Grounding

[nobertos]

I need to upgrade my home electricity - I have a home built in 1946. I don't have any grounded outlets, and most all are only 2 prong.

What are my options? Do I have to put a ground rod in (sounds hard)?

I'd like to have all 3 prong grounded outlets.

-c

 

[Toller]

Your electrical system has to be grounded already. If it isn't, you have worse problems than not having grounded outlets.

Why do you want a ground?
Have you checked to see if a ground is available at the outlet, perhaps via grounded conduit?

 

[w_tom]

First decide what your objective is. For example, wall receptacles are grounded firstmost for human safety. That safety grounding also accomplishes other lesser functions. But other, less expensive methods can provide same human safety. Earthing the electric panel is both for human safety AND for transistor safety. This being different from grounding of wall receptacles. And there is no alternative to earthing.

Converting all wall receptacles to 3 wire is a massive
undertaking - typically rewiring the house. Earthing the breaker box is a minor job that should be installed everywhere. Those are two different types of grounding. Both are part of a human safety system. And both also have different functions. First define your strategic objectives. Then your question can be better answered. Why are you grounding? What problems, current and future, do you want to solve?

It is probably a good idea to consider three wire outlets in the kitchen since 1946 kitchen wire is, by today's standards, undersized. But again, first you must define the problem to be solved.

 

[Matt (archive)]

Get some quotes, get the money, and let an electrician do the work.

 

[Bob Vaughan]

Your electrical system has to be grounded already. If it isn't, you have worse problems than not having grounded outlets.

Why do you want a ground?
Have you checked to see if a ground is available at the outlet, perhaps via grounded conduit?

If the house was built in 1946, there is a possibility that the service was not grounded..

The house that I am renting was built during that time, and did not have a grounded service until the service entrance was replaced last year when rain gutters were added following a roof replacement.

 

[Jeff Wisnia]

First decide what your objective is. For example, wall receptacles are grounded firstmost for human safety. That safety grounding also accomplishes other lesser functions. But other, less expensive methods can provide same human safety. Earthing the electric panel is both for human safety AND for transistor safety. This being different from grounding of wall receptacles. And there is no alternative to earthing.

Converting all wall receptacles to 3 wire is a massive
undertaking - typically rewiring the house. Earthing the breaker box is a minor job that should be installed everywhere. Those are two different types of grounding. Both are part of a human safety system. And both also have different functions. First define your strategic objectives. Then your question can be better answered. Why are you grounding? What problems, current and future, do you want to solve?

It is probably a good idea to consider three wire outlets in the kitchen since 1946 kitchen wire is, by today's standards, undersized. But again, first you must define the problem to be solved.

And for "person safety", as a minimum you should replace the kitchen outlets with GFCI ones asap, labeled as "Unconnected Ground" if as you say you have no grounds available in their boxes. That'll prevent someone from getting electrocuted by an appliance with an insulation fault if they touch it and a water faucet at the same time. (DON'T use a GFCI on the refrigerator outlet.)

You mean you already have *some* 3 prong outlets with no ground connected to them? If you do, you really should label them as "Unconnected Ground". As someone else mentioned, "BX" armored cable was being used in homes back then, and if your home is wired with it, you *may* be able to distribute grounds to all your outlets through the steel armor of that cable, but a check with your local electrical inspector would be in order before doing that.
Jeff

 

[nobertos]

I believe my panel has already been upgraded to 100amps. I was under the impression that i need to 'ground' *every* outlet in my house. Probably by installing a ground rod that attaches to the panel, and then a ground wire from the panel out to an outlet.

Am i high?

 

[Doug Miller]

I believe my panel has already been upgraded to 100amps. I was under the impression that i need to 'ground' *every* outlet in my house.

That is not necessary. Look at the appliances you're plugging into those outlets: the vast majority of them have two-prong plugs and thus do not need a grounded outlet.

Probably by installing a ground rod that attaches to the panel, and then a ground wire from the panel out to an outlet.

Am i high?

For the areas where you need grounded outlets, you can install ground fault circuit interrupters. Google-search this newsgroup; it's been discussed repeatedly here.

