Help
  • Explore Community
  • Get Started
  • Ask the Community
  • How-To & Best Practices
  • Contact Support
Notifications
Login / Register
Community
Community
Notifications
close
  • Forums
  • Knowledge Center
  • Events & Webinars
  • Ideas
  • Blogs
Help
Help
  • Explore Community
  • Get Started
  • Ask the Community
  • How-To & Best Practices
  • Contact Support
Login / Register
Sustainability
Sustainability

Ask Me About Webinar: Data Center Assets - Modeling, Cooling, and CFD Simulation
Join our 30-minute expert session on July 10, 2025 (9:00 AM & 5:00 PM CET), to explore Digital Twins, cooling simulations, and IT infrastructure modeling. Learn how to boost resiliency and plan power capacity effectively. Register now to secure your spot!

Earth Ground

APC UPS for Home and Office Forum

Support forum to share knowledge about installation and configuration of APC offers including Home Office UPS, Surge Protectors, UTS, software and services.

cancel
Turn on suggestions
Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type.
Showing results for 
Show  only  | Search instead for 
Did you mean: 
  • Home
  • Schneider Electric Community
  • APC UPS, Critical Power, Cooling and Racks
  • APC UPS for Home and Office Forum
  • Earth Ground
Options
  • Mark Topic as New
  • Mark Topic as Read
  • Float this Topic for Current User
  • Bookmark
  • Subscribe
  • Mute
  • Printer Friendly Page
Invite a Co-worker
Send a co-worker an invite to the portal.Just enter their email address and we'll connect them to register. After joining, they will belong to the same company.
You have entered an invalid email address. Please re-enter the email address.
This co-worker has already been invited to the Exchange portal. Please invite another co-worker.
Please enter email address
Send Invite Cancel
Invitation Sent
Your invitation was sent.Thanks for sharing Exchange with your co-worker.
Send New Invite Close
Top Experts
User Count
BillP
Administrator BillP Administrator
2151
Teken
Spock Teken
101
voidstar_apc
Janeway voidstar_apc
83
View All

Invite a Colleague

Found this content useful? Share it with a Colleague!

Invite a Colleague Invite
Solved Go to Solution
Back to APC UPS for Home and Office Forum
Solved
Anonymous user
Not applicable

Posted: ‎2021-06-29 06:15 PM . Last Modified: ‎2024-03-21 03:48 AM

0 Likes
3
1726
  • Mark as New
  • Bookmark
  • Subscribe
  • Mute
  • Permalink
  • Print
  • Email to a Friend
  • Report Inappropriate Content

Link copied. Please paste this link to share this article on your social media post.

Posted: ‎2021-06-29 06:15 PM . Last Modified: ‎2024-03-21 03:48 AM

Earth Ground

I read an excellent APC article (White Paper #21) about neutral and ground. It was not explained though, exactly why the neutral is actually connected to the earth. The explination given for the safety of having exposed metal equipment connected with a ground wire that is ultimately connected to the neutral at the service panel does not explain the reason for an earth connection. If a hot conductor touched the metal case of equipment which has a ground wire, it would create a short circuit and trip the breaker, regardless of a physical connection to the earth. So why do we have these "earth" connections? It seems like all they do is offer a path back to neutral if a person is touching earth and an exposed hot connector. Where is the added safety in that?

Labels
  • Labels:
  • Universal Transfer Switch
Reply

Link copied. Please paste this link to share this article on your social media post.

Contact Support
  • All forum topics
  • Previous Topic
  • Next Topic

Accepted Solutions
BillP
Administrator BillP Administrator
Administrator

Posted: ‎2021-06-29 06:15 PM . Last Modified: ‎2024-03-21 03:48 AM

0 Likes
0
1726
  • Mark as New
  • Bookmark
  • Subscribe
  • Mute
  • Permalink
  • Print
  • Email to a Friend
  • Report Inappropriate Content

Link copied. Please paste this link to share this article on your social media post.

Posted: ‎2021-06-29 06:15 PM . Last Modified: ‎2024-03-21 03:48 AM

The earth ground is not inherently negative or positive. It is simply that there can be potential between any 2 points in ground. When we are dealing with power coming from AC lines, hot is not positive. Voltage on an AC line cycles positive to negative and back again 60 times per second. No, I don't believe a battery would not discharge itself however the generation and distribution of AC voltage differs quite a bit from a stand-alone battery.

