Help with grounding the house

[flboad]

Ok so my mom and boyfriend just bought a new house, it is an older Jubile style house.

It sits on a concrete slab (no basement) and the wireing is quite old. SO here's my problem there are no grounds in the house. The wireing is not romex.

Now for my question. How dangerous is it to keep it not ground?

OR would it be safe if i ran THHN around the house and from each outlet box that is on a wall faceing the outside i drill a hole through the wall and connect the box with copper to the THHN?

Now if that is doable would i be able to clamp the THHN to a copper pipe and drive it down into the ground. OR Would it be better to run it to the service panel's ground wire?


I know that this would only ground outlets that are on exterior walls but anything is better than nothing, right?

Any help would be appreicated, If there is a better or easier way that would be cool too.

[Sparks]

Would have to know what type of existing wiring the house has. Cloth wrapped, BX, aka armored cable.

[flboad]

at this point of the houses life it has mulitiple types. The older part of the house is a black caseing with a neutral wire (white) and hot (black). The newer addition and work i am doing is all 12 romex.

[Sparks]

First of all driving a rod or pipe into the ground and connecting the ground wire to it is not the way to go at all. This will not provide a safe electrical system whatsoever. Contrary to some opinions. I suggest you make a trip to your local library and read up on grounding and bonding. I don't mean this sarcastically. Running 10 or 12 awg thhn from box to box with either the proper grounding screws (not sheet metal screws) or with approved grounding clips is an option. Of course you would have to connect a jumper from each receptacle to their metal boxes or use receptacles that are self grounding via their mounting. Then you would connect to the service panel terminal block or the water pipe system (not plastic of course) with the proper connector clamp. You should also make certain that the water pipe system is properly bonded ensuring a good connection with the service ground. Another option for safety purposes would be to either use gfci circuit breakers or use gfci receptacles (one gfci receptacle can protect all other receptacles on that circuit). These are just options based on my opinion only and I would recommend consulting a local electrician in your area. Sometimes rewiring is not as hard as it appears. Residential electricians have a lot of tricks of the trade to pull wires that would amaze many homeowners. Good luck.

[Sparks]

A ground is not necessary for a gfci receptacle to work properly and sometimes this is the easiest way to protect receptacles that cannot be easily rewired. Just replace the first receptacle on the circuit with a gfci and all the receptacles on that circuit are protected. Just make sure you follow the directions regarding line side and load side!

[mjpliv]

Hey guys, we have ourselves an electrician answering questions. :D

[Rich]

Right on.. :)

[Vector]

Sparks is dead on. Read up about the subject. A lot of what appears to most people to be "common sense" is flat out wrong when it comes to grounding.

Sparks, correct me if I'm wrong, but I believe that running a separate ground wire, external to the existing NM cable is not code approved. I belive that flboad would be required to run new NM cables with a ground within the sheath to provide a true equipment ground to these outlets.

And the equipment grounds should always be run to the main disconnect (usually your main fuse/breaker panel) location. The water pipe should never be used as a conductor for ground, but rather as a grounding electrode with it's own connection to the service panel.

Also keep in mind that unless what you are plugging in has a three-prong outlet, you aren't using any ground. So if you aren't plugging anything in to a particular circuit that requires a ground, don't worry about it.

Change your bathroom and kitchen outlets to GFCI for certain. They won't require a ground as Sparks says, and you can do this anywhere else you need a three-prong outlet. The one exception is for certain equipment that absolutely needs a true equipment ground to function, such as surge supressors for computers. This can be addressed with a whole-house surge supressor, which is surprisingly cheap (under $200) and easy to install.

[Sparks]

