mike93lx
ALLIANCE MEMBER
Hopefully you dont need to bring the wire inside. If you do, cancel and switch to the one I posted
Ground Rod Wire Size and Location in Main?
- Thread starter jaw22w
- Start date
wyliesdiesels
Well-known member
that is URD. cant go inside
4 AWG Mercer URD Direct Burial Cable - Single Aluminum Conductor
Mercer 4 AWG Single Aluminum Conductor 600V URD. Sold by the foot.www.wireandcableyourway.com
wyliesdiesels
Well-known member
wrong wire if it needs to go inside
I was just in the process of apologizing to PCustoms to tell him that I copied the wrong post. I actually ordered the wire you suggested, because it has to come inside. Thanks!
mike93lx
ALLIANCE MEMBER
All good, glad you're moving this forward
No reason to apologize.
I read "direct bury" and grabbed URD, I didn't realize you were bringing it inside. Posting while multitasking....
mike93lx
ALLIANCE MEMBER
TractorJeff
Well-known member
FWIW: Alfred copied the Code and posted it, highlighting certain parts of the statement. I interpret it to say as long as ALL the Wires are in the Trench?
Yeah me too! I think I have everything in line. Just waiting on parts now. The spray foamer is due is less than 2 weeks, so I need to get this done.
You all have been a great help. I wouldn't have made it without you guys!
Here is my interpretation. install the 3 wire system so it is a completed installation, but don't fill in the trench. Add the #4 to the existing 3 wire system. Fill in the trench. Done. All to code.
I'm not too worried. Nobody around here is ever going to catch that anyway. Least of all the inspector.I just re-read this thread to reinforce it in my mind and this jumped out at me. As you said, there is URD coming in to the barn with the 4/0-4/0-2/0. It would not be a bad idea to add a disconnect on the wall of the barn outside of the 200 amp panel in the barn. It would be easy enough to do at this point to keep the URD outside. I think I would have to have a non-URD 4/0-4/0-2/0 to connect between the disco and my panel then.
Is this a possibility?
I apologize for all these questions. I just like to do everything myself. I built my own house, my home shop, and my son's house. I even built the car I drive everyday. But I am just smart enough to know what I don't know. That's why I came here.
Thanks guys!
mike93lx
ALLIANCE MEMBER
It has to be 4-wire and the barn panel will need all neutrals isolated.
4/0-4/0-4/0 Aluminum SER Cable w/ 2/0 Ground
4/0-4/0-4/0 Aluminum SER Cable w/ 2/0 Ground
www.wireandcableyourway.com
Thanks. I just looked and some of those disconnects get kinda pricey. It's only 100 feet clear path to the main to shut it off. I think maybe I'm willing to risk it. I don't think I want to be in the barn if it is burning anyway!It has to be 4-wire and the barn panel will need all neutrals isolated.
4/0-4/0-4/0 Aluminum SER Cable w/ 2/0 Ground
4/0-4/0-4/0 Aluminum SER Cable w/ 2/0 Ground
sparky 1971
Well-known member
You could if you really wanted to. You could go into the bottom of the disconnect then ****** out the back into the back of the panel. The URD could also be dual rated for indoor use so there wouldn'tbe cayse for concern. I know what I wouldn't do. If my shop ever catches on fire I won't be in it because I'll be too busy setting up a roadblock to keep the fire department away.
alfredeneuman
Well-known member
To me "existing" means already installed and passed by an inspector.
mike93lx
ALLIANCE MEMBER
If your shop catches fire, definitely call the FD. To let them know of a huge fire at a church across town.
sparky 1971
Well-known member
See post #5.
wyliesdiesels
Well-known member
except the inspector screwed up and missed a huge issue
sparky 1971
Well-known member
Since it's a volunteer department and I know most of them, I used to say I'd call 911 to announce that the beer is on me for the next two hours, report to the tavern. Now that it's a well known fact that I've quit drinking, some fun hater might figure what I have in mind. I think a flat truck tire that leads to a jack knifed trailer in the middle of what the county claims is a road would work just as well. It would definitely be more cost effective.
