Residential two wire electrical wiring

[chicopee]

I do not know if this is the right forum but here we go. A house in Dayton,Ohio built about 50 years ago and with four previous owners had some of its electrical wiring at some point in time upgraded to include a C.B. feed box.. I noticed throughout the house that some electrical boxes fitted with three prong outlets were fed with the original two wire electrical conductors and that the ground connection was thru solid bare Cu. wiring terminating at the closest water lines.
Is this practice safe, legal and in compliance with the residential electrical code?

 

[waross]

It's a lot better than nothing and was code compliant at one time. You may want to run the wires to the ground bus in the panel. Note, many small panels use the panel itself for the ground bus.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[PHovnanian]

What Bill said. At least, make sure that there is some bonding between your grounded conductor (neutral, at the service entrance), this water pipe ground connection and a good ground rod. Otherwise a ground fault will just pull the water pipes up to the system voltage.

But keep in mind that doing this work legally (with permits and all) might resulting your local inspector insisting that your grounding system be brought up to code with a ground bus in the panel and ground conductors extended to this point.

 

[chicopee]

OK!! thanks a lot to both of you. I'll follow the suggestions.
Waross, when you said to run the wires to the ground bus in the panel, are you refering to the ground wires? I think that you are but I just want to be certain.

 

[DaveMeharg]

The current electrical code does not allow the equipment ground wire on a recepticle to be connected to the nearest water pipe (unless the connection is made within 5 feet of where the water pipe enters the building - see NEC code section 250.68C1). This could be a real hazard if the water pipe is not properly bonded to electrical system or there are fittings in the pipping system that make it not an effective path back to the electrical panel where the water pipe should be bonded to the electrical system on both sides of the water meter. I would expect an inspector would fail this installation.

 

[waross]

Yes. Extend the ground wires back to the panel.
At one time the code allowed updating ungrounded branch circuits by connecting a wire to a metallic piping system. This was long before the emergence of insulating couplings. The installation may have been a code compliant installation at the time that the ground wires were installed.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[stevenal]

I believe NEC allows the use of GFCI three prong receptacles as a retrofit for ungrounded two wire installations. Much easier than pulling wire.

 

[chicopee]

Instead of ground fault receptacles, about replacing CB's with GFCI integrated into CB's?

 

[stevenal]

"A non–grounding-type receptacle(s) shall be permitted
to be replaced with a grounding-type receptacle(s)
where supplied through a ground-fault circuit interrupter.
Grounding-type receptacles supplied through the groundfault
circuit interrupter shall be marked “GFCI Protected”
and “No Equipment Ground.” An equipment grounding conductor
shall not be connected between the grounding-type
receptacles."

A GFCI breaker fits the bill, but technically you are not replacing a non-grounding receptacle. Spirit but not quite the letter of the code. Might want to run it by the inspecteo