I’m doing some remodel work and need to relocate the ground cable and rod coming out of an existing 200A main panel. The ground cable now is inside steel conduit, 3/8″ diameter, braided, not sure how many conductors. It goes from the panel ground bus to a ground rod in front of the panel, makes a continious loop then goes about 15 feet to a copper water pipe (in the dirt) main where it terminates. It is one continious cable. So, I want to move the ground rod to make some space for foundation vent. When I remove the rod and replace the ground cable with one a few feet longer, is there any safey hazard with the box temporarily having no ground connection to the earth rod and the copper water main ? The neutral and ground are common on the utility pole, right ?
thanks !
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You need to, at a minimum, establish the new ground connection before breaking the old, or at least install a "temporary temporary" ground while making the switch. It is quite unsafe to rely on the pole ground, even for a few minutes.
Keep in mind that "legally" the ground wire must be continuous, with no splices. In practice it's probably reasonably safe to use a spliced cable for a short period of time, but you need to be sure the splices are good (double up the clamps), and take care that they don't get pulled apart in your work.
In my experience...
DanH wrote:
You need to, at a minimum, establish the new ground connection before breaking the old, or at least install a "temporary temporary" ground while making the switch. It is quite unsafe to rely on the pole ground, even for a few minutes.While there is a slight chance there is current flowing on the grounding electrode conductor (GEC), it is NOT imo "quite unsafe" to do this. You are NOT "relying" on any pole ground for anything critical. A home can run without any grounding electrodes at all and still be safe under normal conditions. That said, I would not go anywhere near it in a lightning storm.
To ensure there is no issue, within your own house, turn off the main breaker. Then make the change.
DanH wrote:Keep in mind that "legally" the ground wire must be continuous, with no splices. In practice it's probably reasonably safe to use a spliced cable for a short period of time, but you need to be sure the splices are good (double up the clamps), and take care that they don't get pulled apart in your work.
It is a requirement to have the GEC continuous to the first electrode. There is NO requirement to have it unbroken to any additional electrodes.
It seems to me that all you would have to do to insure safety is simply switch off the main breakers to the house. No power thus no danger. Do the work, reestablish the ground, and re-energize. Having the electric power off for a short time isn't all that great a disruption.
That doesn't necessarily assure safety.
Until you turn off the power to the panel, that ground wire is "hot." If you're using ANY electricity, there's some of it flowing through that ground wire. So, step #1 is to kill the power.
OK, so you've relocated the ground rod. What's your next move?
The wire from the panel to the ground rod must be continuous and not have any splices. Nor can the 'water bond' - the wire to the pipe - have any splices. You're going to have to re-run the wire. Please note that it's OK to land this new wire on the ground rod; you don't need everything to use the same wire. You can even run the water bond to the panel, instead of the rod.
Even with the panel disconnected, there's a non-trivial hazard from a possibly improperly grounded pole transformer (which seems to happen with apalling regularity). Ie, the "neutral" wire from the transformer could be "hot", due to leakage in the transformer.
No
DanH wrote:
Even with the panel disconnected, there's a non-trivial hazard from a possibly improperly grounded pole transformer (which seems to happen with apalling regularity). Ie, the "neutral" wire from the transformer could be "hot", due to leakage in the transformer.
What you are describing is like saying every time an electricina makes up a GEC it is a near death experience. This is not at all the case.
How is it done safely for the first time if this is such a critical situation??
Not true
Amish Electrician wrote:
Until you turn off the power to the panel, that ground wire is "hot." If you're using ANY electricity, there's some of it flowing through that ground wire. So, step #1 is to kill the power.
Under normal conditions this is absolutely UNTRUE. The GEC is most definitely NOT "hot".
Mower snagged the ground wire on the pole and broke it. With the house ground disconnected, any leakage current from transformer primary to secondary will be present on the neutral conductor. Are you that confident that there's less than 60ma leakage current?
Changing ground to panel
for a 200A service #4 copper min to jump and go before the main water shut off to the other side of the water meter. #8 copper min to go to the ground rods (2) they must be a min of 6' apart unless you get a reading of 25 ohms you only need 1.
Like every one else says shut off the main breaker and leave the existing ground and install a new one then remove the old one. There is a chance of a bad ground at the pole and if removed could be power on the ground wire and if so and not shutting off the main breaker is a chance of things blowing up in the house because of no ground and only being 220 volts
I am a licensed electrician in 2 states