Propeller Head Plaza Technical and scientific discussion of amps, cables and other topics.

---

[ Follow Ups ] Thread: [ Display  All  Email ] [ Propeller Head Plaza ]

---

[ Alert Moderator ]

---

Re: Noisey Earthground????

Posted by jea48 (A) on August 30, 2005 at 18:50:30

In Reply to: Re: Noisey Earthground???? posted by Jacques on August 29, 2005 at 04:26:27:

It is mandatory to have a special copper or stainless steel rod (about 1m
long, to which the main entrance box is connected via heavy gauge copper
wire with a maximum of 2 90° turns. Earth resistance at the rods is to be checked
for receipt of a new house, or when selling it (depends on the state regulations).
A max of 25 ohms is allowed. If greater, a second rod shall be used with
conditions"
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

>"It is mandatory to have a special copper or stainless steel rod (about 1m"
==============

1m ?? 39in.? The soil must really be moist in France.
=================================================================

Note: All of my responses will be for the USA, Nec 2005..........

At least one Supplemental ground rod is required, at least 5/8" x 8' driven into the earth in addition to the main incoming domestic water service line. Providing it is metallic. By the way homes have had copper water lines since 50s. Most Power Utility Companies require two Supplemental ground rods to be driven for grounding electrodes in addition to the incoming domestic water line. A grounding electrode conductor is run from an approved grounding water pipe clamp, connected to the incoming water line. And the other end is terminated on the neutral/ground bar of the main electrical service panel. A second grounding electrode conductor has one end terminated on the neutral/ground bar and the other end connects to one of the supplemental ground rods, with an approved ground clamp, the grounding electrode conductor must be continuous, unbroken, and connected to the second ground rod with an approved ground clamp.
Back at the main service panel as you know is where the incoming service entrance neutral is bonded to ground. And also as you know all branch circuit equipment grounding conductors will terminate on the neutral/ground bar. A star ground.
==============================================

>"A max of 25 ohms is allowed. If greater, a second rod shall be used with conditions"
>>>>>>>>>>

NEC requires the same. Where is your 25 ohm reference taken from?
==================================

>"The rationale in non using the water pipes is (1) to avoid losing workers' life
in case of a direct lightning stroke onto a house without a earthing rod.
If the soil is very resistive (rock or dry sand), the stroke can run on
long distances and kill remote workers."
>>>>>>>>>>

I have never heard of that happening here in the U.S.

======================

>"Also, problem of liability: you installed lightning protection
in your main box, got a direct lightning stroke but got all your cherished
audiophile equipment cooked black smoky.
Who's liable for the insurance? You (you should unplug your valuable assets in
case of a storm), the protector manufacturer,Also, problem of liability: you installed lightning protection
in your main box, got a direct lightning stroke but got all your cherished
audiophile equipment cooked black smoky.
Who's liable for the insurance? You (you should unplug your valuable assets in
case of a storm), the protector manufacturer, the water company who bared
the pipes in the street for fixing a leak _this_morning, the cherished
equiment manufacturer (you ;-), God? Not easy to unscrumble"
>>>>>
"the pipes in the street for fixing a leak _this_morning, the cherished
equiment manufacturer (you ;-), God? Not easy to unscrumble"
>>>>>>>>>>>>>>

As per NEC an under ground water pipe 20ft in length is considered a grounding electrode. Also do not forget the minimum supplemental ground rod.
=====================================================

>"Another difference in these matters is that in EU (maybe not in whole UK??)
distribution is done this way: 20KV triphase goes to the Delta primary of a
triphase transformer (no monophase xformer like in america, not only the
US), its secondary is Y, and the center of the Y is the neutral. At the
transformer premises (would it be a cabin, a room or just a pole), the
center of the Y is connected to the earth through a metal rod. Then the
distribution company makes its phase balance between customers, most of
residential customerjust use a 230V monophase. Only 3 phases and a neutral
are distributed for 230V"
>>>>>>

>"triphase transformer (no monophase xformer like in america, not only the
US), its secondary is Y, and the center of the Y is the neutral."
>>>>>>>>>

Not in residential single family dwelling housing units, a house. The utility transformer secondary that feeds a house/s is a single phase with a center tap mid way in the secondary winding, a split phase system. 120/240 volt 3wire single phase grounded AC system. The neutral will be bonded to ground at the main service panel. Oh by the way at the power companies utiliy transformer the utility company drives a ground rod and bonds the Hi voltage grounded neutral conductor and the secondary neutral together and exstends a ground wire to the driven ground rod. More lightning protection. The United States probably has more driven ground rods than the rest of the World combined.
============================================================

>"At the customer mains box, there is NO connection between the neutral and
his/her earth (rod as explained above). Both mains, hot and neutral, stay
floating as seen by any equipment connected to them. Very diffrent from the
american way.
advantages and drawbacks of the european vs american solution :
EU: as the mains shall be floating, it's easy to check out: just
disconnect the mains breaker, and check with an ohmmeter you got kiloohms
between any AC wire and earth."
>>>>>>>>>>>>>

We use this type of a floating system here in the U.S. in Hospital surgery rooms, Cath Lab rooms, and in some Xray rooms. NEC requires ground leakage detection where as it must have a light and audible alarm system. The panel must have a light and alarm on it, and the room in which the branch cicuits are installed in must have a remote light and alarm unit. If any leakage of an ungrounded conductor above 5ma to ground is detected, the light comes on and the alarm sounds.
How do you check for leakage to ground? Say in a kitchen and that grounded sink?...
=======================================
Audio ground loops, I have never experienced the problem My audio branch circuits are as per NEC, but not minimum as per NEC.

This post is made possible by the generous support of people like you and our sponsors:

Atma-Sphere Music Systems, Inc.

---

[ Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2025, Audio Asylum, all rights reserved ]

---

[ General ] [ Speakers ] [ Tubes ] [ Vinyl ] [ Digital ] [ Hi-Rez ] [ Video Asylum ] [ Cables ] [ Tweaks/DIY ] [ Music ] [ Films ]

---