2-Wire Non-grounded Electrical System - Questions

1,452 Views | 10 Replies | Last: 7 yr ago by dubi
Cru
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S
We are in the process of purchasing a home. It is an older home (built ~1955), and has a 2-wire non-grounded electrical system.

I know nothing about electricity.

  • Is this a human safety hazard?
  • Is this an appliance hazard?
  • Aside from re-wiring the entire home, do I have any options to ground the outlets?
  • Is it common to just ground those outlets that need to be grounded (ie kitchen, office, bath, garage, entertainment areas)?

We do plan to replace the electrical panel.
The Fife
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Cru said:

We are in the process of purchasing a home. It is an older home (built ~1955), and has a 2-wire non-grounded electrical system.

I know nothing about electricity.

  • Is this a human safety hazard? Nope
  • Is this an appliance hazard? Not really
  • Aside from re-wiring the entire home, do I have any options to ground the outlets? Replace with GFCI outlets, put a sticker that comes with on the faceplate that says 'No Equipment Ground
  • Is it common to just ground those outlets that need to be grounded (ie kitchen, office, bath, garage, entertainment areas)? I wouldn't worry about it so long as breakers are the right size for the wire and the wire itself is in good condition.

We do plan to replace the electrical panel.
akaggie05
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AG
Assuming the house is on a pier and beam foundation, one way you can add a ground to individual outlets fairly easily is by running a ground wire down to the crawlspace and clamping to a cold water pipe. I did that at my parent's 1955 house a few years ago for a couple of outlets that ran computers, AV equipment, etc.
The Fife
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I wouldn't use a pipe, it sounds like a good way to end up with a floating neutral, or no ground at all if a section was replaced with something non conductive.
Cru
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S
Thanks, The Fife!

  • Would each outlet I want covered need a GFCI outlet, or just the first in a branch?
  • I assume it would be best to have new wiring run to the appliances, yes?
  • If no hazards exist due to this, what is the point in any of this?
  • What should I really be looking for, and testing against when speaking to electricians to know that I do need this, and they aren't full of a fear mongering sales pitch?
akaggie05
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AG
Well, part 2 of my recommendation should have been to make sure that whatever you bond to has a good earth ground. Not sure how you'd get a floating neutral, as neutral remains wired back to the panel, through.
The Fife
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You're right, typing while "watching" our baby. But yeah, one of those things that would work in theory but in practice there can be unintended consequences.
The Fife
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Cru said:

Thanks, The Fife!

  • Would each outlet I want covered need a GFCI outlet, or just the first in a branch?
  • I assume it would be best to have new wiring run to the appliances, yes?
  • If no hazards exist due to this, what is the point in any of this?
  • What should I really be looking for, and testing against when speaking to electricians to know that I do need this, and they aren't full of a fear mongering sales pitch?


-All of em, at least any you plan on putting anything with 3 prongs in
-New wiring doesn't hurt, assuming it's in good shape and correctly sized you don't have to though. We replaced all of our wiring for appliances because they were moving to new locations and there was no point to re-running the old stuff.
-assuming no defects, peace of mind or a selling point later if you're not planning on staying long
-is it correctly sized, and is it in good condition. That's really what it comes down to. Just because it's old doesn't mean it's bad, condition is what's important. You probably have copper with insulation similar to what's used now and a woven, coated jacket. It's not old style knob and tube.
pasquale
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AG
Give Mark with Luchak Electric a call. He can give you some advice and even take a look if need be.
281-450-2673
Lone Stranger
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I'll give you a little different perspective. An old 2 wire system is fine if all your electrical equipment is "double insulated" and has 2 prong plugs. That way if it shorts, it won't energize anything the user can touch on the metal case of the equipment. Think about drills, etc that have 2 prong cords vs equipment with 3 prong cords. The 3 prong stuff isn't double insulated so it has the equipment grounding conductor (3rd wire) connected to the metal case of the equipment so that when it shorts it can trip the breaker and not hurt someone.

GFCI's can be added to 2 wire systems (as mentioned) where you need to use your 3 prong equipment and you are actually safer than simply being grounded with the 3rd prong. Yes....you can put the GFCI as the 1st plug in the run and it will protect the regular downstream outlets. GFCI's don't need the 3rd grounding wire to function. Advantage: saves money on installation cost. Downside: When something trips the GFCI upstream, which outlet/device downstream caused it to happen....takes longer to troubleshoot where the problem is.

The modern 3 wire system is made to accomodate both the 2 wire double insulated appliances and 3 wire metal cased commercial equipment without any loss of grounding issues for the 3 wire equipment. The 2 wire system isn't as accomodating/safe for 3 wire equipment without putting in some additional effort, work and/or expense.
Copp
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Reasonable electrician can ground your outlets fairly easily. Some may require you cut a small line in Sheetrock if it is a slab but pier and beam are really easy and very minimal as far as damage.
dubi
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AG
Older homes didn't have a separate circuit for each appliance so that is what we did in our 1960's house.

So basically the kitchen added new circuits in our electrical box.

We added GFCI circuit breakers for the bathrooms.

We use power strips for anything of value.

Everything else is the same. FYI, our house is 3 wired.
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