open ground system


Old 09-18-00, 08:08 PM
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I recently bought a home which was built in 1959, one year before most homes were built with grounded electrical systems. I was not present at the inspection and the inspector listed our home as having mostly "open ground system". What does that mean? open ground? mostly?

It also says we have copper conducting and two wire romex wiring. There is a GFCI outlet in the bathroom.

I am under the impression that the wiring does not contain the third ground wire. Okay, the next question is how to change that? Can I simply replace the recepticles?
How do I protect my home electronics? I would also like to plug things in without an adaptor.

I have looked at some books, but I am still unclear with what I am working with. I am willing to do as much research as possible to avoid paying a professional...however, I would rather pay a professional if my and my families safety is at risk.

Any ideas or suggestions?

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Old 09-18-00, 08:35 PM
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Okay... after reading a bit more I understand this may be a common dilemma.

So to paraphrase the above...

What is the definition of a "open ground system"?
And what is ment by "mostly"?

Is my only option in changing to 3-prong outlets to use a GFI outlets?

So I will never be able to ground the outlets to protect electrical equipment?

What about those self-grounding outlets?

What do people normally do in this situation?

Old 09-18-00, 08:49 PM
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An open ground system is a two wire system that has no equipment grounding conductor {bare wire}

Many old homes have this type of wiring. It still works but is not real compatible with the electronic world of today.

A self grounding receptacle is a device that has a spring loaded clip that rests against the steel box that has been grounded with the third wire that you don't have or with a conduit that you don't have. All it does is complete the path from the yoke of the device to the steel box. It does not create a ground source for you.

Yes if you change your receptacles that are fed with a two wire system and install a three prong receptacle then the GFI must be installed. It is designed to act as the third wire. It is not perfect but it is better than nothing. The NEC says that you can replace this old two prong receptacle with either another two prong receptacle if you can find them or with a gfi protected three prong receptacle.

A lot of the time people will take the option of a complete rewire replacing all the old wire with the new romex made today with a grounding conductor in the cable.

A lot of the time people will take the option to do what they call a partial rewire. This means installing new romex to all heavy loads such as kitchens, laundry, etc. Where the heavy loads of the house is located. This is on the principle that an old horse can still pull the wagon of straw but not the wagon of coal as he did when he was young. The horse does not really have to be put to pasture and useless. Just lighten the load on the old wiring. If you take this option then I would pay special attention to computers etc. that are electronic based. These should be fed with new wiring also for the protection of the electronics. Electronics are fragil and don't take charges such as surges from lightening etc. well. It is ok to replace the old receptacles in the bedrooms, living rooms, and other living areas where the load is light and protect these circuits with GFI controls at the panel or start of those circuits. Then you can replace the receptacles in those rooms with normal three prong receptacles and have the Gfi act as the third conductor.

Good Luck

Hope this helped

Old 09-19-00, 02:56 PM
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Keep in mind the case of electronic gear,
they might require a true ground, to drain
EMI/RFI, surges, and ground loops, which
an ungrounded GFCI will provide only safety,
should the chassis of equipment get connected
to the hot somehow.

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