2020 NEC Changes series: 250.68(C) Grounding electrode conductor connections
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- Опубликовано: 1 дек 2021
- The NEC no longer allows rebar to be used as an interconnection between grounding electrodes. This videos explains the ramifications of the change and why it happened.
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I appreciate your directness while saying plumbers are evil.
They really are.
LOL
All of the worst examples of the trades taking the easy way out come from plumbers. Have a joist in the way of a plumber? Say goodbye to it. Didn't really need that joist anyways.
Great video Ryan! Always informative and I love that you keep it real!
"spliced with water"
so like a toaster in a bathtub?
XD, made my day.
Thank you Sir I followed you Your Lecture is very easy for understand to NEC
Good lecture. Thank you!
Great explanation. Thank you.
Hey Ryan, We never intended for the concrete encased electrode to be used as a bonding jumper to interconnect other electrodes. Although it was never tested as you mentioned, and that is one of the reasons we clarified the language in the 2020 edition. We did allow it for the metal frame of a building because 1) it is NOT likely to have the continuity of the metal frame interrupted the way metal water piping is likely to be interrupted. and 2) it is suitable for systems that have ungrounded service conductor that exceed 1100 kcmil CU or 250kcmil AL, in other words, no matter how small or how large your service is, the metal frame is akin to a properly sized wire type bonding jumper. With metal water piping it is the same issue, (as long as it is connected within the first 5' as it enters the building) the metal water piping will work again for the smallest service or the largest service. Rebar (concrete encased electrodes are a very different matter. For example, if you had a 3000A service that includes metal frame and a concrete encased electrode, the 4 AWG connection to the electrode is not the same as a 3/0 connection needed for the metal frame and using the 4 AWG to connect metal frame would not meet the requirements of the NEC.
I agree.
I've always thought rebar to be a bad choice. Unless it's tested, there's no telling if it's actually contiguous, or driven into the ground anywhere. All it takes is one concrete saw and your ground is no longer a ground, and you'd never even know it. Water pipes would also have to be tested, even if you can visually see it going into the ground -- how deep is it, and how far does it go before becoming plastic?
While my house (80's) has a copper inlet -- 2' down, ~20ft to the meter -- it's grounded from a dedicated ground rod a few feet from the service connection. ("first disconnecting means") My parent's house (60's) used to be grounded from a cast iron pipe. A decade+ ago that was replaced with a proper copper rod when backup power was installed.
The problem isn't his explanation of the code but inexperienced electricians . Ive seen a lot grounding practices from Jack Leg electricians who just don't know.
What is code if a #4 ground wire is connected to the rebar within the footings of the slab that is encased, thus the bare wire is the only thing visible within the wall? Is this NEC 2020 code compliant?
@@KrazyKajun602I wish someone would answer this I'd like to know to.
Hey Ryan, on an existing pole barn for a 200 amp service with no plumbing or rebar stubbed up what would be the option? Also building has R panel so that would be bonded.
So if I may ask, can we then use Ufer in commercial or residential as grounding method?
Hi..Ryan,can you explain me what is the size wire for foundation grounding for building???/.abel casanova
Thank you Ryan!!
Kansas City, Kansas / Wyandotte County requires copper waterpipe to the water meter still.
Is a duplex with one continuous foundation allowed to have two SEPARATE Ufer grounding systems with 4 ga. copper wire connected at three separate points with approved concrete contact connectors 20' along the the concrete encased 20' long rebar for two separate 200 amp services, i.e. each service panel is connected separately to the rebar in the footings? I would use the flexible conduit to encase the 4ga. copper wire from the footing up through the slab below where the panel would be in the basement.
Very good that makes very good sense.👍
Mis speaks, and then takes a big swig of his beer...haha, thank you for being a regular dude!
Plumbers? Evil? That kind of speech is gonna get my electrodes purposely cut.
Only if an electrician is available to help the plumber understand the big words. LOL On our jobs I point out to the plumbers that they can be replaced by a plastic outhouse and a brother-in-law that needs a job really bad.
