New Metal shop

[jjeff]

Well, I meant as the grounding conductor back to the panel? Wouldn't it make more sense instead of running three wires through emt? Isn't that allowed with nec? I'm just curious and want to learn. My pole barn up north was Inspected and passed 8 yrs ago using emt As the grounding conductor. I might change it up and run a third dedicated ground if it's not safe. As I said I'm not a licensed or certified electrician however I have worked with a few that were and a lot more knowledgeable than me.

 

[DaBear3428]

Well, I meant as the grounding conductor back to the panel? Wouldn't it make more sense instead of running three wires through emt? Isn't that allowed with nec? I'm just curious and want to learn. My pole barn up north was Inspected and passed 8 yrs ago using emt As the grounding conductor. I might change it up and run a third dedicated ground if it's not safe. As I said I'm not a licensed or certified electrician however I have worked with a few that were and a lot more knowledgeable than me.

it can be nec compliant but not a good idea, it was done for a long time but we in the industry noted that after the buildings had aged the conduit connections had become lose and or corroded leading to lack of continuity for the grounds. this is also subject to be found by some unsuspecting person that touches the equipment and becomes energized. In a metal shop building that may be a wet environment, saving a few cents for the cost of a copper wire may cost the life of someone. to me not worth the chance.
The NEC 250.118.(4) 2017 edition identifies EMT electrical metallic tubing as an acceptable equipment grounding conductor as long as you are using UL listed fittings and proper methods, so yes it is legal but my professional experience from older professional installed electrical distribution systems points out that there are a lot of issues that can come together as the building ages even when installed by an experienced professional. there is much less room for error with that system that a solid cheap conductor avoids.

in short run a conductor and using proper technique is not fool proof but it is idiot resistant.

I'm not trying to be the TBN electrical hall monitor, just passing on some experience.

 

[EddieWalker]

On a side note, I have a client with a house that used her Natural Gas pipe to ground her electrical panel. When lightning hit a tree in her back yard, the electricity went down the tree, to the Black Iron Pipe in the ground, then into her house and then her panel, where it melted everything in her panel and fried just about everything electrical in her house.

I don't know if she could of avoided this if she had a proper ground rod instead of using the pipe, but this is the only house that I've ever seen lightning do this.

For me, it's pretty easy to run a ground wire inside conduit and pound in one or two ground rods. For my electric fence, I put in 3 ground rods, but that's totally different then grounding a house.

 

[DaBear3428]

On a side note, I have a client with a house that used her Natural Gas pipe to ground her electrical panel. When lightning hit a tree in her back yard, the electricity went down the tree, to the Black Iron Pipe in the ground, then into her house and then her panel, where it melted everything in her panel and fried just about everything electrical in her house.

I don't know if she could of avoided this if she had a proper ground rod instead of using the pipe, but this is the only house that I've ever seen lightning do this.

For me, it's pretty easy to run a ground wire inside conduit and pound in one or two ground rods. For my electric fence, I put in 3 ground rods, but that's totally different then grounding a house.

per the NEC (from 2017 NEC handbook) it should have been the metal pipe AND several other things including a ground rod

i was involved as an expert witness in a case where a Home automation contractor installed a lot of home av equipment and automation equipment along with surge suppressors (think 100 of 1000s of $s) only to have lightning strike the exterior of the home which was stucco clad with the metal lath on the exterior, the lath was grounded to the grounding system but the system was not effectively grounded (older home remodel) so the lightning strike bypassed the surge suppressors (lots of $s worth) and fried the entire home automation system. all that damage just to avoid installing some grounding jumpers and proper ground rods. the home owner canceled the law suit after we pointed out the flaw.

Grounding is viewed as simple but is in fact one of the most complicated parts of my job. one of the purposes of a grounding and bonding system is to direct unwanted electrical currents to a safe destination and to keep the building or personnel from becoming the path of least resistance. funny how the human body and buildings are alike in that they hate stray currents.

 

[EddieWalker]

The client is an elderly widow in her 70's that bought the house because it was cute. It's a 1930's Tudor that is falling apart, but still cute looking. I've been repair issues as they happen, but she can't afford to fix everything. And to be honest, she puts more money into closets for all her clothes then she does for wood rot.

After the lightning strike, I called an Electrician that I trust, and I had him look over the house. He replaced her panel, and did something to protect the house from lighting in the future. I didn't follow up on any of that, she dealt with the Electrician once I introduced them.

 

[woody]

It's coming on and looking good. I do have some electrical experience and that maybe why I enjoy a good electrical discussion because I continue to learn and sometimes it just reminds me of things I have forgotten. I have a ground rod at the building now but I plan on installing another

 

[dieselcrawler]

Nice to see you are getting a new garage/shop. Have to admit, I'm a bit jealous, I need one of my own, as the farm we moved to recently doesn't have a good space for vehicle repair and such, away from the barn animals.

