Is a remote earth ground a good idea or a bad idea?

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tom baker

tom baker

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wwhitney said:
Say you have a house and a detached garage 10' away, supplied by a feeder from the house. The house service requires a GES. The garage requires a GES; say there are no other metallic paths between the two buildings.

So what is a scenario in which safety is greater with the garage GES in place and connected to the feeder EGC, rather than just having the single GES at the house service? E.g. a fault condition, with some postulated impedances of various paths, showing that the presence of the garage GES reduces some hazard from the fault. And which requires that the garage GES be located at the garage, rather than just being additional grounding electrodes that reduce the total GES to remote earth impedance.

If necessary, increase the 10' distance to 100' for a good example.

Cheers, Wayne
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Please explain what you mean by a fault
 
Joe.B

Joe.B

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Myths and legends? Reality? Or alternate reality? Fever dreams? Need say something because they're the expert? For example:

"this connection provides a safe pathway for any excess or misdirected electrical current"
"Without grounding, electrical charges that build up in the wiring can create serious damage"
"Grounding allows excess electrical to go into the ground where it dissipates harmlessly"
"so that whenever there is a voltage surge or fluctuation, the excessive current is directed toward the ground and not through you"
"Grounding is essential to reduce the fire risk of electricity in a small space made of flammable (wood) stuff"
"One of the most important reasons for grounding electrical currents is that it protects your appliances, your home and everyone in it from surges in electricity"
"Without a properly grounded electrical system, you are risking any appliances you have connected to your system being fried beyond repair"
"Grounding helps protect you and your home from the dangers of damaged circuits or electrical overloads"
"Proper grounding is an essential component of home electrical safety because excess energy needs to be directed somewhere"
"This safety feature helps protect you and your home from electrical mishaps by running part of the electrical load into the ground"

Top 10 results when I googled "Why do houses need to be grounded."
 
W

wwhitney

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Berkeley, CA
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Retired
tom baker said:
Wayne what do you mean by a fault?
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Anything other than normal operating conditions. Common ones I've heard of with respect to the GES being important are induced earth voltage from a nearby (not direct) lightning strike, or a high voltage aerial line falling on a low voltage aerial line, but I didn't want to restrict the scenarios. Let's assume the feeder from the house to the detached garage is underground, but the service to the house can be aerial.

Cheers, Wayne
 
romex jockey

romex jockey

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electrician
Sahib said:
If only auxiliary grounds and no bonding, damage due to passage of lightning current likely. If bonding also present, not likely because all points would rise to the same potential on passage of any lightning current and consequently no damaging discharges likely.
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iirc, that's the exact philosophy of all the nfpa 780 'lightning guys' Sahib

IE~ it's not so much that instantaneous surge, it's the dif in potential that can occur

kudos!
(y)
~RJ~
 
romex jockey

romex jockey

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Vermont
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electrician
wwhitney said:
Say you have a house and a detached garage 10' away, supplied by a feeder from the house. The house service requires a GES. The garage requires a GES; say there are no other metallic paths between the two buildings.

So what is a scenario in which safety is greater with the garage GES in place and connected to the feeder EGC, rather than just having the single GES at the house service? E.g. a fault condition, with some postulated impedances of various paths, showing that the presence of the garage GES reduces some hazard from the fault. And which requires that the garage GES be located at the garage, rather than just being additional grounding electrodes that reduce the total GES to remote earth impedance.

If necessary, increase the 10' distance to 100' for a good example.

Cheers, Wayne
Click to expand...
welp , now we're onto GES, which serves a different purpose that a GEC Wayne. I'm sure i'm preaching to the choir saying this , but plz cut me some slack as so many are confused......what would be an appreciable dif in 10 Vs 100' ? Mag Trip comes to mind.......~RJ~
 
Sahib

Sahib

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India
One interesting recommendation is if the distance between two grounded objects is more than a specified limit, they need not be bonded together.
 
Sahib

Sahib

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Location
India
Joe.B said:
Myths and legends? Reality? Or alternate reality? Fever dreams? Need say something because they're the expert? For example:

"this connection provides a safe pathway for any excess or misdirected electrical current"
"Without grounding, electrical charges that build up in the wiring can create serious damage"
"Grounding allows excess electrical to go into the ground where it dissipates harmlessly"
"so that whenever there is a voltage surge or fluctuation, the excessive current is directed toward the ground and not through you"
"Grounding is essential to reduce the fire risk of electricity in a small space made of flammable (wood) stuff"
"One of the most important reasons for grounding electrical currents is that it protects your appliances, your home and everyone in it from surges in electricity"
"Without a properly grounded electrical system, you are risking any appliances you have connected to your system being fried beyond repair"
"Grounding helps protect you and your home from the dangers of damaged circuits or electrical overloads"
"Proper grounding is an essential component of home electrical safety because excess energy needs to be directed somewhere"
"This safety feature helps protect you and your home from electrical mishaps by running part of the electrical load into the ground"

Top 10 results when I googled "Why do houses need to be grounded."
Click to expand...
You may make a more refined search for the following question:
During the operation of a protective device on a ground fault, anyone touching the circuit is likely to get a shock depending on ground resistance. How to keep ground resistance optimum to avoid shock or electrocution?
 
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