causes of electrical fires??

[Master Brian]

Suba Dave, thanks for the link. Does that whole thing deal with residentual? I am glancing through it and it is a bit overwhelming. Most of that is stuff that I would never get into. It also looks like they do want Arch Faults in many other places besides the bedrooms, but the city's website doesn't say that. Maybe their code isn't there yet. Hmm....

Anyone take one of these homeowner tests? I am really curious how difficult it is.

Also, will they actually make me install a receptacle for the 6' rule on any wall space? Some rooms such as the bedrooms, I am working on making openings. However, my dining room already has wallpaper and I do not want it messed up. There are receptacles, just not per code. I didn't install them either. Remember this is a 1915 house.

[jar546]

The NEC has been in existence for over one hundred years and uses technical language, not layman's terms. This eliminates confusion.

It is not easy to read and not the easiest to understand unless you already have a firm grasp on the fundamentals of electricity and electrical work. The NEC is not a DIY manual. There are lots of books out there that are sold soley for the purpose of explaining parts of the NEC.

Almost every single chapter and section of the book has to do with residential in one way or another. You can probabl skep the 500 series section and some of the 700 section but you will find information that you need in every single part.

Here is an example:

A simple item like bonding or grounding the main panel is covered by multiple sections such as 250.50, 250.50(A), 250.52(A)(1), 250.66, 250.53, 250.53(A) & (D)(2), (E)(G)(F) and even more depending on other sections.

[Master Brian]

I understand it isn't meant to be easy for a layman.

I guess I am curious as to the test. The inspector didn't give me much info, just said, I can look at a copy of the NEC, there or at the library. Supposedly the homeowner test only covers the sections that pertain to residential, but like you say, every section seems to have residential stuff.

I can't however believe the stuff on bonding would be in there, as the homeowner isn't allowed to do the panel. *there being the test.

I do wonder how hard 25 questions in open book format with a 3hr time limit could be, but I have taken many 25 question tests in my field that easily take me 1 hour in open book format. So i'm willing to bet anything goes and I wonder how excited they are to actually have a homeowner pass the test. That is the Million Dollar Question!

I guess the only way to be sure is to take the test. Right now I am trying to draw up my plans and then I'll progress from there.

[jar546]

Here is an easy electrical question that a homeowner should know how to figure out as junction boxes are always being tapped into or installed. I recently came upon this situation while conducting a code inspection.

This may help to prime you for the test.

Basement, junction box. Metal 4" x 4" x 2-1/8" deep with cover and ground screw properly placed. No devices, internal clamps, plaster or extension rings on or in the box. Just wires and wire nuts except for the compression sleeve on the equipment grounds.

There were eight (8) 12/2 NMB cables entering the box.

Questions:

1) Is the box properly sized?

2) What is the box fill?

3) What size box needed?

[PeteD]

I can't resist taking a stab.

There were eight (8) 12/2 NMB cables entering the box.

Questions:

1) Is the box properly sized?
NO

2) What is the box fill?
17

3) What size box needed?
38.25 cu in - not sure of the standard size

Not an electrician so don't shoot me if I am wrong.

[Billy_Bob]

If you're going to get the NEC, Might want to get the NEC handbook which also has pictures and examples. Can get that here...
http://www.nfpa.org/catalog/product....ookie%5Ftest=1

And use that along with a residential wiring book which says it uses the 2008 NEC.

As to Arc Fault breakers, basically the 2008 says every room but those with GFCI. HOWEVER my state (Oregon) has modified the 2008 to be bedroom only. Also my state has exceptions for new GFCI rules.

Many people are having trouble with vacuum cleaners and a few other appliances tripping arc fault breakers. I would advise only installing Arc Fault breakers where required due to these problems.

Then other states are going by 2005 NEC rules or older. I think one island on Hawaii still goes by 1993 rules!

Anyway what is required is a local thing. The rules can even be different within a state (city different from rural), so find out what is required for your specific area and where you can get a copy of you areas modifications to the rules (if any).

This shows how different various states are with the NEC rules...
(The final word on this is your local inspector, not this map!)
http://www.nema.org/stds/fieldreps/N.../implement.cfm

[Master Brian]

This may help to prime you for the test.

