Bonding neutral and ground at main panel using a 4- wire connection (hot-hot-neutral-ground), DO NOT bond neutral to ground in the range or dryer. Addtionally, is a #6 CU or #4 AL largest I ever need to the ground rod even if there is no building steel or cold water pipe available or do I have Dec 22, 2023 · Utility (First Energy) relevant information - "3. Feb 23, 2019 · Electrical - AC & DC - Bonding ground to neutral in main panel - I noticed that the ground and neutral bus bars are not bonded in my service panelsee attached pic. For this reason you cannot ground the neutral within both the transformer and at the main bonding jumper in main panel/ first point of disconnect. -Neutral and ground bonded with an unbalanced load If the load becomes unbalanced and ground and neutral are bonded, the current will flow through anything bonded to the sub-panel (enclosure, ground wire, piping, etc. Now the grounded and grounding wires need to be on different bars (neutral bar insulated, grounding bar bonded to cabinet). You loose the neutral and then the smaller ground carries the neutral current and can overheat cause a fire etc. First, we set up a test panel with amp probes to measure the current flow on each wire. Assuming that the ground rod is properly installed with excellent earth bonding, the rod should carry away the externally generated surges like lightning into the earth – protecting the house and building. Your breaker panel in the RV has isolated neutral and ground. Neutral lug is bonded to ground bar in 200 A combination panel. Why Do Neutral and Ground Conductors Need to Be Separated in a Subpanel? According to NEC Article 250, neutral and ground wires must remain separate in subpanels. Jan 10, 2025 · The Importance of Bonding at Service Panels Essentially, we keep neutral and ground bonded at the main service panel due to safety reasons. Obvious shock hazard! Remember, electricity will take any path back to the source. May 12, 2021 · 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 will be in it. I understand ground and neutral are only bonded in the main panel and seperated in any subsequent panels after the main panel and I feel like i have a good grasp on why that is. We understand that neutral and ground wires must be connected only at the main service panel. Because of the required bond in the main panel, a great many electricians conclude that there is no difference between neutral and ground in the main panel since the N-G bond is right there. This involves intentionally connecting the neutral and ground conductors at the service panel. 24 (B) Main Bonding Jumper: • Bonding Screws vs Bonding Straps (NEC Also see: What's the Difference Between an EGC and a GEC?: • What's Here's a short version of the video I did a while back on why we bond neutral and ground together at the service panel of a premises wiring system. Dec 5, 2024 · According to the National Electrical Code (NEC) Article 250, bonding within an electrical panel involves connecting the neutral (grounded conductor) to the equipment grounding conductor and the panel enclosure. Apr 3, 2025 · Bonding jumper: Connects the neutral and ground bars in the main service panel grounding setup (not used in subpanels). Dec 26, 2019 · A risk I see, especially with the 2020 NEC wanting an outside disconnect, is the main panel could one day become a subpanel. My inquiry is this, 1. 24 (A) (1)). You need to seperate the neutrals and grounds in what is now your subpanel. To bond the two bus bars together, this panel will need a bonding strap, or to have the equipment grounding conductors (bare copper) moved to the main grounding bus bar. Jun 17, 2018 · When the ground wires are connected (bonded) to the neutral at the main service panel, the current flows readily through the neutral from there to the transformer. Description: Did you know that bonding the neutral and ground in the main electrical panel is one of the most important safety measures in your home’s electrical system? In this video, we Nov 7, 2022 · At the service equipment, the service grounded conductor connects to the grounding electrode via the grounding electrode conductor. Grounding and Neutral: The Rules One critical distinction between main panels and subpanels is the treatment of grounding and neutral wires: Main Panels: Neutral and ground wires are bonded (connected) in the main panel, ensuring the panel itself is grounded. My understanding is that you only bond neutral to ground at the main disconnect, but I don't know how that applies when there are two disconnects. Many people refer to it as the “main panel Jun 21, 2011 · For example, it changed “bonding and grounding conductors” to “bonding and grounding electrode conductors. Always follow NEC (National Electrical