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alfredeneuman
Well-known member
And that why I ***umed that it was not inspected.
(Thanks to Sparky1971 for the post #5 info)
My take on that code provision is that it's one to avoid inductive heating (not a problem here) and to reduce the risk that someone makes a mistake and mixes up wires from different circuits, and ends up with an overloaded neutral or something. That's not happening here, so I don't see a real problem.
I am enjoying you guys debating the code in reference to my project. I'm learning. I've learned a lot about service entrance in the last few days on this thread and still learning.
I'm sitting here waiting for parts, just itching to get at it. Couple of days yet for parts, though. I wanted to make sure of the wiring diagram for my 4-wire service. So I took a few minutes to draw my panel. I think I've got it but wanted to make sure. I figure I will get a much better inspection here than from the county.
When I get parts and get the panel wired up, I will post a pic for final inspection.
Quick question. I might as well go ahead and install the 2nd ground rod. Where does the 2nd bare #4 land in the panel. Either ground bar?
Thanks for sticking with me!
I know, my panel is upside down. It made more sense to me for my application, and I checked. As far as I could tell, it is ok by code, as long as the top breaker is less than six feet and the breaker switches are horizontal.
I'm sitting here waiting for parts, just itching to get at it. Couple of days yet for parts, though. I wanted to make sure of the wiring diagram for my 4-wire service. So I took a few minutes to draw my panel. I think I've got it but wanted to make sure. I figure I will get a much better inspection here than from the county.
When I get parts and get the panel wired up, I will post a pic for final inspection.
Quick question. I might as well go ahead and install the 2nd ground rod. Where does the 2nd bare #4 land in the panel. Either ground bar?
Thanks for sticking with me!
I know, my panel is upside down. It made more sense to me for my application, and I checked. As far as I could tell, it is ok by code, as long as the top breaker is less than six feet and the breaker switches are horizontal.
sparky 1971
Well-known member
You're going to run one #4 for both rods. You can take the wire through the clamp on the first rod then on to the second. Or, you can go to the first rod, clamp the wire to it, then add a second clamp to the first rod and go to the second with another chunk of wire. 99% of the time I use option #1. Option #2 is reserved for when I have two pieces of wire and neither one is long enough.I am enjoying you guys debating the code in reference to my project. I'm learning. I've learned a lot about service entrance in the last few days on this thread and still learning.
I'm sitting here waiting for parts, just itching to get at it. Couple of days yet for parts, though. I wanted to make sure of the wiring diagram for my 4-wire service. So I took a few minutes to draw my panel. I think I've got it but wanted to make sure. I figure I will get a much better inspection here than from the county.
When I get parts and get the panel wired up, I will post a pic for final inspection.
Quick question. I might as well go ahead and install the 2nd ground rod. Where does the 2nd bare #4 land in the panel. Either ground bar?
Thanks for sticking with me!
I know, my panel is upside down. It made more sense to me for my application, and I checked. As far as I could tell, it is ok by code, as long as the top breaker is less than six feet and the breaker switches are horizontal.
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Gotchya! Thanks! I am going to assume my panel drawing is correct, then?
sparky 1971
Well-known member
Looks good. Make sure to not use the green screw.
I'm really enjoying reading this thread. I'm new here and I have a question and this seems like a good place to ask it instead of starting a new thread.
Given: Code requires 4 conductors from the main panel to the sub panel in a detached building, and the sub panel to have the bonding screw removed, as well as two ground rods or a UFER ground. I think I got that right.
The old school way of doing it was to just run three wires from the main to the sub, and the detached building had it's own ground, either with rods in the ground or UFER. That's the way we built my shop in AZ in 2003, my dad wired it and he was a Union Electrician in Chicago back in the 50s-60s. He moved to AR in 71 and lost track of code changes as that county had no inspections either and he was formally trained, all be it during the 1950 when electricity was still kinda new. He passed away in 2012, born in 1932. Him and Edison used to drink together down at the tavern! I miss him a lot. Anyway the inspector made us add a ground wire to the ditch and remove the bonding screw, we did that but dad grumbled (cranky old man). However I work for the government and understand following rules regardless of how much sense they make or what I think!
