Here’s our situation: 90% of the receptacles in our house are the ungrounded two prong type as the house was built in the early 50s. The boxes are metal and appear to be grounded but they are essentially non-grounded so I want to begin replacing the two prong receptacles with GFI receptacles.

Maybe someday when we have the $10-$20,000 to rewire the house, we will get all new wiring and three prong grounded receptacles but that’s not happening right now. The majority of the current 2 prong receptacles are old and worn and sloppy loose and I’m worried mostly about my children’s safety.

What I plan to do is remove each receptacle and pigtail in some hot and neutral wire so I can attach the GFI. I’m not doing the whole upstream/downstream thing just putting a GFI on every receptacle.

My question: do the pigtails need to be the same exact gauge as the wiring in the box? I think it’s all 12 gauge around the house but not sure offhand.

Thanks!

Yes

Yes and 14 gauge is against code I do believe.
I helped my brother do the same thing with an older house he bought.
Make sure and have some type of meter to make sure it's not hot to work on and also to check voltage afterwards.

Something you might consider instead.

Put in a CGFI/arc fault breaker in the panel.

Cost about $60 each and takes 10 minutes to wire in.

I just did 2 circuits with them to replace the GFI outlets that had gone bad.

I think I got hit with a power surged that damaged the outlets.

quote:

Originally posted by sig2392:
Something you might consider instead.

Put in a CGFI/arc fault breaker in the panel.

Cost about $60 each and takes 10 minutes to wire in.

I just did 2 circuits with them to replace the GFI outlets that had gone bad.

I think I got hit with a power surged that damaged the outlets.

But that leaves me with the issue of loosey goosey old 2 prong outlets. Just replacing each with a GFI is more work but solves that.

How long should a pigtail be? 6 inches? 8 inches?

quote:

Originally posted by PASig:
The boxes are metal and appear to be grounded but they are essentially non-grounded

So you have 2-prong outlets, how do you know the boxes are grounded ?

Pretty sure you have bx tied into the box and panel acts as a ground. You can run a screw in the box and tie a ground wire to it and install the newer outlets

^^^Pretty sure that's a Code Violation...

Given his out of date wiring, can he bring the outlets to current code without a full rewire?

quote:

Originally posted by nhracecraft:
^^^Pretty surehat's a Code Violation...

Old existing boxes are probably going to be a tight or worse fit with any new receptacles, particularly gfi.

quote:

Originally posted by motoboy:
So you have 2-prong outlets, how do you know the boxes are grounded ?

Multimeter set to AC voltage. Hot to box would read 120V if the box is grounded.

quote:

Originally posted by motoboy:

So you have 2-prong outlets, how do you know the boxes are grounded ?

When I use my outlet tester like this pic, it lights up when I have one probe in the hot slot and touch the other to the screw:



Some light up more brightly than others. I checked with an electrician at work and he said the boxes must be grounded but it’s not really a good ground and advised against using that as a ground with any upgraded receptacles.

^^^^^^
Ok that is good news.

During this time period they were installing wiring that was either 2-wir hot/neutral or 3-wire hot/neutral with a ground wire that was a bit smaller than the current carrying conductors.

What I will do when called out to your situation is to have my guy pull out a few of the outlets and check how small the boxes are and if the the ground wire is indeed present. A lot of the time the ground wire will be cut short and wrapped around the clamp screw of the box. While he is doing this I go down to the electric panel and pull the cover off. I can then check to see what type of wiring there is and if there are ground wires from the home runs and if they are landed an a grounding bus. I can then give the customer a idea what they are in for.

quote:

Originally posted by Ripley:
Old existing boxes are probably going to be a tight or worse fit with any new receptacles, particularly gfi.

Also this.

They did not seem to have to consider box fill during this time period.

Pretty sure PASig has his answer already but, here's a thread on the identical subject from the end of July:

https://sigforum.com/eve/forum...0601935/m/5680037384

Two posts jumped out as particularly useful...

quote:

Originally posted by ensigmatic:
WARNING: If you are replacing receptacles and the existing wiring has no ground wire, you must not install receptacles with ground connections. Doing so would be both unsafe and a code violation.

quote:

Originally posted by Skins2881:
House built in the 50's will have likely AC cable which the sheathing acts as your ground. If that is the case and you try to replace the box you must use a metal box. Also you must pigtail the outlet to the box or use self grounding outlets. It is also possible you have ragwire ran in your house which 95% of the time does not have a ground. Have you tested the outlet to see if a ground is present?

As someone else mentioned you need to use two prong with no ground or install GFI device/breaker and add the no equipment ground sticker if not grounded.

^^^ That second guy quoted seems pretty smart.

You need to determine what you are dealing with and figure out if the outlets are grounded or not.

Option 1) hire an electrician and have them do it. This is the safest and beats trying to interpret a room full of people on the internet yelling out answers.

Option 2) buy a real tester remove outlets and see if they are actually grounded or not. You will need to check an unfinished area to see if it's AC/BX cable, if connectors were used and if set screws are tight (also tighten all lock rings on each box. Next open your electric panel and confirm proper connectors and tighten lock rings and set screws if accessible (unfinished area).

These options will allow you to replace with standard three prong assuming that the outlets are grounded and save the costs and efforts of shoving GFIs in every outlet box.

Other considerations:

- A GFI may not fit into the existing electrical boxes as they were typically very small. This can be made worse by adding wire nuts into the equation. I wouldn't pigtail if there are only two wires present.

- There is a good chance of damage to the wiring from removing and replacing the outlets. This will be determined by the type and age of the insulation with cloth coated wiring being the most susceptible to damage. If the insulation seems brittle, stop immediately and contact electrician.

- Combining the above two items, the bending radius of the wires will be exceeded in almost all cases by adding GFIs and the box will be crammed full of GFI and wiring and lessen the ability to dissipate heat.

- Possible reasons for inconsistent readings from that testing device are first, it's a crap tester and only function is to test if power is present, in reality you should throw it away and buy a real tester. Second could be poor drywall work or lose screws from yoke to box. If everything is grounded properly and it's just the outlet type/drywall/looseness causing inconsistent readings that's an easily solvable problem. Simply drill and tap a 10-32 hole in the metal box and add a premade grounding pigtail to the box.

I highly suggest investigating further what your existing wiring is and seek professional help at a minimum to recommend what the best course of action is.

Were you able to determine if the outlets are actually grounded?