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Discussion Starter · #1 ·
Doing a remodel and found a bare 16 ga CU wire soldered to the metal box @ the lights and to the copper plumbing in the bath rooms and kitchen ..
I suppose this was the method of grounding . the house had 12-2 nonmetallic (clothe wrapped),. I was curious how this type worked in case there was a short in the light. The light also had the only plug in the room ,so any appliances would also use this for the ground.
 

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Assuming the copper pipe was a continuous run of unbroken cold water pipe it would have carried any load to ground and blown the fuse or tripped the breaker. It would also throw the current to plumbing fixtures until it blew or tripped. It is not a legal procedure now and may or may not have been in 1962.


To the best of my unlicensed knowledge a continuous ground wire may be run separately provided it returns to the panel box and that panel box is properly grounded.


The gottcha with that is that in the early 60's the house water main was often used as the only ground and that is why someone chose this shortcut method to ground the bath and kitchen.


I would encourage you get the proper grounding installed if that condition stills exists.
 
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That way to ground boxes in kitchen and bath, possibly other rooms, was common until they started including a ground within the Romex. Unless you plan to rewire, it is better than nothing. I really think that cloth wire is older than the 60's, but perhaps the electrician was using wire he had left over.
 

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Discussion Starter · #4 ·
That way to ground boxes in kitchen and bath, possibly other rooms, was common until they started including a ground within the Romex. Unless you plan to rewire, it is better than nothing. I really think that cloth wire is older than the 60's, but perhaps the electrician was using wire he had left over.
I was guessing @ the age ,just from it being on a slab instead of pier and beam

The panel box must be grounded to the copper pipe @ another point in the house, completing the circuit?
I never understood how a ground wire tripped the breaker when using a grounded tool .anyway.
Long ago I saw Bob Villa throw a drill into a bucket of water and the drill kept on running
time for some study online !!
 

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It would be important in this case that the breaker panel be bonded tot he water system to complete the ground path through the pipes.
FYI in Canada it is legal to ground to the bonded metal water lines.
 

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Water pipes, ground rods and ufers are mostly for lightning protection since they aren't reliable low resistance paths for branch circuit faults.

The bonding jumper that connects the equipment grounding conductors to the neutral conductor provides the best low resistance path for the branch circuit fault current to flow back to the source transformer.

In the OP's case, that ground connection may or may not be capable of tripping the breaker. If that water pipe is bonded to the main panel and there is a bonding jumper connecting it to the neutral, it will do until times get better.
 

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The "retrofit ground" part was illegal until NEC 2014 was adopted. Now it's legal.

The idea of grounding *to a water pipe* has never been legal. The retrofit ground needs to run back to any of

- the service panel the hot+neutral come out of
- A junction box which has sufficiently large ground wire back to panel (e.g. same size or larger, or -2 numerical sizes or larger if aluminum).
- A junction box connected by metal conduit back to that panel.
- The Grounding Electrode System, which is the wiring between the panel and the ultimate "ground rod" (or Ufer or water pipe). Not the water pipe itself.
 
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