grounding plumbing?

Archive Public Archive
#1

Originally Posted By: srowe
This post was automatically imported from our archived forum.


This is probably an “electric 101” question.


Inspected a house from the 50's, most of the house has been replumbed with cpvc, water heater is not grounded, supply lines are obviously not grounded,

What would the deal be on the cast iron waste lines? I need some good grounding answers. Thanks!

#2

Originally Posted By: phinsperger
This post was automatically imported from our archived forum.


Shawn,


Are you asking about the service panel grounding to the the plumbing? This is one way the system may be grounded. Another (esp if you have plastic pipes) is to have the electrical system with its own grounding rod and a wire attaching it to the service panel. If the cast iron waste pipes are continous (no rubber or plastic connectors) they may also provide a grounding source but this is less common as the pipes rust more. The electricial who installs a gound to the cast iron pipes should check for good ground and use lots of paste.

--
.


Paul Hinsperger
Hinsperger Inspection Services
Chairman - NACHI Awards Committee
Place your Award Nominations
here !

#3

Originally Posted By: anatol polillo
This post was automatically imported from our archived forum.


Shawn,


If you found no ground at the meter or the panel, I would recommend sparky to the rescue. If the main water line from the street is copper, there may be a ground tied to it. I don’t think cast iron is a good choice for a path to ground.


Anatol

#4

Originally Posted By: srowe
This post was automatically imported from our archived forum.


There is grounding rod and ground at panel. Electrical was updated with 200A service, I don’t know when if it was before or after the plumbing upgrade. Just about all of the abandoned galv. is still in place, just not operable.


So, new cpvc with cast iron and plastic waste does NOT need ground? right?

#5

Originally Posted By: phinsperger
This post was automatically imported from our archived forum.


srowe wrote:
There is grounding rod and ground at panel.


Assumming the rod is propperly bonded to the panel then yes, the pipes do not generally need gounding.

I say generally because in some older homes that were originally wired with 2 conductor ungrounded wire and were three prong outlets were later added, a separate grounding wire may have been bonded to the neares water pipe.

--
.


Paul Hinsperger
Hinsperger Inspection Services
Chairman - NACHI Awards Committee
Place your Award Nominations
here !
#6

Originally Posted By: Mike Parks
This post was automatically imported from our archived forum.


Shawn


Good point.

I never thought of cast iron as other metal pipe. 250.80 in my 1993 NEC, the first one that I grabbed.

This would take a big bonding strap!

Mike P.

#7

Originally Posted By: roconnor
This post was automatically imported from our archived forum.


Quote:
Other Metal Piping
... metal piping systems, including gas piping, that may become engerized shall be bonded to the service equipment ...

Same thing in IRC E3509.8

--
Robert O'Connor, PE
Eagle Engineering ?
Eagle Eye Inspections ?
NACHI Education Committee

I am absolutely amazed sometimes by how much thought goes into doing things wrong
#8

Originally Posted By: Mike Parks
This post was automatically imported from our archived forum.


If the cast is in contact with the earth (underground section) for more than 10’ would it be an electrode?


Mike P.

#9

Originally Posted By: roconnor
This post was automatically imported from our archived forum.


Mike Parks wrote:
If the cast is in contact with the earth (underground section) for more than 10' would it be an electrode?

It's not metal water pipe so I don't think it qualifies there. But it could be a "pipe electrode" if listed for that ... not likely though.

It looks like the out for not bonding CI waste piping might be the fine print note (FPN) after NEC 250.104.B ... implies that not all metal piping and ducts must be bonded.

Just my 2-nickles

--
Robert O'Connor, PE
Eagle Engineering ?
Eagle Eye Inspections ?
NACHI Education Committee

I am absolutely amazed sometimes by how much thought goes into doing things wrong
#10

Originally Posted By: jmyers
This post was automatically imported from our archived forum.


All this talk about the water pipes, metal that is, has gotten me to thinking about a situation that I recently came across. Service cable (4/0 aluminum for a 200 amp panel), running across the metal (copper) water line in a house. Of course everyone knows there is not way to disconnect the power, since it is after the meter but before the panel.


How would you write this up? Would you write this up?

Joe Myers

#11

Originally Posted By: jpeck
This post was automatically imported from our archived forum.


That abandoned galvanized water supply pipe would not qualify as a rod or pipe electrode because: It is not driven in 8 ft below grade or at an angle not to exceed 45 degrees, or unless it is buried in a trench 30" deep. I doubt the water line is is at least 30" deep (unless you were in a frost area of 30" depth or more, then it might. It also will likely not meet the requirements of rod or ground electrodes because it is probably black iron pipe (see second code reference).


G) Rod and Pipe Electrodes. The electrode shall be installed such that at least 2.44 m (8 ft) of length is in contact with the soil. It shall be driven to a depth of not less than 2.44 m (8 ft) except that, where rock bottom is encountered, the electrode shall be driven at an oblique angle not to exceed 45 degrees from the vertical or, where rock bottom is encountered at an angle up to 45 degrees, the electrode shall be permitted to be buried in a trench that is at least 750 mm (30 in.) deep. The upper end of the electrode shall be flush with or below ground level unless the aboveground end and the grounding electrode conductor attachment are protected against physical damage as specified in 250.10.

Cast iron sewer pipe does not meet the requirements for pipe electrodes.

(5) Rod and Pipe Electrodes. Rod and pipe electrodes shall not be less than 2.5 m (8 ft) in length and shall consist of the following materials.
(a) Electrodes of pipe or conduit shall not be smaller than metric designator 21 (trade size ?) and, where of iron or steel, shall have the outer surface galvanized or otherwise metal-coated for corrosion protection.
(b) Electrodes of rods of iron or steel shall be at least 15.87 mm ( in.) in diameter. Stainless steel rods less than 16 mm ( in.) in diameter, nonferrous rods, or their equivalent shall be listed and shall not be less than 13 mm (? in.) in diameter.

--
Jerry Peck
South Florida