Use of junction boxes


  #1  
Old 07-19-03, 10:00 PM
hdsteele
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Use of junction boxes

Hi all:
I have an old house with a garage ceiling that looks like a spider web due to all of the wiring and rewiring done over the years. I would like to clean it up but to do so I would have to extend the length of both 110 and 220 cables going to various places in the house. Is it ok to cut and extend these cables by putting in junction boxes at the ends of the old cable and insert new cable between? Does it hurt the electrical system in anyway? I believe the cables are 12/2 and 14/3. Can larger cable such as 6 or 8 gauge be lengthened by use of junction boxes?

Any comments appreciated!
 
  #2  
Old 07-20-03, 08:14 AM
J
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If it ain't broke, ...

If the only reason you are doing this is to "clean it up," then I recommend that you leave it alone.

Tell us more about your motivations.

P.S. The direct answer to your questions is that yes, you can extend all of these by splices in permanently accessible junction boxes. But there are probably a million ways to screw this job up if you don't know exactly what you are doing. So make sure you use the right cable, the right boxes, the right staples, the right connectors, the right box packing, the right techniques, the right cable protection, and strip the right amount of sheathing and the right amount of insulation without nicking the wires.
 
  #3  
Old 07-20-03, 09:24 PM
hdsteele
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Depends on your definition of broke...

If "ain't broke" means it all works I guess it "aint". However, the last "licensed electrician" (have his 1973 card in the records we inherited when we purchased the home last year) seemed to feel that the following were OK:

Open junction boxes behind drywall and plaster
Running 240v with no conduit through gaps chisled in the brick above a door going from garage to unfinished basement to the service panel and then filling the gaps with plaster to close off
Splices in cable behind closed walls with NO junction box
Cable run with no conduit through a very sharp hole cut in a steel I-beam
Cable laying directly on water pipes, etc. etc.

My motivation? Make my garage look like it wasnt a first semester project for the local Vo-Tech and being able to sleep at night!!! Cables run directly on the garage ceiling criss-cross each other following no real plan except to get to the next joist where (maybe) it is tacked down with oddly enough the right size staple or bracket. Yes, it does all work because the guy knew how to connect things properly but it would be hard to make it less safe or give a more unprofessional appearance.

I am far from being an electrician but can strip wire, understand 3 and 4 way switches and know when to stop twisting the wire nut. I own and know how to use a multi as well as continuity tester. First thing I did was map my circuits because though there havent been any tripping problems I had no faith that I wasnt at least borderline on some. My plan is to re-run new cable, 12/2 for 20 amp 14/2 for 15 amp in a neat orderly fashion with junction boxes with covers and conduit where it seems reasonable (like over the bare brick and sharp steel openings so it doesnt rub raw over time). Run more cable to put the microwave, refrigerator and range on their own circuit as as they should be and connect the receptacles and several dimmer switches. Then I'll call in a licensed guy to go over what I did and make the connections to the service panel even though there is plenty of space/open breakers, the service (200 amp) is adequate and within my D-I-Y reach.

With things electrical I am, above all else, CAUTIOUS (which led me to asking my question). Obviously, no junction boxes are better than having them. As a matter of fact, went out today and purchased all new 6 gauge for the range because a junction box on 240v just seemed wrong to me given a choice.

Yes, I guess there are a million ways to screw it up but I don't see this as out of the scope of a do-it-yourself.com project given a reasonable amount of knowledge and help from the good folks in here!
 
  #4  
Old 07-21-03, 06:33 AM
J
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Yes, you should correct all of the things you listed. And yes, this is a reasonable job for a skilled and careful DIYer.

Before starting, make sure you understand these concepts which commonly trip up DIYers:
  • Know what 2-way and 3-way switch loops are, and how to recognize one and how to properly wire one. Understand other cases too in which a white wire is not a neutral.
  • Know what a multiwire circuit is, and understand why the two hot wires must be on separate legs of the power.
  • Know what a split-wired receptacle is, and understand the purpose of the tab on the sides of a receptacle.
  • Understand the wiring differences between a pure 240 appliance, such as a water heater, and a 240/120 appliance such as a clothes dryer.
  • Understand what a GFCI is, when to use it, how it works, and how to properly wire it.
  • Get a copy of the inexpensive book "Wiring Simplified". This book explains the code issues that a DIYer commonly encounters.
  • Understand the difference between equipment grounding and service grounding. These two systems are completely different in purpose.
  • Understand why you cannot connect a neutral to a ground outside the main panel, and why you cannot connect a grounding wire to a plumbing pipe.
Good luck.

If you search this forum, you can find lots of information on all of the above points.

By the way, there's nothing wrong with a junction box on a 240-volt circuit. A 240-volt circuit is pretty much like a 120-volt circuit except for the voltage.
 
  #5  
Old 07-21-03, 09:18 AM
P
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Instead of numerous junction-boxes of different sizes for different size cables, consider a sub-panel at a "strategic" location. 3 feeder conductors in one cable can re-place 30 conductors in 15 cables. If you connect 100 amp conductors safely protected by a 100 amp CB you can use a sub-panel with any number of breaker-positions up to 42 maximum.

This is a very tedious assignment, but I suggest that you first make an accurate table that lists exactly what outlets are connected to each breaker.The sub-panel will provide space for additional circuits should you determine that existing circuit should be relieved of an excessive number of outlets. You may find that one circuit has 15 or more outlets and another only 3.------------- Good Luck!!!!
 
 

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