Eliminating J-Boxes?

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midget

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My mom and stepdad bought a new house a while back, and while they unpacking their stuff, they had me carrie some stuff to the shed...so I get out there and I notice the wiring is pretty hoakie looking, so I casually comment on how bad it is when I go back inside. :D

Oh yeah, my original question...lol...do you guys try to eliminate junction boxes whenever possible? Would there ever be a good reason to leave a j-box, even if it was possible to eliminate it?

Thanks guys! :D
 
Re: Eliminating J-Boxes?

Tear it all out and rewire to the current code. That's the safe route. When I look at a job and see what you are describing I either bring it up to current code or walk. For a contractor it becomes a liability problem. Not to mention that I prefer any job I am affiliated with is left in a safe, neat proffessional manner.
 
Re: Eliminating J-Boxes?

I told him I wanted to tear it all out, or the majority of it, at least...yeah, if it wasn't family I probably would walk away. Or just wait until he leaves for a business trip, rip it all out, and redo it all then. ;)

But about the lights dimming when some tools are used, wouldn't that happen even if I didn't pull power from the last receptacle to the switch? It's all the same circuit.

[ December 04, 2004, 05:01 PM: Message edited by: midget ]
 
Re: Eliminating J-Boxes?

Why not just rewire the thing and tell him
marry xmas.But take your time and do it code.
Don't forget about gfci receptacles

[ December 04, 2004, 05:08 PM: Message edited by: jimwalker ]
 
Re: Eliminating J-Boxes?

I told him origincally I just wanted to rip everything out, and start over...but he is like deadset against that for some reason. I have no clue why, though...*sigh* Everything I did I've done to Code, and I've cleaned up some other stuff...everytime I've met to put a GFI in there though, I either don't have tools with, or we don't have the receptacle...maybe I should just try to talk him into letting me redo the *whole* thing over Christmas Break. :)

Actually, my mom hired this electrician to come over to run some wire for the HVAC stuff...and I asked her to try to schedule it some day when I could get over there, so I could learn some more from his experience...so maybe I should just have him go out there and talk about how bad it is, and how it needs to be redone. :p

[ December 04, 2004, 07:13 PM: Message edited by: midget ]
 
Re: Eliminating J-Boxes?

As for lights dimming, heavy loads on long runs with multiple junctions & splices might tend to dim the lights a bit. If they dim considerably, then there is a problem which you can check with a voltmeter. I would think a 20A home run to the shop would suffice. You might see a momentary droop as a motor is switched on, but I think there would be no problem in the steady state.

When I switch on my bedroom TV, the bathroom lights, (on a dimmer), almost go out, but then they come back on. At my age, the lights aren't that important.
 
Re: Eliminating J-Boxes?

Yeah...the lights are gonna dim anyway...but I wasn't gonna get into it with him. :p

Say, though, that the lights did Dim and stayed dim...what kind of stuff would you check? Say you found there wasn't 120v present there...what would you look at next? What would you think would cause this?
 
Re: Eliminating J-Boxes?

If the lights dim, I would check first for undersized wire for the length of the run, then poor splices, or loose connections at daisy chained receptacles. Neighbor had a freezer quit working. Found a carbonized receptacle upstream in a daisy chain. Should have been a home run.

Sometimes, these add-ons are merely spliced onto an existing circuit for convenience. For a light load, this is OK, but for ACs and other heavy loads, not so good. You should estimate the max current that will be drawn. If that approaches the breaker rating, you should consider running a second circuit.

If there is exposed Romex, that is probably not allowed. I would think conduit or armored cable would be called for. Some cities won't allow BX though.
 
Re: Eliminating J-Boxes?

If there a table or something that you can use to figure out what size of wire you need for a long run?

Is there a definition of "Exposed"? I mean...it's ran threw the studs, no sheetrock, though...so would you consider that exposed? Doing it in FMC would be cool...but I doubt I could get him to pay for that. :p What's BX?
 
Re: Eliminating J-Boxes?

Midget, having not seen the wiring, I won't comment on what you should do, but there is a good chance that there is no violation just wiring that is not pleasing to look at.

NM can be run exposed, (see 334.10 and .12)

J boxes are not bad, and if the box in question is not in the way, there is no need to go to great pains to remove it.

As far as long runs, you would have to know the load (you can use the whole 20 amps if you wanted to) and do a voltage drop calculation.

Roger
 
Re: Eliminating J-Boxes?