Ground is not required to regulate the voltage between the hots or from hot to neutral. You however may be touching ground when holding on to a rack or standing on the floor. This is the safety aspect. If there is a short on a piece of equipment, the outer case (if it is metal) could become energised. Since the outter case is grounded, the power will simply pass to ground. There is basically a short circuit now from your device's metal case to ground. That short is the path of least resistance and current will flow that way.

If the system was not grounded, you would create the path of least resistance if you touched the outer case.

As for the power company using ground to regulate the voltage between the 2 hot legs, it does not. I'm sorry if I was unclear about that. Transformers are used to create the voltages that come into your house and the neutral. As long as the power does not fluctuate and everything is as it is supposed to be, there will be 120 volts from each hot to neutral and 240 from one hot to the other.

The neutral starts there and does not travel from the generation facility. When you see power lines with 3 wires, you are actually seeing 3 hot legs that are 120 degrees out of phase.

There is always voltage present in the Earth however. The Earth is also a conductor. The simple fact is that whenever there is a potential difference between any 2 conductors, it is possible for current to flow.

It looks like you're looking more into the theoretical aspect of grounding rather than requirements or electrical codes. If you're really into the theory of it, perhaps you could read up on Nikola Tesla. I believe he theorized (among many other things) using the Earth itself as a power source. No generators needed. Simply using the differences in potential that exist between 2 points in ground as an electrical source.
There's a lot of info on him here:
http://en.wikipedia.org/wiki/Nikola_Tesla

Here are a few other links that I've found that seem to go into grounding in much more depth. Maybe they can be of help:
http://www.pfeiffereng.com/Principals%2520of%2520Electrical%2520Grounding.pdf
http://www.epanorama.net/documents/groundloop/why_grounding.html

See Answer In Context

Reply

Link copied. Please paste this link to share this article on your social media post.

Contact Support
Replies 3
BillP
Administrator BillP Administrator
Administrator

Posted: ‎2021-06-29 06:15 PM . Last Modified: ‎2024-03-21 03:48 AM

0 Likes
0
1726
  • Mark as New
  • Bookmark
  • Subscribe
  • Mute
  • Permalink
  • Print
  • Email to a Friend
  • Report Inappropriate Content

Link copied. Please paste this link to share this article on your social media post.

Posted: ‎2021-06-29 06:15 PM . Last Modified: ‎2024-03-21 03:48 AM

No matter if you have a neutral to ground bond or not, if you touch ground and a hot leg at the same time, you're gonna get zapped. If there was no neutral to ground bond, there's also the potential that you'd get zapped if you touched neutral as well. With the bond, that won't happen (when touching neutral anyway).

The power companies can only regulate the power between 2 hot legs. A transformer will then give you the neutral. In a home environment, that's simply a middle point on the main 240 volt power and it gives you (2) 120 volt sources (each hot to neutral).

With the neutral to ground bond, that also ensures that you have (2) hot legs at 120 volts with respect to ground as well. Without that bond, the voltage from neutral to ground can not be regulated and in turn, the voltage between hot and ground would not be regulated.

Between any 2 points on ground, there is a chance for voltage. The farther away the 2 points being measured, the more potential there is. If your utility pole/transformer is grounded, it's close to your house, and you measure voltages at your electrical service entrance, you'll probably see only a little voltage from neutral to ground. The farther away you are from that transformer, the more voltage you're likely to see.

Most electrical equipment can deal with a few extra volts. Many of todays electronic equipment however can be very sensitive to voltages between neutral and ground especially.

Reply

Link copied. Please paste this link to share this article on your social media post.

Contact Support
Anonymous user
Not applicable

Posted: ‎2021-06-29 06:15 PM . Last Modified: ‎2024-03-21 03:48 AM

0 Likes
0
1726
  • Mark as New
  • Bookmark
  • Subscribe
  • Mute
  • Permalink
  • Print
  • Email to a Friend
  • Report Inappropriate Content

Link copied. Please paste this link to share this article on your social media post.