Basement, junction box. Metal 4" x 4" x 2-1/8" deep with cover and ground screw properly placed. No devices, internal clamps, plaster or extension rings on or in the box. Just wires and wire nuts except for the compression sleeve on the equipment grounds.

There were eight (8) 12/2 NMB cables entering the box.

Questions:

1) Is the box properly sized?

2) What is the box fill?

3) What size box needed?

I'll start by giving my answer based off what I would do. I would say it is overfilled and I wouldn't put more than 4-5 wires max in that box. 4 is probably the most I would use and it would be a square box. I wouldn't know the fill and if I had the scenerio in front of me, I'd go by looks. I know that is not the "Correct" answer, but it should be safe.

Now if I were taking the test and having a posted 2008 NEC in front of me, here is my answer...

Is this a round box or a square box?

1) A 4x4x2-1/8 metal box (Round houses 9 conductors) (Square houses 13 conductors). So NO on both counts.

2) 18. The black and white wires account for 16, the ground wires account for 1. I am also adding 1 for the grounding clamp per 314.15(B)(2) of the NEC dealing with Clamp Fill states internal clamps should account for 1.

3) 4-11/16 x 2-1/8 square

[220/221]

what are the main things that cause an electrical fire?

There is only one thing that causes fire. Heat.

Heat usually comes from poor connection/terminations/splices.

Copper conducts electricity well. A loose connection builds up carbon where the electricity is jumping a gap. Carbon doesn't conduct well and the connection gets progressivly worse. In the right conditions the connection can get hot enough and act like a heating element to start a fire.

[Master Brian]

No response on the "Test"?

[GabeS]

No way you can put 8 cables in a skinny 4x4. This is just from common sense perspective and not code perspective.

A thick 4x4 would fit them, but it would be tight. And why in the world would you have 8 cables in a junction box anyway?

You would need a larger box than 4x4. I don't know what "fill" is.

[Master Brian]

No way you can put 8 cables in a skinny 4x4. This is just from common sense perspective and not code perspective.

A thick 4x4 would fit them, but it would be tight. And why in the world would you have 8 cables in a junction box anyway?

You would need a larger box than 4x4. I don't know what "fill" is.

I don't think of the 4x4 box mentioned in code as being "skinny", but I agree, I'd never put that many in either. May be deemed "safe" via code, but too hard to mess with in my opinion.

Fill, is referred to as the number of conductors. a 12/2 wire has 2 conductors + the ground. My understanding is all the grounds only count as 1 conductor, but I could be wrong. I didn't know what it was either until I looked through the NEC....

[Scuba_Dave]

Well with a 4x4 you could have 2 circuits or more
2 in, 2 out to the next box
Some people put a single gang triple switch - that's 3 wires to the devices. Say even 2 single gang double switches - that's 4 wires
I'd never do it, but I'm sure someone somewhere has

[PeteD]

Well with a 4x4 you could have 2 circuits or more
2 in, 2 out to the next box
Some people put a single gang triple switch - that's 3 wires to the devices. Say even 2 single gang double switches - that's 4 wires
I'd never do it, but I'm sure someone somewhere has

The wires don't really add up that quickly for combination switches, because you can run 3 wire cable. A deep 22.5 inch single gang box can handle a quad switch. One 14/2 coming in (2), two 14/3 going out (6), ground for all (1), and (2) for the switch. Total fill is 11, which works for 14 gauge (2 cu in per) with 0.5 inches to spare.

Pete

[Scuba_Dave]

The wires don't really add up that quickly for combination switches, because you can run 3 wire cable. A deep 22.5 inch single gang box can handle a quad switch. One 14/2 coming in (2), two 14/3 going out (6), ground for all (1), and (2) for the switch. Total fill is 11, which works for 14 gauge (2 cu in per) with 0.5 inches to spare.

Pete

Not if the lights are not in the same area
No reason to run 14-3 to an outside light, then to an overhead light, then to another light in another room, then to a light in a bathroom, then to another outside light on the other side of the house
And not if the runs are 12-2, which is what the "test" referred to
And yes I have seen that many switches in 1 place, but they used a 4 gang box for more room

[hj]

HOW does a circuit get overloaded if it has the proper sized wire for the circuit breaker?