When's the last time I saw a copper water pipe underground? Every day lol
I guess it depends on where you are! 🤷
Here in the Philadelphia area they have used nothing but copper to feed houses & small businesses. They are slowly changing over to Led tubing after the water meter. Wired a large house a few years ago where the water meter was at least 150' from street. They installed an underground water meter by street and ran 1" type K copper tuning to supply the house.
The trend is to switch to PEX even in feed from the main in the street is trending to plastic. Here in Chicago all water pip is underground like 3 feet or more probably 4 feet so as to not freeze in winter but in the Southwest I see it above ground all the time. Personally , using water lines inside a building for ground is bad because plumbers routinely take that apart and if the screws on the bonding wire clamps are rusty then they are not going back on.
Lol when I heard spliced with water my brain crashed but then was rebooted when you questioned yourself 🤣
Great video . Happy knife life
As I heard you say “splice with water” I knew I’d already seen this video! 😂😂😂
Hey Ryan, I'm enjoying your videos, but i have a confession to make. Around 15 years ago or so you inspected the electrical install on a new build church, i was using the white wire iin a 12/2 mc cable as my switch legs in every room, you told me to mark them all black, i promised i would and you signed off on 4 way. But i never did LOL!
LOL I can't believe the building didn't burn down without that tape!!! 😅
Ryan is a good guy. You are a dishonest person that you did not keep your word wouldn't want you to ever work on my properties
Hi Ryan, 250.68 (C)(1) allows connection to the extended concrete encased rebar type. If all requires are met, are we allowed to run a#2 aluminum on a 400 amp service being #2 al. Is larger than #4 bare copper?
@@roudibien-aime2198 Yes, 2 AWG aluminum is allowed.
You savage
That’s awesome you kept that spliced with with water 💦. Bravo Ryan 🤣
Just a detail, but I believe that the green wire we see connected to the rebar is a violation. IIRC the NEC specifically excludes the GEC from the list of where green is allowed.
Comments.?
Ryan, I am having a monolithic foundation poured and plan to use a 1/2 20 ft rebar in the footing as the CEE. Can I just have this rebar extended up through the slab and attach that to a #4 using a clamp to bond the service panel ?
Yes
Washington State, Mount Vernon, 2020 NEC: I just got off the phone with a local inspector, and he said that two rebar stub outs at least 20 feet apart (tied via tie wire using std construction practice) into the rebar footings is sufficient provided the rebar length is at least 20 feet. He also said that a #4 copper wire (20 ft bare tied to the rebar structure with 6-7 feet of protected wire) above the concrete) can be used instead of the rebar stub out. So, either system is ok: two rebar stubs at least 20 foot apart or #4 copper wire.
I can see how earth can provide an electrical return, as in a ground. But looking at a rebar imbedded in concrete, something in my head says that no electrons, nor electrical potential, is ever going to travel through that hard concrete thick concrete. It might as well be rebar in a wall of glass. What's the physics that I'm missing?
Is there also a consideration that the rebar of a large structure is not electrically continuous? The rebar won't be a single piece in your IKEA example, but multiple (likely rusty) pieces temporarily mechanically tied with maybe 16 ga. steel wire until it is locked in place with the concrete. Any bonding, even if it had been done, is certainly no longer accessible once the concrete hardens, and I doubt the concrete has a UL label as a bonding conductor.
No, the rebar is still permitted to be multiple pieces tied together with the wire when creating the electrode itself, see 250.52(A)(3). Also, nothing is ever required to be listed by UL, and a conductor doesn't need to be listed at all.
Just putting these questions out there for opinions. This is in regards to a service entrance. If you have both a ufer connection point and a 20+' copper water main available, which would you choose as your grounding electrode? If you choose the ufer, you would still need to bond the water piping. If you choose the water pipe, would you abandon that ufer connection point, or use that as a supplemental grounding electrode? Many local utilities want a driven rod at the meter fitting regardless of what the AHJ requires, so that would qualify as your required supplemental electrode.
You have to use all that are present, and if one of those is a water pipe it must not be the only electrode. So use the Ufer and water pipe and then you're done.
