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Recently bought a flip house. The flippers replaced every two prong receptacle with a three prong and a bootleg ground. In the process of undoing that unsafe practice, I've discovered that almost all the boxes in my house have "Boston back wraps". The NM cable ground is wrapped around the sheathing of the cable and clamped under the box's cable clamps.

Similar to the connection on the right in this picture.

enter image description here

I have a sneaking suspicion that grounding the receptacles to the box (like you would with old BX cable installs) is insufficient in this case. It just doesn't seem like these back wraps can offer a good ground all the way back to the panel.

So what would be your preferred way to address this?

I see two options:

  1. Treat it like a two-wire circuit and GFCI protect everything (potentially with gfci/afci breakers). Potentially a whole home surge protector as well.
  2. Carefully unwrap the Boston back wraps connect the grounds like a modern install, bonding the boxes with a pigtail or self bonding receptacle.

I'm tempted to go with route 1, as it seems to offer a high degree of safety with minimal work. Route 2 seems like a lot a additional trouble for arguably no additional or even less safety benefit. The only part that doesn't thrill me about route 1 is the receptacle labels (no equipment ground) might not look great to home buyers in the future.

Thoughts?

  • Can you measure the gauge of the ground wires? Also, how open are you to retrofitting ground wires, or is there a reason that'd be impractical? – ThreePhaseEel Oct 30 '18 at 23:13
  • How old is the house? Is it of an age that it should have been built grounded? – Harper Oct 31 '18 at 1:50
  • Looks to be 14 ga, but might be 16 ga- good point, if it is 16 it can't be used as an ECG at all. Not particularly open to retrofitting if it can be made safe and compliant without opening walls. – Brandon Steeves Oct 31 '18 at 2:03
  • It's a mid 50s house. Code for the time (or at least code didn't exist yet), but never intended to be used with three prong receptacles. – Brandon Steeves Oct 31 '18 at 2:04
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Just fix them right, do a room a day and it will be done before you know it.

You could swap in GFCI breakers temporarily if you can't get to it for a bit.

Be prepared to discover other deficiencies.

  • "Do it right" as in route 2? Both of the options I listed should be fully code compliant but I admit that grounding the receptacles feels more correct, even if they are both safe and correct. – Brandon Steeves Oct 31 '18 at 2:09
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    @BrandonSteeves - I am afraid the code provisions that allow you to use three-wire receptacles without a ground wire are just for repaclements when there's no ground wire or other means of grounding present in the box so simply grounding the receptacles is your only code compliant option. – batsplatsterson Oct 31 '18 at 7:51
  • @BrandonSteeves - the GFCI will provide protection from in the event that there's a ground fault, but the grounding system does serve other functions. For example, most surge protectors won't provide full protection with a floating ground. – batsplatsterson Oct 31 '18 at 7:56

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