Mar 21, 2024
What is the Resistance-to-Ground?
Fundamentally, the Resistance-to-Ground, also called Ground Resistance or Earth Resistance, is the resistance between your facility’s below-grade grounding electrode system and remote ground or...
Posts about ground grid
Feb 8, 2024
Beware of the NFPA 780 Simplified Lightning Risk Assessment
The de facto standard for Lightning Protection in the US is NFPA 780: Standard for the Installation of Lightning Protection Systems. Its Lightning Risk Assessment tool can be found in NFPA 780 Annex...
Sep 21, 2023
Everyone should watch this electrical grounding video
Practical Engineering recently posted a video on Youtube "Where Does Grounded Electricity Actually Go?" and we think everyone with an interest in electrical grounding, no matter the level, should...
Apr 22, 2022
Do GFCIs and RCDs need a Ground Wire to Work?
Before we begin, we should really do a quick review of the definition of “ground” or “earth” in electrical terms and what it really means to us. If you think back to your days in school, you may have...
Apr 13, 2022
Understanding Soil Resistivity Testing for Electrical...
Soil resistivity testing is the single most critical factor in electrical grounding design. This is true when discussing simple electrical design, to dedicated low-resistance grounding systems, or to...
Jan 31, 2022
What is the Best Definition for Ground or Earth?
Many people treat the NEC as if it’s the infallible word of some all-knowing electrical engineer (I wish it was). When in reality it’s written by committees that are full of political operatives,...
Oct 5, 2021
Top 3 Mistakes People Make with Grounding & Earthing...
The best way to protect people from electric shock and equipment from objectionable electrical damage, is to bond all exposed-conductive-parts together and ground/earth them to a single common...
Sep 29, 2021
How Many Terms for the Neutral Conductor does the NEC Need?
The National Electrical Code (NEC) is a vast and complex document. Even electrical engineers and electrical inspectors who spend most of their working hours inside the book will argue against anyone...
Aug 23, 2021
Managing Electrical Projects
Managing electrical projects these days is getting more and more complex. No longer do we have the days where we can simply design and install a basic electrical system without having to deal with...
Jun 28, 2021
Do Not Let Poor Grounding Ruin Your Fourth of July Pool...
A 14-year-old boy recently died in Texas after “stepping in a puddle” that had a submerged extension cord running through it. There had been heavy thunderstorms that week and the South Texas region...
May 25, 2021
Boeing 737 MAX Electrical Grounding Issues
Recently (May 4, 2021) a news article on grounding issues with the Boeing 737 MAX seemed to appear in most media outlets as a significant news story. Boeing did the right thing by suspending nearly a...
May 12, 2021
Can I tie the neutral and ground together?
Installing (or not installing) a neutral-to-ground bond in your electrical panel is an especially important decision that impacts the electrical safety of the entire facility and all the people that...
Feb 17, 2021
Does a Lightning Protection System Attract Lightning...
For the most part, lightning is comprised of free electrons that have been stored as static electricity in the clouds until those clouds can no longer hold the electrons. These free electrons want to...
Jan 27, 2021
What is the Sphere of Influence?
The Sphere of influence is the volume of soil throughout which the electrical potential rises to more than a small percentage of the potential rise of the ground electrode when that electrode...
Oct 28, 2020
Understanding Ground Test Well Details and Their Importance
Grounding Electrode Test WellsThe purpose of a ground test well is two-fold: to be able to quickly and easily measure resistance-to-ground of the grounding electrode and/or to measure point-to-point...
Sep 28, 2020
The Zone of Influence
The zone of influence is the volume of soil throughout which the electrical potential rises to more than a small percentage of the potential rise of the ground electrode, when that electrode...
Aug 18, 2020
Why are 94Hz, 105Hz, 111Hz, and 128Hz frequencies used for...
Numerous studies going back many decades have shown that ground resistance measurements should be conducted using a true Direct-Current (0 Hz) source with an Induced-Polarization (IP) capacity. In...
Aug 17, 2020
Rebar Grounding & Bonding: NEC Requirements Explained | E&S...
Jake Asked:What are the NEC Requirements for Grounding and Bonding Rebar?
Aug 9, 2020
When to bond neutral and ground? Should you make...
John asked:Should you make neutral-to-ground bonds in electrical panels?
Aug 5, 2020
What are some different types of grounding electrodes?
Grounding is the process of electrically connecting any metallic object to the earth by the way of an earth electrode system. The National Electric Code requires that the grounding electrodes be...
Jun 16, 2020
The NEC calls for use of Ground Fault Protection (GFP) type...
Nazhan Asked:The NEC calls for use of Ground Fault Protection (GFP) type for circuit breakers for services over 1000A, does this include buildings or just equipment?
