Confused re wiring
 

A new dishwasher

I removed an old dishwasher that was wired into a box in the wall.
The box and the dishwasher only had a black and a white wire no ground.
I was surprised by the lack of a ground all these years.

Looks like the box was added on when the dishwasher was installed as a bx cable is running up to an outlet that is above the counter. The wall under the counter looks like it was patched when the wires were run.

The new dishwasher had a 3 prong plug. So i wired a GFI outlet to the existing black and white wires and mounted it to a box I nailed to a stud

Seems my dishwasher is not grounded. Will the GFI trip and prevent shock in this case? Or will my circuit breaker trip?

FWIW
My house was built in 1960 and had two prong oulets when we moved in.
We had all the outlets replaced with 3 prong outlets 20 years ago
I'm getting a sinking feeling that all these outlets are not grounded either.

You should really run a new circuit to the DW. By more modern codes it should not be on the counter circuit. This only makes sense, especially in today's world of kitchen appliances.

To answer your question, yes, a GFI will trip without a ground present.

WHO replaced your receptacles 20 years ago?
Is the house wired with AC/BX cable?

Thanks for the answer. Glad to know the dishwasher is safe for now. I will look into getting a dedicated circuit run.


My house is wired with BX cable. When we moved in my in laws had a friend of theirs son change the plugs. He was supposed to be someone who worked with an electrician. I owned 1/2 the house back then with my in laws who have since passed and now my wife and I own the whole shebang. I've just started doing work on the house besides maintenance.

I'm going to take some outlets out this weekend to see if they are grounded.

If this old BX is actually AC cable with the thin bond strip inside that is your ground as long as all the connections are made up tight and sound.

Interesting. There was a very thin piece of wire in the cable.

I inserted the black and white wires into the small holes in the back of the plug tightened the screws. Wrapped it up with electrical tape

The BX/AC cable went into the top of the box and is held in by a connector for armored cable.

Speedy Petey - I do not believe this is correct. A lack of a ground will NOT cause a GFCI to trip. In fact - Adding a GFCI to an ungrounded circuit will add protection. Adding a GFCI to an ungrounded circuit is allowable by code as long as the outlet and downstream ones are labeled as having no ground. A GFCI in this scenario does not provide an equipment ground but will prevent electrocution. The GFCI package should come with stickers to label an outlet as ungrounded.

That's not what I said. At least it's not what I meant.

I didn't say it would cause it to trip. I meant it will operate properly without a ground present.
I see how I wrote it it could be misunderstood.
Sorry 'bout that.

speedy check for proper wireing...
 

I have been through the same thing. Most home improvement stores sell a nifty little tester for checking 3 prong outlets. it can indicate no ground, open ground, hot/common reversal and other things. If it shows a problem, then you can investigate, if not move on to the next....

Mike

Speedy - I re-read what you wrote. Yes, I agree "a GFI will trip without a ground present" and you agree with me that "A lack of a ground will NOT cause a GFCI to trip" We also agree that "a GFI will not trip without a ground present" English is a funny language.

No, I certainly do not agree with this statement.

To quote post #7: "I meant it <a GFI> will operate properly without a ground present."