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.
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
#72161 - 11/20/0607:11 PMRe: What harm in no grounding electrode?
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.
#72162 - 11/20/0610:12 PMRe: What harm in no grounding electrode?
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).]
#72164 - 11/20/0611:58 PMRe: What harm in no grounding electrode?
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.
#72166 - 11/21/0606:52 AMRe: What harm in no grounding electrode?
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.
#72168 - 11/21/0612:04 PMRe: What harm in no grounding electrode?
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.