May 13, 2020
Which ground or earthing rod should I use for my site?
Ground / Earthing rods (electrodes) are typically comprised of steel with a thin coating of copper or zinc (galvanized) to protect the steel from excessive corrosion. Copper-bonded ground rods are...
Jan 3, 2020
Why does my surge protection device say not to use it with...
Bill asked: I bought a Surge Protection Device (SPD) for my laptop that is working fine. However, in the fine print of the documentation it tells me that I should not use it with extension cords. Why...
Dec 18, 2019
How to Ground a Subpanel in a Detached Building or Garage?
Dan Asked:How do I run a 120 volt AC feeder from the main service panel (30 Amps) to a subpanel in a garage? Do I need to carry the ground wire in the feeder cable to the subpanel ground, which is...
Dec 6, 2019
What Is Electrical Grounding?
What Is Electrical Grounding? Electrical grounding or “Grounding” originally began as a safety measure used to help prevent people from accidentally coming in contact with electrical hazards. Think...
Nov 20, 2019
What is the purpose of the PVC sleeve in concrete grounding?
Doug asked:What is the purpose of PVC sleeves in concrete? Is there any reference material discussing ground wire installation methods in concrete?
Nov 14, 2019
Will applying salt around earthing electrodes help to...
Vighnesh asked:Our neutral to earth voltage is fluctuating from 2.5v to 4.5v. We have a separate neutral earthing for UPS and DG and separate body earthing. We also regularly applying salt for earth...
Nov 6, 2019
How Does One Lightning Strike Kill Multiple Animals?
Steve Asked: How does lightning kill multiple animals in a single strike?
Sep 30, 2019
What is Carbonaceous (Coke) Breeze and why was it banned?
Touri Asked:Can you please tell me which IEC article bans the use of carbonaceous backfills for earth electrodes?
Jul 9, 2019
What is the Best Soil Resistivity Testing Method?
Peter asked:What is the best soil resistivity testing method?
Jun 5, 2019
How To Do Electrical Grounding System Testing
The measurement of ground resistance for an earth electrode system is very important. It should be done when the electrode is first installed, and then at periodic intervals thereafter. This ensures...
May 8, 2019
How exactly are airplanes electrically grounded?
Michael Asked:How are airplanes electrically grounded? Is a lightning protection system (LPS) effective if it is not grounded? If you install a lightning rod that is not grounded, is it more or less...
Apr 23, 2019
Grounding of metal buildings
PJ Asked:Inspector requires grounding of metal building, I plan to use a rebar in slab to tie to metal frame in another place?
Mar 5, 2019
What is the difference between neutral and ground wires?
Raymond asked:What is the difference between neutral and ground wires?
Feb 5, 2019
Statement of Methodology for the NERC...
What are the data deliverables for the NERC Geomagnetically-Induced Currents (GIC) Project? BackgroundThe North American Electric Reliability Corporation (NERC) is a not-for-profit international...
Jan 23, 2019
Ground Rod Spacing: How Far Apart According to NEC?
Greg Asked:In order to place two grounding rods, what is the distance required by the NEC away from the electrical panel? And what is the distance they should be from each other (the rods)?
Jan 8, 2019
Can an insulated copper conductor be used for a ground grid?
Sourav Asked:A client is asking for an insulated copper conductor on a ground grid at a depth of 2’ from the grade level instead of bare copper due to corrosion issues. We are trying to model and...
Oct 30, 2018
How to calculate fault current in electrical substation...
Milan asked:How do I calculate the fault current an electrical substation grounding design? I am trying to understand how to design a substation grounding system and fault current is something I am...
Sep 17, 2018
How To Stop Copper Pipe Corrosion With Electrical Grounding?
Reid asked:We have a new house that we chose to plumb with copper. Can I stop copper pipe corrosion with electrical grounding?
Sep 6, 2018
What Is Soil Resistivity Testing?
Soil resistivity testing is the process of measuring a volume of soil to determine the conductivity of the soil. The resulting soil resistivity is expressed in ohm-meter or ohm-centimeter.
Aug 22, 2018
What are the lightning protection standards for lightning...
Kevin asked:What are the lightning protection standards for lightning down conductor installation?
Aug 16, 2018
Do I need a grounded conductor in my subpanel if all my...
Jack Asked:Do I need a grounded conductor (neutral) in my subpanel if all my loads are all 220v (i.e. 2-phase)?
Aug 3, 2018
Why separate the ground bar from the neutral bar in a...
Russ asked: How can I correctly separate the ground bar from the neutral bar in an electrical sub-panel?The Answer:
Jul 18, 2018
Is it ok to connect the lightning protection system to the...
