Electrical ground system inspection procedures & checklists.

This document discusses procedures the inspection of the grounding system components of a building electrical system when performed by trained building inspection professionals, home inspectors, electrical inspectors, and electricians.

Guide to Inspecting Electrical Service Grounding Equipment for Defects

Here we define electrical ground, grounding, bonding, and earthing terms and explain why there are important differences among these words.

Photo: a loose and therefore ineffective and unsafe electrical ground wire at the grounding electrode.

“Grounding”, article 250 in the NEC, is probably one of the most difficult of the often used articles. In 2005 article 250 became “Grounding and bonding”. In the 2008 NEC there has been a major revision in language, and phrases like “shall be grounded” have changed to “shall be connected to an equipment grounding conductor.”

These questions & answers about electrical ground systems at buildings were posted originally at ELECTRICAL GROUNDING in OLDER HOMES - be sure to see that article.

Watch out: improper electrical grounding at a building can cause or contribute to fire, electrical shock, even death. If you are not qualified / trained in working safely with electrical wiring, leave any suspect electrical circuits off and ask for help from a licensed electrician.

On 2018-01-09 by (mod) - electrical current found on gas piping

Kimberly

Watch out: you are describing a potentially fatal shock or fire or even explosion hazard.

Adding grounding electrodes won't correct an incorrect electrical connection somewhere in your system. I can't know where that mistake lies, though obviously somewhere we have a current-carrying wire connected to the gas piping.

You could have a neutral - to - ground short circuit or some other problem in your wiring system.
You might try turning off electrical circuits one by one until you see the current on the gas line disappear. When you find it, leave that circuit OFF

At any rate, I would ask for help from a licensed electrician.

On 2018-01-09 by Kimberly

So I put rods in the ground to try to get ground but electricity is still coming through gas line... help??

On 2017-12-16 by (mod) - ground plug is always hot

Don

If the grounding conductor in whatever you're plugging in is carrying current and thus heating up, something is very unsafe, risking fire or electrocution (death).

I would leave whatever that is unplugged.

If plugging in anything at that specific wall receptacle makes the ground pin on the plug get hot then something else is wrong - in the circuit and it's an unsafe circuit. Switch the circuit off and ask for help from a licensed electrician who can find and fix the fault.

On 2017-12-15 by don

the ground on the wall plug is hot all the tine

On 2017-12-14 by (mod) - Some codes do not permit splicing in the grounding electrode conductor

Ground

Some codes do not permit splicing in the grounding electrode conductor but I have certainly seen that permitted by local authorities.

Grounding electrode conductors are not normally seen running inside conduit. It is not required. IF you run the grounding electrode inside of metal conduit then that conduit has to be properly grounded - that is, it must be electrically continuous from the point of attachment to the electrical panel.

I often see the electrode conductor strapped to existing conduit along part of its route.

I didn't understand your earlier query about vice and lose knot.

On 2017-12-13 by Ground wire to meter

Can the ground wire to them meter be spliced and can it not be in conduit

On 2017-12-13 by Ground wire to the meter

Can this wire between vice and loose knot in conduit or attached to the wall

On 2017-03-06 by (mod) -

Charlotte,
A we noted on another page at another of your comments, you need a local, licensed electrician to survey the wiring for safety and to do what repairs are needed. This isn't something a homeowner can fix by e-text advice.

On 2017-03-05 by charlotte

need tp replace main wire under mobule to have electric turned on edison says

On 2017-01-02 by (mod) -

Joseph:

I agree that the advice is a bit broad, and honestly, I can't explain the whole house grounding system in a brief e-text. The article above does a better job telling you what grounding is for and why it's important for safety.

Since the electrical ground system is not normally doing anything - that is it's not participating in the delivery of electrical current to your light fixtures nor participating in the return path of the current to the electrical panel, the problem is most-likely something else.

