it allows him to balance the load better.

5. by using the junction box it allows him to cut down on material used, and labor. Wire is expensive these days, and so is labor. Buying using less wire and less labor you are not going to be paying as much as if every wire was run to the breaker box individually.

As far as tieing the wires all together he will most likely use insulated wire nuts. There are also other methods, one is soldering the wires, one is using split bolt connectors, one is using crimp connectors.

From what you said in your question sounds like he is doing a neat professional job.

Answer 2

Electrical Junction Box Installation

Answer 3

Good question. All electricians do this. I'm guessing since it's an addition you are building, It would either be one or two circuits. If one room had 5 receptacles, all on the same circuit, it would be cost prohibited to run each one to the electrical panel. By putting them into a junction box, there only needs to be one Romex cable going to the panel. This cable will feed all of the other cables under the same circuit. Also, running all of the cables to the panel would be a real mess and you are only allowed up to two wires to a breaker.
This cuts down on a lot of expense of the extra cable, the extra time for the installation, the mess in the panel, and the possible code violations.
I would say that your electrician is doing the right thing.

Answer 4

Rather than run dozens of wires to the breaker box, I will many times use 12 or 14 gauge wire from the junction box to the switches & plugs, then run a single, heavier gauge, wire to the breaker panel.
It may be he will run 4 heavy wires to connect 16 smaller wires.
It keeps the breaker panel cleaner and requires less wire overall.
If you have 16 wires in the addition, and 50 feet to the breaker panel, it's going to take a LOT of wiring to get them all to the panel.

Answer 5

lets keep this simple here. as a master electrician, i only put in junction boxes when ABSOLUTLY necessary. the least amount of splices, the least amount of potential problems. if he is going to add another panel, it must be classified as a SUB-panel, and run with 4 wires, hot-hot-neutral-ground, with a seperate neutral bar isolated from the panel. if he is going to put in a junction box, yes--he will have to run seperate wires for each circuit, dont let him run one bigger wire!!!!!!!! that is not legal, and also a fire waiting to happen. good God man, be sure to have this work inspected by your local city inspector, or hire a licensed electrical contractor (who isnt his friend) to look it over. best of luck to you.

Answer 6

Wire cannot be pulled in more than 360 degrees of turns.
Normally you have to put junction boxes in at 270 at the most. Trying to pull even in 270 can end up stripping insulation off the wire in the raceway, then it shorts out.
Trying to pull it all out , if it scrapes is time consuming and expensive. All except the most simple of installs has junctions boxes, and in all my years, I never encountered a job that small. (but I guess they exist in theory)
But good thing you are learning.

Whooooops, this reference is commercial and your question is residential (romex, no conduit) . . . sorry, never did residential but I would guess to minimize clutter at the panel . . . also you do not pull your switch wires to the panel.

Answer 7

Maybe the current breaker box has run out of room for more breakers, and he's actually installing a new auxiliary breaker box for all your new circuits. But that means he would have to run a service entrance type main electrical line from your current electrical service at your main breaker box.

Answer 8

How far is the addition away?
Is he putting in another main panal?
Talk to him and ask him why then get back here and ask again.