Adding ground to 1959 2-prong outlets...Stumped

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Old 01-26-20, 05:36 PM
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Adding ground to 1959 2-prong outlets...Stumped

Hi all. This is my first post.

I just moved into a modest house built in 1959. All the outlets are 2-prong, but I got lucky. The metal outlet boxes all appear to be wired together and grounded to the service entrance.

I've been going from outlet to outlet, exchanging the old 2-wire 3-plug outlets for modern grounded outlets. So far all I've had to do is swap in the new outlet, add a 10-inch length of 12ga solid copper ground wire, screw it into the back of the metal box and connect it to the new outlet's green ground screw.

Today I hit a snag. I performed the usual operation on a bedroom outlet that was working, but now is not working. (I could be wrong, but) the original wiring was:
- Two (2) white wires attached to the left terminals of the original outlet
- One (1) black wire attached to the bottom right terminal of the original outlet

I have one of those yellow 3-prong grounded outlet checkers. It was indicating HOT / GRD REVERSE (aka OPEN NEUTRAL?) I've tried every wiring configuration and now the outlet is just plain dead. Tried exchanging a fresh outlet, but no dice.

With the new outlet wired as the original was (as best I can recall...duh) I put a voltmeter across the terminals and get "4." If I remove the outlet and put voltmeter leads on black and either white ground I get "4." I put voltmeter leads on black wire and metal outlet box, I get "4."

BUT...if I put leads on either white wire and the metal box I get 118 volts. =O Is something shorting out on the metal box? That box is hot. I found out when I got "the jolt" from touching a white wire and the box.

FWIW, when I connect the new outlet as (I think) it should be, the other outlets on the circuit register CORRECT GRND per the yellow outlet checker. I've blown many hours on this today. I'm a "DIY Generalist" and not an electrician, so any help is much appreciated.

Thanks,
Tom
The attached image might be of no help. I'll do my best to clarify / answer questions. As best I can tell, the WHITE wire on the right comes in from the bottom right. The WHITE wire on the left comes in from top left. BLACK wire comes in from bottom right. Wires continuing through the circuit were wrapped in black tape (c.1959). My new GROUND is a piece of solid 12ga sheathed in BLUE because that's all HomeDepot had on hand.
 
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Old 01-26-20, 05:59 PM
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Did you try turning on the wall switch?
 
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Old 01-26-20, 06:22 PM
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I can't believe I did that. You're absolutely right, Joe. I forgot this is a switched outlet.
Reinstalled the new outlet, turned on the circuit, then turned on the wall switch.
It works.

Duh

 

Last edited by TomOverthere; 01-26-20 at 07:32 PM.
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Old 01-26-20, 07:51 PM
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The ground should be bare or green. It should not be under the clamp screw. The ground should be under a screw used for no other purpose. It should also be spliced to any ground in the box.
 
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Old 01-27-20, 05:26 AM
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Hi, you should have 2 blacks in that box, itís a bit hard to see in the pic but it looks like one of them is going back up through the clamp, is it?
Geo
 
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Old 01-27-20, 07:14 AM
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There are other errors that you can probably take a breath and then fix (or fix at your leisure).

Two whites and only one black coming into the box and wired up to the receptacle is not right. A secod black had to accompany the second white.n

Measuring line voltage between white and the box (not to mention getting shocked touching those two items respectively) is definitely wrong.

There are some bare wires, probably ground wires, entering the box and squashed between the clamp and the box or something like that. So you do have grounding altough the work looks sloppy enough to me that I am not convinced that the grounding connections are tight enough daisy chaining all the way back to the panel. h

Other errors that could exist in 1959 wiring are switching the neutral instead of the hot. In whch case flipping the switch will leave energized wires and terminals and appliance/light interiors in unexpected places.i

 
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Old 01-28-20, 05:12 PM
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Guys, I appreciate all suggestions and concerns but I'm not able to rewire the entire house. The existing system is wired as you see it, and has been in use for sixty years. I'm just trying to provide grounded outlets throughout. As a layman, I'd say the metal boxes ARE all grounded to the service entrance - each time I add a ground to the box the outlet tests as CORRECT GROUND (2 yellow lights).
 
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Old 01-28-20, 06:55 PM
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The question remains is the grounding an effective ground fault path to allow the breakers to trip. Simple contact may show grounded but not allow the breakers to trip.
 
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Old 01-28-20, 08:54 PM
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I see what appears to be a ground wire from a cable in the bottom of that box. I would be fishing that out so it can be used to properly connect the grounds.
 
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