My new house has 2 wire ungrounded receptacles in most of the rooms. I want to upgrade to grounded "3 prong" receptacles.
Since removing the old (#14-2) AC wiring and replacing it is not an option I thought I could do it by running a bare #12 copper wire down to the crawlspace under the house, bussing all the wires together and ending at a earth ground spike and a cross tie to the main breaker box.
This should work but is it to code in California? DOes it need to be inspected? Is there any reason this would be unsafe? Should I use Insulated wire instead so the conductor never touches the structure (wood)?
I just wanted some assurance before I bust by butt under the house.
Do you mean "Type AC" AKA "BX". a spiral wrapped steel armored cable??? If so you already have a grounding path.
That is certainly an option although it might not be a california legal option. You can also skip the ground rod (assuming your existing panel is properly grounded). Install your bus and connect it to the grounding bus in the panel with a #4 or a #8 in a raceway. (#4 typically does not ned physical protection) The main issue I see is protecting everything from damage, environmental and physical. This is one of those cases where the increase in safety is worth a technical violation. It is probably a waste of time to upgrade the receptacles that will never see a
3 prong plug too. GFCI (the other way to install 3 prongs) is actually safer when you don't have a grounded case appliance.
4 gague wire!!! how much current do you think this ground path to see. I was planning to use 12 gague bare wire everywhere all the way up to the panel. Did I get you wrong?
GFCI gets me part of the way there but as you say it still does not offetr the same protection as a seperate ground on appliances so equipped.
The only reason I said 4 ga is an inspector would not require some kind of physical protection for #4. (based on the GEC rule) Actually a #6 Equipment Grounding Conductor can be run without physical protection. 250.120(c) when they are not in the wall cavity. In the cavity your #12 is OK. That is the main issue. You are right that for 15 and 20a circuits
12ga is fine based on ampacity. The only problem is, it is supposed to be protected in the jacket of your Romex. YMMV on how an inspector would feel about bare or green insulated #12s running around in the crawl space. Green insulated is probably what you are going to end up using since that is what they sell.. Usually #8 is the smallest "bare" you will find. Personally I wouldn't fail you if the #12 was neatly stapled and closely followed the floor joists. I would only worry about places where someone might grab it and break it.
Since your new add on Equipment Grounding Conductors (EGCs) will not be run with the circuit conductors the impedance of the fault current path will be much higher than if they were. I would suggest that you add Ground Fault Circuit Interrupter (GFCI) protection to the circuits in addition to the retrofit EGCs. That way when a fault occurs your retrofit EGC will carry enough current to trip the GFCI thus clearing the fault prior to contact by humans.
Can you put a number to "much higher"? I bet you would need a lab setup to see the difference. For the puropses of operating the branch circuit O/C device it should be OK.
First, external ground wires must be green insulated as, if I remember correctly, code demands that green insulation.
Second, ground receptacles to the single point safety ground located in breaker box panel. Receptacles provide a safety ground (not earth ground) which is why the ground wire must make a connection directly to the same bus bar used by white neutral wires (inside breaker box). This connection cannot be made indirectly via the ground rod. In fact, grounding directly to the ground rod would be a code violation.
Third, box must be earthed typically by a bare 6 AWG solid copper wire. This connection from breaker box to earth serves multiple purposes. Code only requires a breaker box be earthed to a nearby ground rod for human safety reasons. And code specifically demands a dedicated earth ground rod or equivalent. That earthing wire also must be less than 10 feet, with no sharp bends or splices, for another reasons beyond scope of the code - transistor safety.
Four, any circuit that cannot be safety grounded can provide human safety using a GFCI. A specific three word phrase must be printed on every three prong outlet that only uses GFCI for human protection. One reason is that some electrical equipment may not work correctly (and some interconnected electronics may be damaged) if the safety ground is not utilized.
Five, this and other grounding explained by volts500 in the newsgroup alt.home.repair entitled "Grounding Rod Info" on
12 July 2003 or at:
formatting link
So you think many outlets cannot be safety grounded? Be amazed how easily a good electrician can wire a safety ground without much damage. You pay them big bucks because they have those special tools and abilities.
.> First, external ground wires must be green insulated as, if
250.119 Identification of Equipment Grounding Conductors. Unless required elsewhere in this Code, equipment grounding conductors shall be permitted to be bare, covered, or insulated. Individually covered or insulated equipment grounding conductors shall have a continuous outer finish that is either green or green with one or more yellow stripes except as permitted in this section
The only place where whites and grounds can connect is in the service disconnect enclosure. That may NOT be the main breaker panel. You could have a service disconnect in the meter base or some other place outside. That is where the main bonding jumper is and the only place where grounds and neutrals can connect. You will still have a single point ground if this is true, even if you don't home run every grounding conductor. That is really only a surge protection issue, not a safety one. As long as you have a sufficient fault current path back to the main bonding jumper you will still trip a breaker on a fault. The NEC addresses parallel neutral paths but they don't care about ground loops on the EGC. You have them all over if you have a metal piping system. (water heaters, disposals, pumps, gas furnaces etc)
Green/yellow is a good choice if you can 'cause that seems to be universally used world-wide. (Well, outside of Italy where they do any darned thing they like. ;-)
You guys use *white* neutral wires? Blimey! I would get very confused.. Over here and in Europe it's either black or light blue!
A note for non-US readers: The above is applicable only in North America. Don't do this on an MEN system or you'll kill someone... ;-)
The only place we will see light blue neutrals is in line cords, mostly because they are sold internationally but even that sounds silly to me, since the only folks who use NEMA plugs are the US and Japan. I guess we blew up all the original Japanese plugs in 1945.
The green/yellow does seem pretty universal. The only other choice here is solid green or bare so it isn't that confusing. The only place you usually see bare wire is in a cable or in large sizes (3.7mm - 5.89mm dia) #8, 6, 4 AWG.
I guess we should all put a country in our taglines to avoid confusion. We don't even agree with Canada on a lot of things electrical. (politics or beer) I bet you even have round footballs ;-)
Red is hot here too. The one that will bite you is blue, that is a phase too here, typically phase C on a 208/240 3 phase. (except for those international line cords)
480 3 phase uses brown/orange/yellow.
The 277 L/N on a 480 wye will be violet phase and grey neutral. It was never really legal to use grey but everyone did it so they finally fixed the code.
I guess it is color codes that makes the electrical trade safe from foreign invasion.
Those boat guys have made up their own rules for centuries. That's probably why the NEC (NFPA) never wanted to have anything to do with them or vice versa. The NEC actually started as one page in the 1898(?) New York City fire code and now NYC doesn't even follow the NEC. There is a lot of politics in the NEC and a pretty good chunk of greed. It is a copyrighted document that sells for close to $100 in paperback. You won't see it published for free anywhere in spite of the fact that it has the force of law in most communities. Electrical professionals have a love/hate relationship with our code.
Actually I just had a Mike Holt class on grounding and bonding yesterday Dec 4. He mentioned NYC gave up their document and had just adopted the 1999 NEC within the last couple of months.
Gary Fiber Gary K8IZ Washington State Resident Registered Linux User # 312991
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