I was called out to a new house (3 yrs old) to check out some problems the owner was having with his electronic equipment for the Home Theater. I didn't find anything wrong with the circuit (polarity, loose neutral, etc.). However, when I went under the house I found a #4 stranded ground wire with a pipe clamp just lying there on the ground. I wasn't sure if this was for the water bond or ufer. I checked the panel (200 Amp) and there was no other grounding/bonding wires on the neutral bar besides the #4 that went under the house. I checked the line side of the panel to see if they landed in that space but there was nothing.
I crawled around the house checking on top of the stem wall for a ufer but found none. I figured the electrician/concrete guy forgot to put one in and the electrician just threw the wire under the house and hooked it to the panel to fool the inspector. So, I'm guessing this may have something to do with the electronics issue. Yes? Is there a possibility of physical harm to people in the home?
Additional observations:
1. The water main stubs up with PVC so using that as a GEC won't work. The water does stub into the house with copper but I think most of the plumbing is plastic. Do we still need to bond the water just before it goes into the house? My guess is yes.
2. There is no gas bond at the meter or hot water heater. How important is this for safety? I know it is a AHJ call.

Location of home is Sacramento, CA.

Many thanks,
Byron

You need to add a ground rod or 2. Around Sac you should be able to drive a rod with out too much trouble. Bonding is required also. Ufer may not be there, but look around for it neer the panel or the water. Good luck Rod

Thanks for your response. The issue with ground rods in Sacramento and Sacramento County is they are supplementary only. Their purpose is to act as a safety net when the electrician is using the water as the GEC. Many times a house will be replumbed from the street to the meter in PVC and nobody thinks about the effects on the electrical system.

I know many places you can use one or two 8' ground rods 6' or more apart for the GEC but that isn't accepted here. Sure, from time to time I'll find an oldtimer inspector that says it is fine.

Does Sac. have a written amendment to the Calif. Electic Code stating you can't use ground rods for electrodes, when there is no metallic in-ground water pipe and no UFER?

steve

I've asked that same question to inspectors all have said no but recently one said yes. The one thing Sac. county does is provide a sheet on how to build your own ufer. I'll see if I can post it.

Basically, if you don't have a water pipe or a ufer you are to make your own ufer.
Dig a trench 20' long, 1' deep, 1' wide. From the panel run a continous piece of #4 to the trench and it's length. Support the #4 3" above the dirt and then fill with concrete. Believe it or not there is a pre-concrete inspection required for the ufer.

[This message has been edited by bwise121 (edited 11-20-2006).]

Here you go: http://www.declareit.com/htdocs/ufer.pdf

There is an old rule of thumb that you are taught early on when doing commercial sound work. "when the ground is down, don't stick around" If said with the proper accent it rhymes. Electronic equipment can be very sensitive to this sorta thing. Many components actually use the ground as more than just a safety device. If I was the H.O., I would be mad as heck at whoever installed that.

Other than some protection from lightning, the lack of a grounding electrode will have no impact on the operation of electronic equipment, assuming that the main bonding jumper was installed.
Don

Grounding and _bonding_ can have a significant effect on things inside the house. Spend some time reading past threads in this section of the discussion board, or the Grounding and Bonding section of the Mike Holt board.

IMHO you should double check for proper bonding between any signal lines coming in to the entertainment center (eg. the CATV line) and the electrical system.

-Jon

There are very few electronic devices that care if the neutral is at or near ground potential. You can quite literally hook up any 120V device to two hots on a 110/63V Delta system- in working 8 years shipboard electronics, I have never seen a single item fail to work. If the neutral comes unbonded from ground, or has a poor bond to ground, the house will function just fine.

The danger is that metal that *should* be at ground potential is free to float up to dangerous voltages- and even this is tempered by the poco grounding the neutral at the pole. Proper grounding is a safety issue, not an operational one.

I tend to disagree about the ground having no affect on electronic equipment.

Often (but not always) in electronic equipment, the gound is used as a referenced 0 point for the rectified DC, especially when the power supply is creating a +/- DC supply. The AC is rectified, filtered, and, with a coulple of voltager regulators, resisters and capacitors, centered to a 0 point. The zero point is essential in reproducing a sinewave, and some systems still use the provided system ground to stabilize that zero. Even if only one of the devices in an A/V system use this as a reference, and it's not there, then you will see a problem.

Sure, my AA in Sound Engineering is 14 years old, but I'm pretty sure I'm still right on this.

Often (but not always) in electronic equipment, the gound is used as a referenced 0 point for the rectified DC, especially when the power supply is creating a +/- DC supply.

You seem to be confusing the equipment internal or chassis ground with the power line ground. One has nothing to do with the other, other than possibly causing ground loops. If the chassis grounds are interconnected and AC current is caused to flow through the line cord grounds and back around through the chassis grounds that can cause problems.

Exactly what sort of problem is the owner talking about with his electronic equipment?

-Hal

Thank you for all your responses. It seems there are some conflicting views.

Hal- the issue the owner is having is that his DVD player is "locking" up. Beutler Digital has replaced the DVD 4 times. In addition I believe they had to replace the Reciever once. Not sure why that was.

Thanks,
Byron

Zapped, the audio equipment shouldn't care what voltage the signal ground is with relation to the earth, just so long as it's all consistant between the equipment and all components are using it as a ground reference. That "ground" might be 120VDC from the actual earth, but you'd never know unless you happened to touch it...

If that ground happened to fluctuate with the AC signal though, as I'd expect to see with a bad earth ground, yeah, there would be an annoying hum.

[This message has been edited by SteveFehr (edited 11-21-2006).]

Just Googled Beutler Digital. Wow, talk about a jack of all trades. HVAC, central vac, home warranty service, structured wiring, security and entertainment systems. Makes me wonder if they know what they are talking about.

At any rate I really don't think there is any problem other than with the DVD player. Have they tried a different brand? These things are so cheap (yeah I know they charged him a bundle for it) that bugs are quite common. If tried other types and there are still problems then I would be suspicious.

-Hal

jon,
Give me some examples of problems in the house caused by a poor or missing grounding electrode system.
Don

Nope, not going to try

I was trying to emphasize the _bonding_ part of grounding and bonding.

I've personally seen the results of having the phone system lightning protector 'grounded' to one electrode, and the electrical system 'grounded' to another electrode, with no bond in between....system would probably have been better off with no grounding electrodes at all.

-Jon

Don, personal experience, I had enough voltage to knock the snot out of me from the frame of everything to my terazzo floor. Cause, bad ground electrode. Remember you still have voltage drop on the neutral, even if everything is tight. You need to be sure it is the same potential as the slab

gfretwell,
If you had that much voltage drop on the grounded conductor, then there was problem with the grounded conductor and a ground rod would not have solved the problem. If the grounding electrode was metal underground water piping system, then that grounding rod could have masked the symptoms of the problem, but would not have solved the problem. A ground rod would have masked the symptoms for only a few feet around the rod. If you had connected to the slab rebar, then that too would have masked the problem.
Don