I have a few comments on the electrical aspect, been in the trade for 25+ years. I can't quote NEC chapter and verse, but may look it up if needed. These are simply my thoughts and general practices, not 'hard and fast' rules, all subject to applicable NEC guidelines. And you may be in an area, as I am, where there is no inspection or authority having jurisdiction, and anything goes. Proceed with common sense!

PVC conduit inside... rule of thumb here has been to not do it. PVC when burnt puts off toxic fumes, so I've always avoided using it in homes, basements, structures inhabited by humans. Perhaps, in a garage situation, it may be acceptable, but I dont know for sure. Personally, I would use EMT and/or MC cable inside your garage, but no closer to the floor than 24". In a true mechanic shop, where gas fumes may be present, which settle to the floor, up to 24" can actually be considered a hazardous area, and requires explosion proof conduit and fittings.

Please take the time to run the actual ground wire in the EMT conduit. Required or not, it is your safety net, and you want that in top condition. All it takes is one loose fitting at a rusty box to open the ground continuity. I would also make sure you have GFI protection on all 120v outlets.

Grounding grounding grounding... I would put ground rods in for your new building, even if you're not putin in a full-blown electrical service (breaker panel, etc) and be sure the ground from the power supply and new ground rods/wire are bonded properly. And, always be sure to not tie grounds and neutral wires together anywhere past the power source where the main breaker is (AKA the 'service entrance equipment')

I may be repeating what others a have said, or you already know, but once I get on a train of thought, it all just comes out.

Enjoy your new building... I'm sure it will be nice to have the extra space.

 

[DaBear3428]

Nice to see you are getting a new garage/shop. Have to admit, I'm a bit jealous, I need one of my own, as the farm we moved to recently doesn't have a good space for vehicle repair and such, away from the barn animals.

I have a few comments on the electrical aspect, been in the trade for 25+ years. I can't quote NEC chapter and verse, but may look it up if needed. These are simply my thoughts and general practices, not 'hard and fast' rules, all subject to applicable NEC guidelines. And you may be in an area, as I am, where there is no inspection or authority having jurisdiction, and anything goes. Proceed with common sense!

PVC conduit inside... rule of thumb here has been to not do it. PVC when burnt puts off toxic fumes, so I've always avoided using it in homes, basements, structures inhabited by humans. Perhaps, in a garage situation, it may be acceptable, but I dont know for sure. Personally, I would use EMT and/or MC cable inside your garage, but no closer to the floor than 24". In a true mechanic shop, where gas fumes may be present, which settle to the floor, up to 24" can actually be considered a hazardous area, and requires explosion proof conduit and fittings.

Please take the time to run the actual ground wire in the EMT conduit. Required or not, it is your safety net, and you want that in top condition. All it takes is one loose fitting at a rusty box to open the ground continuity. I would also make sure you have GFI protection on all 120v outlets.

Grounding grounding grounding... I would put ground rods in for your new building, even if you're not putin in a full-blown electrical service (breaker panel, etc) and be sure the ground from the power supply and new ground rods/wire are bonded properly. And, always be sure to not tie grounds and neutral wires together anywhere past the power source where the main breaker is (AKA the 'service entrance equipment')

I may be repeating what others a have said, or you already know, but once I get on a train of thought, it all just comes out.

Enjoy your new building... I'm sure it will be nice to have the extra space.

Good points and I agree with all you have said, the point about GFI outlets is infact code for most areas in a shop as we are discussing as it is more like a home garage. It is highly likely that someone some time is going to decide to plug into one of those outlets and run a cord outside to power something.

 

[DaBear3428]

View attachment 771082
It's coming on and looking good. I do have some electrical experience and that maybe why I enjoy a good electrical discussion because I continue to learn and sometimes it just reminds me of things I have forgotten. I have a ground rod at the building now but I plan on installing another

Nice! Be sure and bond that building frame to the ground system

 

[DaBear3428]

I had a project where the electrical contractor was installing parking lot lighting poles near a overhead 69kV transmission line they were just outside the required safety clearance. I get a call that something was wrong because the electricians were getting shocked while in the lift everytime they touched the pole. Instead of arguing with them I went out to the site and asked for a safety ground strap to be applied between the lift Frame and the ground point on the pole. Magicaly the issue disappeared, the electrical Forman is looking at me with a question on his face so I tell him that it wasn't the light pole that was charged it was his lift picking up inductive currents from the transmission lines.

Point being you never know where or what may become charged and a few dollars worth of copper and some fittings may save your life.