Posted: ‎2021-06-29 06:15 PM . Last Modified: ‎2024-03-21 03:48 AM

I read an excellent APC article (White Paper #21) about neutral and ground. It was not explained though, exactly why the neutral is actually connected to the earth. The explination given for the safety of having exposed metal equipment connected with a ground wire that is ultimately connected to the neutral at the service panel does not explain the reason for an earth connection. If a hot conductor touched the metal case of equipment which has a ground wire, it would create a short circuit and trip the breaker, regardless of a physical connection to the earth. So why do we have these "earth" connections? It seems like all they do is offer a path back to neutral if a person is touching earth and an exposed hot connector. Where is the added safety in that?

Reply

Link copied. Please paste this link to share this article on your social media post.

Contact Support
BillP
Administrator BillP Administrator
Administrator

Posted: ‎2021-06-29 06:15 PM . Last Modified: ‎2024-03-21 03:48 AM

0 Likes
0
1727
  • Mark as New
  • Bookmark
  • Subscribe
  • Mute
  • Permalink
  • Print
  • Email to a Friend
  • Report Inappropriate Content

Link copied. Please paste this link to share this article on your social media post.

Posted: ‎2021-06-29 06:15 PM . Last Modified: ‎2024-03-21 03:48 AM

The earth ground is not inherently negative or positive. It is simply that there can be potential between any 2 points in ground. When we are dealing with power coming from AC lines, hot is not positive. Voltage on an AC line cycles positive to negative and back again 60 times per second. No, I don't believe a battery would not discharge itself however the generation and distribution of AC voltage differs quite a bit from a stand-alone battery.

Ground is not required to regulate the voltage between the hots or from hot to neutral. You however may be touching ground when holding on to a rack or standing on the floor. This is the safety aspect. If there is a short on a piece of equipment, the outer case (if it is metal) could become energised. Since the outter case is grounded, the power will simply pass to ground. There is basically a short circuit now from your device's metal case to ground. That short is the path of least resistance and current will flow that way.

If the system was not grounded, you would create the path of least resistance if you touched the outer case.

As for the power company using ground to regulate the voltage between the 2 hot legs, it does not. I'm sorry if I was unclear about that. Transformers are used to create the voltages that come into your house and the neutral. As long as the power does not fluctuate and everything is as it is supposed to be, there will be 120 volts from each hot to neutral and 240 from one hot to the other.

The neutral starts there and does not travel from the generation facility. When you see power lines with 3 wires, you are actually seeing 3 hot legs that are 120 degrees out of phase.

There is always voltage present in the Earth however. The Earth is also a conductor. The simple fact is that whenever there is a potential difference between any 2 conductors, it is possible for current to flow.

It looks like you're looking more into the theoretical aspect of grounding rather than requirements or electrical codes. If you're really into the theory of it, perhaps you could read up on Nikola Tesla. I believe he theorized (among many other things) using the Earth itself as a power source. No generators needed. Simply using the differences in potential that exist between 2 points in ground as an electrical source.
There's a lot of info on him here:
http://en.wikipedia.org/wiki/Nikola_Tesla

Here are a few other links that I've found that seem to go into grounding in much more depth. Maybe they can be of help:
http://www.pfeiffereng.com/Principals%2520of%2520Electrical%2520Grounding.pdf
http://www.epanorama.net/documents/groundloop/why_grounding.html

Reply

Link copied. Please paste this link to share this article on your social media post.

Contact Support
Preview Exit Preview

never-displayed

You must be signed in to add attachments

never-displayed

 
To The Top!

Forums

  • APC UPS Data Center Backup Solutions
  • EcoStruxure IT
  • EcoStruxure Geo SCADA Expert
  • Metering & Power Quality
  • Schneider Electric Wiser

Knowledge Center

Events & webinars

Ideas

Blogs

Get Started

  • Ask the Community
  • Community Guidelines
  • Community User Guide
  • How-To & Best Practice
  • Experts Leaderboard
  • Contact Support
Brand-Logo
Subscribing is a smart move!
You can subscribe to this board after you log in or create your free account.
Forum-Icon

Create your free account or log in to subscribe to the board - and gain access to more than 10,000+ support articles along with insights from experts and peers.

Register today for FREE

Register Now

Already have an account? Login

Terms & Conditions Privacy Notice Change your Cookie Settings © 2025 Schneider Electric

This is a heading

With achievable small steps, users progress and continually feel satisfaction in task accomplishment.

Usetiful Onboarding Checklist remembers the progress of every user, allowing them to take bite-sized journeys and continue where they left.

of