Romeo Asked:Is it ok to connect the lightning protection system (LPS) to the main grounding system?
Jul 16, 2018
What is the safe maximum voltage at a railroad-highway...
Max Asked:What is the safe maximum voltage at a railroad-highway grade crossing during?
Jun 16, 2018
What Are Some Typical Electrical Grounding Testing...
Mike asked:What types of preventative maintenance electrical grounding testing procedures do you recommend for electrical grounding systems and how often?
May 11, 2018
Is a Step & Touch evaluation compulsory after installing a...
Nichole Asked:We are trying to put a swimming pool in, however, new rules are out that we have to get a Step and Touch evaluation done. Why?
Apr 6, 2018
Lightning Protection Down Conductor Size Guidelines
Benjamin Asked: What is the minimum size of a down conductor for lightning protection? What is the individual resistance and combine resistance of electrode? What is the resistance of grounding...
Mar 6, 2018
What Is Ground Potential Rise and Earth Potential Rise?
Ground Potential Rise (GPR) or Earth Potential Rise is a phenomenon that occurs when large amounts of electricity enter the earth. This is typically caused when substations or high-voltage towers...
Mar 3, 2018
Why use a bare conductor for below ground grounding instead...
Shyam asked:What is the reason for using a bare conductor for below ground grounding instead of an insulated conductor?
Mar 3, 2018
When is it necessary to put a disconnect switch in a...
Greg Asked:When is it necessary to put a disconnect switch in a residence with a 100, 200 amps? and where do you ground it to? a rod water pipes or just to the panel?
Feb 27, 2018
How can I test for an electrical current in water pipes?
Bob Asked:We have a new house that is all plastic water pipe from the city to the house, a small piece of copper pipe in the garage then PEX plastic pipe in the house. None of this is grounded. We...
Feb 7, 2018
When did the NEC Decide the Neutral and Ground Have to be...
Karl Asked:In what year did the NEC first require that the neutral and ground have to be separated in a sub panel?
Nov 11, 2017
The Mathematical Formula for Calculating Earth Resistance
Slamat Asked:What is the mathematical formula for calculating the resistance-to-ground of parallel electrodes?
Oct 26, 2017
Shared Neutral for 120/208V, 3-Phase, 4-Wire Feeders
Bob asked:How many ”hot” wires can a single neutral support?
Oct 20, 2017
How to get a grounding rod below 1ohm ground resistance?
Gajanan Asked:How to get a grounding rod below 1ohm ground resistance?
Sep 11, 2017
How we can reduce the voltage between the Neutral and...
Our Answer:The difference in voltage between the neutral to the ground at any point in your electrical system should be very low, typically something less than one (1) volt. This is easily measured...
Aug 17, 2017
GFCI Protection for Refrigerators: What You Need to Know
Max Asked:NEC now requires GFCI’s on refrigerators. Is there really a technical reason to put a GFCI on a refrigerator?
Aug 9, 2017
Applying salt around earthing electrodes to help resolve...
Vighnesh asked:Our neutral to earth voltage is fluctuating from 2.5v to 4.5v. We have a separate neutral earthing for UPS and DG and separate body earthing. We also regularly applying salt for earth...
Aug 3, 2017
Why bond the neutral and the ground wire in the main panel?
Jorge asked: Why should I be concerned about bonding the Neutral-to-Ground Bond in the main panel?The Answer:Neutral-to-ground bond is needed to properly operate the circuit breakers. Over Current...
Jun 9, 2017
How do I ground a metal building or metal warehouse with...
PJ Inquired:I bought a 40X24 Metal frame with metal sidings building. No Elec or plumb at present, maybe later. Inspector requires grounding Metal Building. 1×5/8”x8’cu clad steel rod ok tied to...
Jun 6, 2017
What is the Process for Installing a Lightning Protection...
Phase 1 – Conduct a Lighting Risk Assessment with a Rolling Sphere Analysis A Lighting Risk Assessment looks at a variety of factors involving the building, including the value of the property...
Apr 7, 2017
How do you calculate voltage variations across a ground...
Nilushka Asked: I’m interested in calculating the voltage variation of the soil, inside a mesh in a grounding grid. currently I have modeled a grounding grid including vertical rods using PSCAD...
Mar 15, 2017
Can all steel rebar be welded?
Jeff asked:Can I weld any steel rebar or are there specific grades to look for?Our Answer:Not all rebar can be welded, particularly with the exothermic welding process as it must be able to heat the...
Feb 2, 2017
What is Step and Touch Potential and Reducing Resistance To...
Step Potential Step potential is the step voltage between the feet of a person standing near an energized grounded object. It is equal to the difference in voltage, given by the voltage distribution...