1950's Electrical Ground


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Old 03-12-06, 07:28 AM
H
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1950's Electrical Ground

My house was built in the 1950's Electrical outlets in the bedrooms are 2-prong outlets without electrical ground. Yet, outlets in the kitchen and garage are 3-prong outlets with ground (according to my circuit tester).

I guess I have two questions:
1.) What was the rationale in the 50's for grounding some outlets but not others?
2.) How can a do-it-yourself homeowner "properly" ground the bedroom outlets to accept a modern 3-prong device like a computer?

I've read conflicting advice on using a home's cold water pipes as a ground path. My home is built over a crawl space so I should be able to run wires without too much difficulty.

Thanks in advance.
 
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Old 03-12-06, 08:22 AM
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1. I'm just guessing, but i assume that because of the numerous small appliances on the kitchen counter, it needs grounding more than most rooms. And of course PCs didn't exist in the 50s.

2. The advice we commonly give here is to install a new circuit with new outlets for your computer equipment. This is no more difficult than trying to provide grounding, and it offers the advantage of giving you modern wiring, additional power, and additional outlets (all of which you probably need in a 50s house) in addition to the grounding.

The cheaper and quicker alternative is to install a GFCI receptacle where you want to plug in your computer. This puts your computer at a variety of risks, including static shock and surges (since surge protection won't do much on an ungrounded circuit). The comupter might also have occasional unusual problems (what else is new) without grounding. So this is definitely a less-desirable solution, but it's easy and cheap.

Using nearby cold water pipes for grounding is illegal in the U.S., but legal in Canada if your cold water pipes are connected to the panel ground.
 
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Old 03-12-06, 03:58 PM
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Just because your tester says they are grounded does not mean they are grounded. There are easy ways to fool those testers. Check at the panel and see if you have ground wires on the cables for those circuits. If you do then you might have grounds in the boxes for the other circuits. I can't see someone using two different types of cable to wire one house.
 
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Old 03-12-06, 07:12 PM
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My guess is that there was a kitchen renovation done some time since the house was constructed.
 
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Old 03-13-06, 04:39 AM
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My house was built in the 1950s. 1958 to be exact. With the exception of the kitchen and dining room, all original 120 volt circuits were 15 amp, 14-2 without ground. The kitchen was wired with a single 20 amp circuit 12-2 with ground, but a smaller gage ground wire. One dining room receptacle (common wall with kitchen) has this same 12-2 with smaller ground wire, and the other dining room receptacle was run from one of the kitchen receptacles with 12-2 without ground.

My house is part of a development. The houses were all built extremely well and all up to code at the time. I don't think they exceeded code, so I can only speculate that a ground was required for kitchens at the time.
 
 

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