Hi Ryan have you ever seen a water meter that is underneath the ground outside the house? It looks like a small version of a manhole cover. I am used to water meters (like the one in your video) where I would Bond one before the water meter and one after the water meter.
Any ideas? The house was built in 1980
My water heater is underground near the sidewalk.
@@RyanJacksonElectrical water heater??
I was asking about your water main
@@theseattlegreen1871 meter, sorry. It is underground.
@@RyanJacksonElectrical
Okay no problem so how do you bond that?
@@theseattlegreen1871 you don't. It's thirty feet away from the house, so it's not part of the grounding electrode.
Love that comment about plumbers.
Somewhere I saw a table that showed the multiplication factor for multiple ground rods in parallel if one ground rod isn’t less than 25 ohms. It was somewhere in the 250 part of the 2020 NEC I think. Anybody know where it can be found?
250.56
@@im2yys4u81 thanks
What is code if a #4 ground wire is connected to the rebar within the footings of the slab that is encased, thus the bare wire is the only thing visible within the wall? Is this NEC 2020 code compliant?
Yes, either it has to be secured to the rebar or 20ft of the proper grounding conductor size needs to be buried in the concrete (you do the 20ft option when there's not much steel in say a slab to tie into). It just makes it harder to verify that it was done right. Though to be fair I have seen electricians forget to have the rebar stubbed up in the right spot and they'll cheat and drill a hole epoxy a tub of rebar into it and tie onto that. That guy got fired from the company pretty fast.
Why voltage drop down
Defining an electrode as the underground portion is deceiving in that current may be flowing from the connection point on. Many plumbers have been killed opening water mains, and I believe the 5 foot rule is for that reason.
No, the five foot rule is to ensure the premises wiring system will still be connected to the grounding electrode if a plumber replaces an aboveground portion with nonmetallic piping. There will always be current on any grounding electrode because they are in parallel with the utility's grounded conductor.
If I had to guess at their reasoning; the skin effect is the conduction point of the material and the gauge of the material is its heat retention and dispersion factor, a corroded material will see increased resistance reducing or eliminating its ability to conduct a short over the desired distance causing a "blockage" so to speak causing the current to back up at the weakest point of the connection and a failure of connection would be the result.
The skin depth of a 60hz circuit is 8.5mm, so as long as it's at least 17mm thick, corrosion won't have a significant difference in conductivity due to the skin effect.
@@jameskarrie298 false. Oxidized metals have a higher resistance than the base metal. Also; the skin effect is not millimeters deep it is microns deep.
@@jameskarrie298 this is why aluminum is rarely used and never used in buildings for electrical wiring. Many a fire have been caused by lightly oxidized aluminum wire.
@@DawsonTyson If it was microns deep for 60hz, all home wiring would have to be coated stranded wire. I'm not saying iron oxide doesn't have a higher resistance than steel. The higher resistance is corrosion at the connection points.
Now that I did the math, skin depth would be ~109micron for steel (8.5mm is for copper, aluminum is about 5mm).
Another point is that all wiring is surrounded by insulators (plastic or even air), what is a metal oxide layer going to change? It's all about the connection points getting corroded not the skin effect. If the skin effect mattered for having an insulating layer on the conductor, conductors wouldn't work.
@@jameskarrie298 no it wouldn't. We use solid core wire to safely carry high current. Stranded wire bundles offer a lower resistance but are prone to heating up quicker and at lower currents. This is why your vacuum cleaner power cable is warm after 10 minutes or more of use. The reason this works is the beauty of alternating current. If we were still using Thomas Edison's direct current Stranded wire would be the standard so that the power could go further. With A/C we can send more power with the same surface area 100 times the distance. The skin effect will also go deeper into the material at higher power but this sinking into the material is also fueled by heat. Keep it cool and will stay at the surface.
I just had a local building inspector tell me my ground wire to the ground rods ( we are required to use 2, 8 foot rods 6 feet apart) was supposed to be solid wire. I've looked up where it says that in the code and it doesn't, at least not where I can find it. For some reason #4 solid is in short supply, I couldn't find any within 15 miles and was in a crunch. I had 30 ft of #2 braided and used it, quite a bit overkill. He did pass it but not before raising my blood pressure.