Code) or local codes and consult a licensed electrician if unsure. . Without the grounding wire, that misdirected electricity could shock you. The power company is requiring us to bond the neutral and the ground in the meter base attached to the house. Aug 21, 2024 · Understanding the Basics The neutral conductor serves as the return path for current in an electrical system, while the ground conductor provides a safe path for fault currents. Next, what’s the deal with connecting grounds and neutrals together? In my words, if grounds and neutrals are connected together at a subpanel Dec 29, 2023 · From the service to the main disconnect the neutral plays a dual role and is all that is needed. Jul 16, 2019 · When should the ground and neutral wires be separated at a subpanel? It depends. Feb 2, 2025 · I'm trying to help a friend install a 120/ 240 Subpanel of 1 120/240 main Panel Most of my experience is with my employer, which has strict rules. Learn how to create an electrical panel grounding diagram, ensuring safe and correct grounding connections for your electrical system. Nov 13, 2017 · I have a question about if you bond in the transformer, then why would you also bond in the panel? I was always told and understood that you bond once at the transformer where the service starts and nowhere else. So with that in mind your inside panel is now a subpanel and must be fed with a seperate neutral and ground. Here are the basics on panels and grounding. The current should be balanced in a properly wired panel, with the majority flowing through the hot and neutral wires. Simple definition, right? What’s not always simple is correctly applying the NEC requirements, some of which changed with the 2011 revision. If neutral and ground are bonded at the appliance, the entire neutral return is now flowing through the ground wire, possibly all the way back through conduit, green wires, and the entire bonding system of the house. May 6, 2014 · On a 30 KVA transformer. It is a decision within which you, the electrician, literally have the lives of everyone that will ever go into that facility in your hands. The shop has it’s own meter and electrical bill etc. This could be at the service drop, the meter, or the service disconnect (250. Dec 1, 2023 · The meter base has a 6 awg that connects the grounding bus bar to the neutral/ground lug in the meter base. May 29, 2025 · Drive a ground rod into the earth near the panel. See full list on circuitsgallery. Feb 14, 2025 · Service without disconnect, feeds to interior panel with first point of disconnect (Now making the interior panel the main panel?). During normal operation, the grounding wires can energize equipment enclosures and casings with neutral current (yes, the neutral carries current; the reason the conductors are May 6, 2025 · Even worse is the case of a broken neutral somewhere upstream. Feb 6, 2020 · It appears that there are also multiple neutrals under a single screw, which is a deficiency because it complicates isolating circuits. My question is, why does scenario 2 not pose the same dangers as scenario 1 would if the interior panel also had grounds and neutrals bonded in scenario 1? Jan 19, 2022 · The NEC, in several places, mandates that the neutral (grounded conductor), the equipment ground (grounding conductor), and any main or system bonding jumpers must be bonded at this point, in grounded AC systems. Nov 30, 2023 · Bonding the neutral and ground wires at the panel is necessary for safety and compliance with the National Electrical Code. This connection, known as the main bonding jumper, is typically made at the main service panel or the first means of disconnect, which would be outside next to the meter. The integrity of the entire system depends on correct installation, tight connections, and code compliance. Should one of the bonding screws be removed? Edit: not shown, but there's another 200A breaker in the main panel. Do I bond the ground and neutral in the main disconnect or panel also. The meter base also has a 5/8 grounding rod that has a seperate 6-awg bonding from it. By bonding the equipment grounding conductors to the system neutral, there is now a path back to the transformer from where the power came. Jan 11, 2012 · If your installing the service rated transfer switch between the meter and the inside panel then the transfer switch has just become the main service disconnecting means. Apr 26, 2018 · I have seen that in the main panel that my neutral should be bonded to the ground in the main panel and not in the sub panel. Feb 18, 2013 · 1) Install system grounding conductor in meter base by running insulated copper wire from meter base to ground rods (or ground plate) and bond to system neutral on service side of meter base. The