 

[w_tom]

As noted previously, earth ground and safety ground are two different grounds required by the National Electrical Code (NEC). A connection to water pipe is no longer sufficient to earth an AC electric system. That connection to water pipe remains to remove elecricity from water pipes. Never make a connection to water pipes to dump electricity into those pipes. This being so important for human safety especially in bath, shower, and sinks.

Current code calls for a dedicated earthing connection. To exceed code requirements, that earthing connection must be as short as possible, no sharp bends, no splices, not bundled with other non-earthing wires, and the ground must be shared by all incoming utilities. That means each the CATV wire must drop down to connect to that single point ground before rising back up to enter the building. This paragraph only discussing earth ground.

Volts500 has provided a good summary of household grounding for human safety, in the newsgroup alt.home.repair entitled "Grounding Rod Info" on 12 July 2003 at http://tinyurl.com/hkjq

A recent discussion in the newsgroup alt.home.repair was "Easiest way to ground a computer" from 5 May thru 10 May
2005.

The only place I would most want three wire outlets is in the kitchen. Especially a dedicated outlet to the refrigerator that cannot be on a GFCI, must be on its own circuit, and that must have a three prong outlet. Kitchen counter tops and things like the garbage disposal, electric stove and oven, etc all do need that third wire safety ground. Elsewhere in kitchens, bathrooms, outside outlets etc can be GFCIed. Also required now is that all bedroom outlets be AFGIed. Same should be installed on any interior receptacle that lights a 'live' Christmas tree. These provide safety not made available with three prong outlets. This paragraph about making power wall receptacles for human safety.

If running interconnected electronic appliances, then either all should run on safety grounded three prong outlets OR all must connect to a power strip so that equipment grounds share a single point connection. For example, computer, its external modem, and its printer should somehow share a common equipment ground. This paragraph more about equipment grounding for transistor safety.

 

[Vic Dura]

As noted previously, earth ground and safety ground are two different grounds required by the National Electrical Code (NEC). A connection to water pipe is no longer sufficient to earth an AC electric system.

Just curious.

It was sufficient for many years. Now it's not sufficient. What changed? Is the electricity we use different?

 

[Charles Spitzer]

Just curious.

It was sufficient for many years. Now it's not sufficient. What changed? Is the electricity we use different?

for one thing, plastic pipes are now used a lot more than in the past.

 

[Mike O'Donnell]

The electricity isn't different, but the water pipe may be..

I did a panel replacment/upgrade in my house a couple of years ago and asked the inspector. He said a lot of water systems aren't using copper pipe as much. The piece of copper coming into your house may be only be a few feet long before it's connected to plastic.

Mike O.

 

[Vic Dura]

for one thing, plastic pipes are now used a lot more than in the past.

Ok, that make good sense to me. Thanks for the explanation.

 

[Jeff Wisnia]

The electricity isn't different, but the water pipe may be..

I did a panel replacment/upgrade in my house a couple of years ago and asked the inspector. He said a lot of water systems aren't using copper pipe as much. The piece of copper coming into your house may be only be a few feet long before it's connected to plastic.

Mike O.

And, if the city pipes are still metal, they may be using an "impressed current" cathodic protection system on them and installed an electrically insulating pipe coupling where their pipe ends and yours begins, to avoid "shorting out" the impressed voltage on their pipes to your electrical system's ground. That was a pretty common technique with gas pipes in some areas too.

Some info on impressed current protection is found in:

http://www.usace.army.mil/inet/usace-docs/armytm/tm5-692-2/chap31VOL-2.pdf

Jeff

 

[w_tom]

First thing that changed is plastic pipe. A plumber need not worry about electricity nor risk electrocution when working on pipes while standing in water. Second, other functions of the earthing system (beyond the NEC's primary purpose) demand an earthing ground connection be short. Connections to water pipes often are well beyond 10 feet. If the code ever fully addresses transistor safety, then earthing requirements would be further enhanced - significantly. Easily accomplished if installed when a house is first constructed. We still don't ground as if the transistor exists.

These solutions (and solutions for the future) can only be accomplished using a dedicated ground. A ground that a plumber will not compromise.

Ground problems created by plastic pipe are not just limited to the earthing ground. Some jurisdictions now require a 6 AWG safety ground wire connected directly from bathtub to breaker box IF the bathtub is metallic. Again, a problem created by plastic pipes and by plumbers who need not know anything about electricity.