It's not required. The Code specifically allows multiple GECs or bonding jumpers. See 250.64(F) and note that a wire between two electrodes is NOT a GEC, but rather a bonding jumper. That means the splicing requirementvof 250.64(C) does NOT apply.
as I recall, the rods should be at least 6 ft apart. Most guys go 8 ft because it's an easy eyeball with no questions. The grounding wire is a solid piece" meaning no splices from the farthest rod to the ground bar in the panel. You can use solid or stranded wire.
Some electricians and inspectors still dont realize the size of the grounding electrode wire is determined by the size of the largest UN-grounded conductor in the service entrance feeders .Its in the code book. . And some inspector's want a solid bare wire not insulated.
Evidently some electricians and inspectors don't read the code. As for the bare solid wire, i guess they have only seen a number six solid going to a ground rod.
@@nooneyouknowhere6148 to be far the book 📖 is thick so remembering all a one time for a pop quiz is hard, i end up reading it more than once for new questions i have or refreshing my memory about a part im working on
And our inspectors now want grounding wires to be shielded in any exposed areas between panel and ground clamp and to second ground clamp
Residentially interestingly is capped (localy anyway) at AWG6 despite it being below the normal feeder to ground ratio at 200A systems
I have to explain this to a lot of electricians who's not aware of the code changes and plumbers cutting out old metal pipes and replacing it with pvc.
EE here. The idea that a continuous rod which is half burred and half not being half grounding electrode and half not is ridiculous if you ask me. The first problem with it is that it almost implies the bonding should be done under ground which would then make inspection impossible. The second part is that its just physically incorrect & under this reasoning you could never bond to the grounding electrode because the second your wire enters dirt the portion of it in the dirt is then a grounding electrode lmao. Of course you want your bond to the grounding electrode to be such that it would never be reasonably open from the grounding electrode, but lets not get carried away here trying to pretend one piece of metal is two just b/c its half buried and half not.
If half of it isn't buried, it increases the resistance to ground. When we are talking about copper, who cares; but if we are talking about steel maybe???? Ideally it should be connected in the ground technically I guess? It's probably mostly due to the argument that the further away it is, the higher chance of someone deciding to cut it, disconnecting the connection to ground 100 years from now.
Super. 💙 T.E.N.
Broooo 3:05 is the most underrated and most ingenious explanation to give customers ~~ PLUMBERS ARE EVIL, EVIL I SAY. But it makes sense logically, most of them come to work drunk lmao
Why can't "ground" be a grounding conductor? -- I know, that's just crazy talk. ---
Seems to me instead of just going on what someone said 70 years ago we should take another, more in depth, look. It could save contractors a LOT of money!
They would just bill it to the customer... It's really making them money if they go by % markup.
Time 5:46 is amazing 😅
🥃🍺🤔👍🏻
5:45 😅
Spliced with water 🌊😅
U just needed a sip of water sir 😅
Well why don’t we just test it then
Go ahead.
Spliced with water.... Have another hahahah
OK.....
A piece of rebar in the concrete is 'never' grounding .... concrete insulates and rebar should never extend into the dirt as it introduces corosion into the rebar framework .... and 'corosion proofing' does not reall work long term and if it is likely interferes with contictivity to earth....
It can be used as a 'grounding plane' for the floor freequently needed gor 'differential' in large / multy floor buildings .... absolutely never considered actual ground
.
Intermaterial bonding creates risk of electrolysis and failed connections , therefore should never be relied on
Stand on a piece of concrete and touch an ungrounded conductor originating from a solidly-grounded system and tell me how well concrete insulates. As far as "actual ground," the NEC defines ground as "The earth." Obviously concrete is not "actual ground." But I never said it was and neither does the NEC.
Here is to water 🍺
Plumbers Evil , don’t think you should have said that . There are a lot of good plumbers out there !
It's a joke...
lighten up Francis
Never trust plumbers 🤣🤣🤣
Plumbers are evil people 😜