Sorry for taking a while to reply. Obviously the best approach would be to rewire the house with romex but sometimes this is not in the budget. There are exceptions for this situation in the NEC. Article 250.130 states : For replacement of nongrounding receptacles with grounding receptacles and for branch circuits extensions only in EXISTING installations that do not have an equipment grounding conductor in the branch circuit, connections shall be permitted as indicated in 250.130(c). 1. Any accessible point on the grounding electrode system as described in 250.50 (which lists the water pipe) and 2. Any accessible point on the grounding conductor. Yes, going directly to the service panel IS the best approach. As far as running a separate conductor not enclosed in the romex see article 300.3-(2) Grounding and bonding conductors. Equipment grounding conductors SHALL BE PERMITTED to be installed OUTSIDE a raceway or CABLE ASSEMBLY where in accordance with the provisions of 250.130 (c) for EXISTING installations or in accordance with 250.134 (B). 250.134(B) states: Exception no 1: The equipment grounding conductor SHALL be permitted to be run SEPARATELY from the circuit conductors. This information is in the 2002 NEC or National Electric Code. There are exceptions that are used and most inspectors have to abide by the NEC. Again, these practices are not ideal, (we all would like to see all new romex and new euipment) but they allowed by the code for EXISTING installations only. As far as leaving the 2 prong receptacles on the premise that you can't plug anything but a 2 prong plug into them, what about those commonly used 3 prong adapters that are never connected with the screw as they should. These are used all the time in old houses. Again, opinions vary greatly on the subject of grounding and sometimes the best thing a homeowner can do is to hire a professional and have the work inspected hopefully ensuring a safe installation. Sorry about the long post but I could on and on about this subject, but don't worry, I won't. Nuff said I guess.

[Vector]

The length was great, and code references are always good. The exceptions are what trip people up the most :)

My pooint about leaving the 2-pron outlets was only if grounded appliances are not being used. If a homeoner is using "cheater plugs" then by all means they should either add the EGC, or GFCI protect the circuit.

However, when one looks at what actually requires the EGC, beyond computers and large appliances, most household electrical items don't use the EGC at all.

[Sparks]

I agree. But when there are 2 prong receptacles the adapters are often used even on major appliances. Old refrigerators have been responsible for many shocks over the years. When there is an internal short and the polarity has been reversed, possibly by just using the old 2 prong non-polarized receptacles with the cord end flip-flopped, a grounded modern receptacle would eliminate that potential by tripping the circuit breaker. As far as code is concerned, the exceptions are extremely useful in certain circumstances and should be noted when situations warrant.

[boilerette]

I have BX wiring in my house. There is a black wire, a white wire, and they are both encased in a pleated metal tube. This sounds like BX wiring to me and looks like the pictures of BX wiring I see.

My question is this:

I have 3-pronged outlets in my house that were here when I bought the place. I opened a couple of them up to look inside and noticed that there is no wire connected to the grouding screw on the receptical. Is this of concern for me? Or, does the whole receptical connect to the metal box which connects to the armor clad provide the safe ground?

Thanks,
Stacy

[Vector]

I have BX wiring in my house. There is a black wire, a white wire, and they are both encased in a pleated metal tube. This sounds like BX wiring to me and looks like the pictures of BX wiring I see.

My question is this:

I have 3-pronged outlets in my house that were here when I bought the place. I opened a couple of them up to look inside and noticed that there is no wire connected to the grouding screw on the receptical. Is this of concern for me? Or, does the whole receptical connect to the metal box which connects to the armor clad provide the safe ground?

Thanks,
Stacy

Your answer is:

Maybe.

The flexible conduit shell of BX wiring can provide a ground, provided that the connections are solid the entire way back to the panel. And the mechanical connection of the receptacle to the box can provide a ground path.

To find out, get a cheapie electrical tester from your favorite hardware store. Less than $10, maybe less than $5. They will tell you if there is a ground or not. This is the fastest way to check, and it's a tool worth having.

In my (current) house, we also have BX wiring, and some outlets have a good, working ground. Other have none, or a bad ground. In some cases, I've found loose conduit clamps on the cables, and reconnecting or tightening them has restored a solid ground. In others, nothing I've tried seems to work. Unfortunately, most of those are on the second floor, making them nearly impossible to do anything about.

For more in-depth testing, if you're comfortable working on your electrical system:

If it shows that there is a ground, you might want to double check the specific outlets to make sure nobody connected a wire from the neutral to the ground. The cheapie testers can't detect that, and a lot of people who don't understand grounding have done this over the years. And it's dangerous. It sounds like this isn't the case in your house, but you never know until you look.

If you want to find out how good the ground really is, turn off the main breaker in your house (so that there is no current on the neutral wires at all), then using an ohmmeter, test resistance between the neutral slot and the ground hole. The resistance should be very low, the closer to zero the better. I can't say at what point it becomes a "bad" ground, but I'd personally like to see something <10 Ohms, maybe 25 Ohms max.

Disclaimer: I am not a licensed electrician, electricity can be dangerous, proceed at your own risk, yada yada.