Perhaps your contractor friend is thinking that there are stray electrical currents in the ground system - that's something your electrician can check using the proper test equipment.

A licensed electrician might check for
- loose electrical connections in the lighting circuit or panel.

Recessed lights can also have a short bulb life if they're running hot. That might be due to using over-sized bulbs or due to insulating over a light that is not rated to be insulated.

I'll bet a beer that if you swap out your traditional incandescent light bulbs for newer and more expensive LED type bulbs you'll get the same or more light at lower electricity consumption (watts), cooler light operation, and longer bulb life.

Search InspectApedia for LED LIGHT BULBS to see more information.

On 2017-01-02 by joseph h caro

We have been in our house approx. 10 years, finally a pattern arose of being unable to have a light bulb servive for any length of time. We have some recessed lighting and each room has a fan with 4 lights attached. both require bulb change often. A contractor friend stated, chk your house grounding. I don't have a clue, what are the code requirements, what constituted a proper grounding system?

On 2016-11-29 by (mod) -

Yes, a disconnected local ground could cause fire or death as aneeded important safety feature is disconnected. In addition to making the proper connection and electrician might ask how c an

On 2016-11-29 by smarshall

Hello.i was out the front of my rental property this morning and noticed that my main earth conductor has been seperated from the i think earth rod.i assume this un attached wire could be dangerous?if so how bad? If not is it as simple as feeding it back thru and tightening the nut? Also this is directly under my main circuit boad and gas meter could this cause faulty readings?

On 2016-10-12 by John Koktowski

I installed a sub-panel in my garage along with two grounding bars. the grounding is connected to the neutral bar so it is isolated from the panel. what is best way to run the grounding wire into the box so it does not come in contact with the box itself??

On 2016-10-06 by Kevin

I have a 50 amp travel trailer sub panel that is over 200 feet from the meter base and main disconnect panel. The run was made without running a ground wire from the main box (previous owner) with the neutral and two hot wires. I anticipate have to put ground rods in at the box and ground the box. Do I need to bond the box to the ground?

On 2016-06-05 by (mod) -

John and Cathy

A common older methods of providing an electrical ground at homes was connection of the grounding conductor system in the panel to a buried metal water pipe; today most codes want two grounds; there are separate advantages to grounding the plumbing system (pipes, metal sinks, &c): someone knocks a toaster into the sink; the path through metal piping to earth allows current to flow safely to earth while tripping the breaker;

On 2016-06-05 by Cathy

The outside water tap is situated against the electrical mast is this allowed.

On 2016-04-26 by John

can a house be grounded to the water systemyes

On 2016-04-05 by (mod) -

Rey: There are ground bonding clamps specifically designed for copper water or drain piping. You should select a clamp that fits the range of pipe size, and tighten it snugly. You'd be more at risk of crushing thin-wall copper such as is used in heating baseboards.

On 2016-04-04 by rey

can a clamp be used on a copper pipe?. I was told it was not allowed because it would crush the pipe

On 2016-02-29 by (mod) -

CMCP

Thank you for the helpful comment about bonding gas piping.

On 2016-02-28 by (mod) -

Dwayne,

WATCH OUT: this work is normally performed by a licensed electrician. Making a mistake can burn down the house or kill someone. At the very least, if you are permitted to do your own wiring where you live, be sure that you obtain the required permit, inspection, and approval of the work.

Normally in the main electrical panel (NOT in a sub panel) the panel box is grounded in common with the neutral bus by a grounding conductor bond to one or two (depending on local regulations) local grounds such as a driven electrode and incoming metal water pipe or to two driven electrodes.

I can only GUESS at what you are seeing in the panel, perhaps a screw for bonding the panel enclosure to the system ground.