Why was the code changed? What was happening, what was the danger if the detached building with the sub panel has a good ground?
If you are running the ground from the main panel to the sub panel, why is an earth ground (sorry I forgot the correct term, I'll read the FAQ again) necessary? The only answer I know is because code says so. Do any of you guys know the scientific answer?
Lots of code changes make simple sense, like grounding metal appliances so you don't get electrocuted when a wire in grandpa's old aluminum drill breaks and touches the housing. GFCI makes sense, no brass no ammo kinda thing. But this one is beyond me unless it has to do with fault detection of the sub panel itself, so a fault in the sub panel, not one of the circuits it provides, will trip the breaker in the main panel.
BTW I'm having a shop built this winter and I'll be wiring it. Building permits in my county cost $20 and the inspection makes sure setback requirements are met. But I want to do all this to code even if the county don't care.
Thanks
Rob
Given: Code requires 4 conductors from the main panel to the sub panel in a detached building, and the sub panel to have the bonding screw removed, as well as two ground rods or a UFER ground. I think I got that right.
The old school way of doing it was to just run three wires from the main to the sub, and the detached building had it's own ground, either with rods in the ground or UFER. That's the way we built my shop in AZ in 2003, my dad wired it and he was a Union Electrician in Chicago back in the 50s-60s. He moved to AR in 71 and lost track of code changes as that county had no inspections either and he was formally trained, all be it during the 1950 when electricity was still kinda new. He passed away in 2012, born in 1932. Him and Edison used to drink together down at the tavern!
I miss him a lot. Anyway the inspector made us add a ground wire to the ditch and remove the bonding screw, we did that but dad grumbled (cranky old man). However I work for the government and understand following rules regardless of how much sense they make or what I think! Why was the code changed? What was happening, what was the danger if the detached building with the sub panel has a good ground?
If you are running the ground from the main panel to the sub panel, why is an earth ground (sorry I forgot the correct term, I'll read the FAQ again) necessary? The only answer I know is because code says so. Do any of you guys know the scientific answer?
Lots of code changes make simple sense, like grounding metal appliances so you don't get electrocuted when a wire in grandpa's old aluminum drill breaks and touches the housing. GFCI makes sense, no brass no ammo kinda thing. But this one is beyond me unless it has to do with fault detection of the sub panel itself, so a fault in the sub panel, not one of the circuits it provides, will trip the breaker in the main panel.
BTW I'm having a shop built this winter and I'll be wiring it. Building permits in my county cost $20 and the inspection makes sure setback requirements are met. But I want to do all this to code even if the county don't care.
Thanks
Rob
wyliesdiesels
Well-known member
I explain the answer to your question on the electrical FAQs sticky but the short of it is, the grounding electrodes are a different animal than the EGC between the panelsI'm really enjoying reading this thread. I'm new here and I have a question and this seems like a good place to ask it instead of starting a new thread.
Given: Code requires 4 conductors from the main panel to the sub panel in a detached building, and the sub panel to have the bonding screw removed, as well as two ground rods or a UFER ground. I think I got that right.
The old school way of doing it was to just run three wires from the main to the sub, and the detached building had it's own ground, either with rods in the ground or UFER. That's the way we built my shop in AZ in 2003, my dad wired it and he was a Union Electrician in Chicago back in the 50s-60s. He moved to AR in 71 and lost track of code changes as that county had no inspections either and he was formally trained, all be it during the 1950 when electricity was still kinda new. He passed away in 2012, born in 1932. Him and Edison used to drink together down at the tavern!
Why was the code changed? What was happening, what was the danger if the detached building with the sub panel has a good ground?
