ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat
Recent Posts
Increasing demand factors in residential
by gfretwell - 03/28/24 12:43 AM
Portable generator question
by Steve Miller - 03/19/24 08:50 PM
Do we need grounding?
by NORCAL - 03/19/24 05:11 PM
240V only in a home and NEC?
by dsk - 03/19/24 06:33 AM
Cordless Tools: The Obvious Question
by renosteinke - 03/14/24 08:05 PM
New in the Gallery:
This is a new one
This is a new one
by timmp, September 24
Few pics I found
Few pics I found
by timmp, August 15
Who's Online Now
1 members (Scott35), 269 guests, and 13 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
Page 1 of 2 1 2
#219427 07/06/18 06:44 AM
Joined: Apr 2008
Posts: 25
N
Member
I got called to a customers island house on the 4th because they were getting shocked off the outside water spigots.
Customer was barefoot, standing in a puddle, showing me where he feels a shock. I used a meter instead.
Two outside water spigots, both had voltage to ground, 7 volts on one, 14 on the other. The spigot with 7 volts was 5 feet from the 2 ground rods at the service entrance. I shut off power to the house(meter/disconnect) and nothing changed.
I told customer I would contact utility about a possible neutral issue and suggested he stay away from tie spigots until the power company checked it out.

I called the power company the next day and spoke with the head lineman. After explaining the situation he started giving me grief for grounding the water pipes and if I hadn't this problem wouldn't happen!
So, I had to explain to the head lineman why we bond water lines along with other things, then explain why this voltage is happening, why I felt it was a power company issue and he needed to go and check things out.
He finally agreed to go look, but I don't have high hopes for a solution from them.

While in the shower last night and thinking about this an idea came to me. If I were to purchase a couple of 4x8 sheets of stainless steel expanded metal grill and bury one under each spigot, attach a #6 solid bond wire from the metal grill to the water spigot above, I think my shock potential would go away. There would be no way to contact the water spigot with out standing on the metal grid ( which would only be a couple of inches below grade).

Just throwing this problem/solution out there for feed back before I pitch it to the home owner. Has anybody had a similar problem and what did you do? I don't have high hopes for a power company solution and want to be sure my customer and the army of kids around stay safe. While the 7 to 14 volts may not be lethal, my opinion is it shouldn't be there at all and could it all of a sudden get worse.

Thanks for any input
Dave

Joined: Mar 2004
Posts: 947
T
twh Offline
Member
It's a good idea. Google ground mesh.

Joined: Jul 2004
Posts: 9,923
Likes: 32
G
Member
I would beef up the ground electrode system and be sure all of the connections are tight.
It is not unusual that the "neutral" from the utility is not really "ground".
The only fix is to try to be sure "ground" is as close to earth potential as you can at the home.
I would certainly start by checking the ground clamps on the rods. I was getting bit when I first moved in here and I made it a whole lot better, just by replacing the clamps.


Greg Fretwell
Joined: May 2005
Posts: 984
Likes: 1
G
Member
If the water pipe is bonded to the main Service ground and then connected to a ground mesh at the faucet; won't that mean that the electrical service is grounded at more than 1 point?


Ghost307
Joined: Apr 2002
Posts: 7,381
Likes: 7
Member
Ghost
Think of a ufer terminated on the neutral conductor at the first OCP, and then 2 rods, and metalic water main (IF avail). Grounding/bonding.


John
Joined: Apr 2002
Posts: 7,381
Likes: 7
Member
NH Sparky:

I agree with Greg. Check all the terminations. Pipe clamps and clean pipe.

Now, could this be one of those 'stray voltage' conditions? Or a neutral issue at an adjacent service?


John
Joined: Jul 2004
Posts: 9,923
Likes: 32
G
Member
If you have wye distribution you will always have stray voltage. It just can't be avoided. The voltage drop in the PoCo neutral is going to show up on the grounding conductors, throughout the system. I have about 3a on my neutral to the PoCo through my GES with the power off. My GES may be the best ground electrode on my street tho. I just try to be sure everything around the house is bonded to my "ground" so I don't have gradients.
You can have all the electrodes you want, as long as they are bonded together with the appropriate conductors. I am a fan of "the more the better". I have 6 rods around the house, 2 "building" Ufers and the King Kong of all Ufers, an in ground concrete pool.


Greg Fretwell
Joined: Jul 2002
Posts: 8,443
Likes: 3
Member
NHSparky,
Don't use Stainless Steel, it has elements that cause electrical resistance and unless you have a TIG welder, joining anything to it (you need a welded joint) can be problematic.
The question I ask, does the PoCo have a guy that isn't the Head Lineman, like a Senior Technician, that investigates things like this?
A response like you were given, is not good enough, because this is a Line-side fault, either with the Neutral or poor Grounding at the transformer.
It is up to the PoCo to get this sorted.
Let us know how you get on with this, because I used to do this sort of thing all the time.

Joined: Oct 2000
Posts: 5,392
S
Member
The problem is we exist (USA & many countries) in a TN−C−S earthing system.

If it's wye (poco) wye (consumer) , any M.E.N. is transmitting the unbalanced.

Fact is, the closer you get to a substation, the more your GEC's are simple a noodle


The normal mindset being 'if it doesn't move ground it' can work, as long as it's all 'bird on a wire' equopotential (sp?, you know what I mean...)


So go ahead, bond the living daylights out of it all, I have in similar past circumstances & walked away the hero w/$$$ in hand



The truth is, I've simply aided and abetted the perp

~S~

Joined: Jun 2014
Posts: 146
Likes: 3
D
dsk Offline
Member
We have IT system where I live, it is pretty common in older buildings here in Norway
The local grounding and bonding is not connected to any live wires, and all power carrying wires are deemed to be live.
127 V live to ground until first failure in the system. This is usually kept there by capacity between wires and ground.
The transformers are usually Y but the center is not connected to ground. (an overvoltage "fuse" are common, grounding on error) The voltage between the legs are usually 230V (50Hz).

Page 1 of 2 1 2

Link Copied to Clipboard
Powered by UBB.threads™ PHP Forum Software 7.7.5