On 2016-02-28 by Dwayne

Also the house has no gas and water lines arereplaced with pex but water heater is bonded

On 2016-02-28 by Dwayne

I replaced my old panel 100amp with a squareD 200 amp panel. My question is from the ground rod I attach # 4 bare wire and run it to where? There is a large green screw located at the top just below the 3 service wires and above the breakers . I assumed that i could just run the number 4 wire and atach it directly to the panel at the bottom. But what is the big green screw for? It looks like theres a prefab hole behind the screw and the size of bare # 4 wire. Please help. Thank you D. Cowart

On 2016-02-28 by cmcp

in the section on "Gas Piping May Need to Be Bonded to the Electrical Ground System" it should noted that the bonding is after (the house piping side)of the dielectric, isolating or insulating union in the gas line. If it is on the utility of supply side the of the union the underground supply pipe may experience galvanic corrosion.

On 2016-01-26 by (mod)

Hi Lucy

See LIGHT SWITCH WIRING DETAILS

On 2016-01-26 by lucy

Hi there,

I have a new build home (2years old) my husband went to install dimmer light switches at the weekend and realizd that the switches are not grounded. I am from the UK and that wouldn't even pass inspection over there, is that the same case in Canada?

Thanks,
Lucy

On 2015-10-18 by Lori albrecht

Can my outdoor water faucet be just in fort or does it have to be encased in cement? 1974 mobile home?

On 2015-09-14 by (mod) -

Roger,

I cannot give an authoritative explanation without an on-site visit to find all of the factors involved but I suspect that the circuit breaker is defective; can you tell me the electrical panel brand and model; or use the email found at the page bottom CONTACT link to send me photos of the system and the components involved.

Generally we ground plumbing specifically so that if a live wire contacts the plumbing system current will flow to ground and trip the breaker or blow the fuse. If that does NOT happen the danger is that a human who is herself electrically grounded (say standing on a wet floor) touches the live pipe: current flows through the human and the human is shocked, burned, or killed.

Heat is generated at points of electrical resistance. In an engineering formula we'd write

P = Power = HEAT measured in Watts = I X V

where I = the amount of current (measured in Amps) through the resistor (in this case the resistor is the pipe and circuit formed by it and its components and connections to earth)
and
Where V = the voltage drop across the resistor

If for example the circuit breaker that was supposed to be on duty protecting the electrical circuit that you described was rated at 15Amps, then 15A of current could flow without tripping the breaker. It's possible that current at or below 15A was flowing through the pipe and the connections you described - too little to trip the breaker but enough to generate enough heat to melt the rubber connector. But because it's possible (and common) that more current than 15A would flow through a pipe that is touched by a live wire and onwards to earth, a breaker in that case should have tripped - hence my warning.

It's possible that there was a weak ground through your piping system and that enough current flowed through the water heater connectors to cause enough heat to melt the gaskets as you described.

We're lucky nobody was fried.

On 2015-09-13 by roger

In a copper home plumbing system, a live 115v positive line contacted a copper water line. The breaker did not break, but the flexible water connecting lines at the water heater seemed to have the rubber connecting gaskets melt, and water began spewing out. Mixed with the water was what looked and smelled like burned rubber. Please explain what happened.

On 2015-06-04 by (mod) -

Bill please see your question, our reply, and a link to helpful information from Fluke Corporation in the article above.

On 2015-06-04 by bill

i am replacing my service panel,in my condo, and the conduit running from the sub panel is being used as the earth ground. how can i test this ground?

...

Continue reading  at GROUND SYSTEM INSPECTION - topic home, or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

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• DOUBLE FAULT, LOSS OF ELECTRICITY
• ELECTRICAL GROUND ERROR-CAUSED LEAKS - leaks in metal water pipes traced to improper grounding
• ELECTRICAL SERVICE ENTRY DAMAGE - service entry wire melts & shorts to ground
• GAS PIPING, FLEXIBLE CSST for a discussion of lightning protection needed for flexible stainless steel tubing used as gas piping
• GROUND SYSTEM INSPECTION - home
• SAFETY for ELECTRICAL INSPECTORS - home

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