If you are running the ground from the main panel to the sub panel, why is an earth ground (sorry I forgot the correct term, I'll read the FAQ again) necessary? The only answer I know is because code says so. Do any of you guys know the scientific answer?
Lots of code changes make simple sense, like grounding metal appliances so you don't get electrocuted when a wire in grandpa's old aluminum drill breaks and touches the housing. GFCI makes sense, no brass no ammo kinda thing. But this one is beyond me unless it has to do with fault detection of the sub panel itself, so a fault in the sub panel, not one of the circuits it provides, will trip the breaker in the main panel.
BTW I'm having a shop built this winter and I'll be wiring it. Building permits in my county cost $20 and the inspection makes sure setback requirements are met. But I want to do all this to code even if the county don't care.
Thanks
Rob
The grounding electrodes are for shunting lightning, limiting potential to earth etc but cant aide in clearing fault current. Thats the job of the EGC. Just like in your example about appliances
Thanks, I read your post in the FAQ a few times and still don't understand why it took till 2008 to make the change. If I have a garage built in the 90s with a 3 wire feed from my main panel how is it more dangerous than one built today. i also red this.
https://www.creia.org/assets/docs/pdfs/sub-panel-grounding.pdf
I'd do more reading, I have a full pot of coffee!
https://www.creia.org/assets/docs/pdfs/sub-panel-grounding.pdf
I'd do more reading, I have a full pot of coffee!
alfredeneuman
Well-known member
(E) Supplemental Electrode Bonding Connection Size. Wherethe supplemental electrode is a rod, pipe, or plate electrode, that portion of the bonding jumper that is the sole connection to the supplemental grounding electrode shall not be required to be larger than 6 AWG copper wire or 4 AWG aluminum wire.
The rods will be buried so aluminum would be no good.
sparky 1971
Well-known member
I know a #6 would be ok but I believe he already has #4. See post #62. It also looks to me like a #4 was installed previously, see the photo at the beginning.
And, here, certain places prefer us to use #4 because of the dreaded weed eaters. There is no written amendment, but I do it anyway just because it's easier to carry one spool of #4 vs a #4 and #6.
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wyliesdiesels
Well-known member
Why did it take the CMPs that long to change it? I cant answer that
As to being more dangerous, it does have the potential since the neutral is bonded. If that neutral developed a bad connection somewhere, you could have stray neutral currents running on unintended pathways… it sets up a potential for shock…
Metal-Marc
Well-known member
FYI, always best to start your own thread instead.
wyliesdiesels
Well-known member
yup too many details that end up hijacking someone elses thread
I just wanted to take a minute to say thanks to all the people who contributed their time to my project, especially, sparky1971, Wyliesdiesels, and mike931x. Not to slight anyone. You were all a great help.
Sunday, I finished the last hand digging and got the barn service entrance cable connected to the main panel. Switched the 200 amp breaker on at the main then the sub in the barn. Hit the breaker for the lights and flipped the switch. Lights came on. No smoke anywhere and no tripped breakers. I have tested every circuit. Everything tests good, even the GFCI circuits. I guess that ain't too bad for an old Ironhead.
I am really glad I came here for advice. I got an up-to-date, safer system, in spite of my worthless county inspectors that were only going to look for one ground rod and a couple of GFCI receptacles. I think my total extra cost to do it right was $78 and very little labor. Damn good value!
I am ready for the spray foamers on Friday.
Thanks All!
Sunday, I finished the last hand digging and got the barn service entrance cable connected to the main panel. Switched the 200 amp breaker on at the main then the sub in the barn. Hit the breaker for the lights and flipped the switch. Lights came on. No smoke anywhere and no tripped breakers. I have tested every circuit. Everything tests good, even the GFCI circuits. I guess that ain't too bad for an old Ironhead.
I am really glad I came here for advice. I got an up-to-date, safer system, in spite of my worthless county inspectors that were only going to look for one ground rod and a couple of GFCI receptacles. I think my total extra cost to do it right was $78 and very little labor. Damn good value!
I am ready for the spray foamers on Friday.
Thanks All!