Midget, I prefer to use Ohm's law to compute the drop. Wire resistance can be found in a number of handbooks. No. 12 for example carries a resistance of 1.6 Ohms/1000 ft. Then the drop at full load would be:

Vdrop = (1.6 Ohms/1000 ft)*2*L ft*20 A

The factor "2" is necessary because the total length of wire is twice the length of the run.

Then for a 100 foot run, the drop would be 6.4 volts.

Note that I have included the units in the equation. The feet should cancel out, and you are left with Ohms*Amps or R*I. Anything else would be wrong. This is why I stressed units earlier. One of the space shots was ruined because someone screwed up on units!

You can probably find wire tables on the Internet.
 
Re: Eliminating J-Boxes?

2KID / CM or 2RID / 1000

I like the equations written like that, they're easier for me to remember. K is a constant that they give you on tests and reviews, but the second equation is the one that Rattus used, moved around a little.

(2 x Resistance x Amps x Distance)/(1000)

Resistance can be found in the back of the NEC. If your shed isn't too far away from the house, I wouldn't sweat the voltage drop too much.
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I stopped by my dad's house one evening, and he wasn't home. I walked out to the enclosed side porch he was remodeling and discovered his junction box fiasco. I rewired it, eliminated his junction box, etc, and stopped by a couple of nights later to see what he thought. He was ticked! "If something goes wrong I won't know what you did!"
My reply: "Then call your electrician!!!" :D
 
Re: Eliminating J-Boxes?

Yeah, the shed isn't too far away from the house, in fact, it's like right next to it...I'm pretty sure the Home Run just comes right under the house, and into a j-box in the shed, although I haven't crawled under there to trace it out. But thanks for the quick lesson on Voltage Drop, nonetheless. If it was a long run of wire, though, I'd want to use a bigger wire to counteract the voltage drop, right? Is there an equation for deciding on wire size? Is there any other method to counteract voltage drop?

Alright, I'm a little confused about what it's OK to use a junction box for, and when you should just find some other way...because last year when we were learning resedential stuff, I went to fix something I did wrong, but I cut the wrong wire...so I asked my teacher if I could just put a j-box up there, instead if re-pulling a whole new wire...and he was like no, lol. It would have been in what would have been attic space, had it of been an actual house, so it would have been accessible. But you guys talk about if they are clean and neat work, it's OK. So how do I know when it's OK, and when I should find some other way to run the wire or whatever? Really, the only reason I want to take out the one in the shed is because it's only there because whoever did the wiring to begin with ran outta wire at that point, so it's only extending the wire which is feeding the switch. So I think it's pretty pointless, but I'm gonna leave it, since my stepdad didn't like the idea of taking it out. Oh well.
 
Re: Eliminating J-Boxes?

Is there an equation for deciding on wire size? Is there any other method to counteract voltage drop?
Click to expand...
That's the equation. The number it spits out is the volts lost under the conditions you specify in the equation. Then you take your starting volts divided by the volts at the end of the long run, and try to shoot for less than a 5% drop, give or take.

There's no hard and fast rule for junction boxes in the context you're in, IMO. (Obviously, junction boxes have to be accessible, as your teacher pointed out.) If you can see how to eliminate it, and it's important to you, feel free. But every painful once in a while, we have to put in junction boxes. It's not pretty, but sometimes, you gotta do what you gotta do.
 
Re: Eliminating J-Boxes?

What happens if someone burries one? How do you go about tracking it down? How do you learn all these eqquations and how to apply them? Is that the kind of stuff they teach you in the classes?
 
Re: Eliminating J-Boxes?

Midget, if you are well along in Algebra, you should have no problem with the Ohm's Law equation. Yes, they teach you that sort of thing in classes like DC Circuits, Electricity & Magnetism, etc. It helps also to understand the resistance per (1000) foot numbers found in the wire tables and to understand the way units and conversion factors are used. Eventually you will get to resistivity (Rho) of various materials which has the units of Ohm-centimeters.
 
Re: Eliminating J-Boxes?

Expensive, and not always entirely accurate. After a wall is drywalled, if you didn't pull the circuit yourself, grabbing the wire hound sometimes won't help! I try to get the plans, get the guy who pulled it--often they can remember exactly where it is.

In houses, using non-metallic boxes and romex, I just let the 6' & 12' rule guide me, and start groping the wall where I would have put the box. Usually I can stab it on the first or second try. :)

On this commercial job I've been on for a couple of days, we had the plans, had a hound, and the wall still ended up looking like swiss cheese! :D
 
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