sub panel is just wrong. NEC 2008 states that the neutral and ground wires should be “bonded” together at the main panel (only) to the grounding rod. Ultimately this question is, why bond neutral and ground in the main panel, but not the subpanel (besides NEC said so)? Why is the neutral from the main panel to the subpanel inherently different from the service neutral to the main? Apr 15, 2016 · Neutral and ground should only be bonded at the service equipment. Dec 7, 2024 · This setup simplifies wiring and enhances system organization. You should be able to buy a second bar for the sub-panel if it really is meant to be used as a sub-panel. The ground busbar terminal in the service equipment (main panel) should be securely connected to the grounding rod using a properly sized equipment grounding conductor, as specified in NEC Table 250. So they are bonded outside in the disconnect and also bonded inside at the main panel; usually less than 6 feet apart. 28] is required to connect the neutral conductor to the equipment grounding conductor within the service disconnect [250. Why Neutrals & Grounds are Connected in a Main Panel Benjamin Sahlstrom 458K subscribers 41K Aug 26, 2023 · A critical part of this system is understanding the connection between the neutral and ground wires. 24 (C)]. Grounds and neutrals now become bonded at the interior panel. In a three-phase system, the neutral is often connected to the earth at the main service panel, which is the only point where neutral should be bonded to ground. 5 days ago · Internal Wiring and Bonding Requirements The feeder supplying the sub panel must include four conductors: two hot conductors, one neutral (grounded conductor), and one equipment grounding conductor (EGC). 122. The IEC does a much better job making this clear while the NEC is terrible at it. The sub panel ground should not have a ground rod tied to it. As graphically illustrated in Sir Mike Holt books, the main panel which contains the Main disconnecting device is separated from the branch circuit protective devices (which is technically, Sub-Panel). The neutral and ground MUST NOT be bonded at a sub-panel. A service neutral conductor must be run from the electric utility power supply with the ungrounded conductors and terminate to the service disconnect neutral terminal [250. Oct 22, 2024 · As long as the neutral and ground are bonded with the bonding screw at the first disconnect, separating them is optional, though required in subpanels. So in this case the service neutral connects the panel to the grounding electrode system. At the main service panel, the neutral and grounding wires connect together and to a grounding electrode, such as a metal ground rod, which is there to handle unusual pulses of energy, such as a lightning strike. Whether you’re a homeowner, an electrician, or an engineer, understanding the principles of grounding and bonding can help ensure that electrical systems are not only efficient but also safe from potential hazards like electrical shocks and fires. First, what’s a subpanel? In my words, a subpanel is an electrical panel wired downstream from the Service Equipment, which is more commonly known as the main panel. 24 (B)]. Consider the following scenario: a wall inside a building with two electrical panels. The neutral bar will need to be Electrical Grounding & Bonding: Top Mistakes to Avoid for a Successful Installation: Don't make common mistakes that can lead to a dangerous electrical system. Using a 4-wire connection and still bonding neutral and ground would be a disaster for the reasons you cite. The difference between a service panel and a sub panel is also muddy in many minds. Hope this helps! I am installing a 100A main panel back-to-back with the meter base and need help confirming where to bond ground and neutral. Jul 26, 2017 · A detached structure with a panel fed by a feeder always requires a grounding electrode system, could be two ground rods. Because both panels are considered main panels, neutral and ground need to be bonded together. Run a copper GEC from the ground rod to the panel. But when the neutral and ground wires are connected further back at a subpanel, they both carry current back to the main panel. This bonds the neutral bus to the metal enclosure. The neutral-to-ground bond was in fact invented to save money so that a grounding wire did not have to be run from the transformer to the first panel. That could be ugly depending on the lengths of wire you have in the panel and if you only have a neutral bar on one side whereas before you had Feb 24, 2021 · Case 2. Connect the GEC securely to the ground bus bar. The neutral-to-ground bond is a topic Mar 24, 2019 · The topic of grounding and bonding is a never ending area of confusion. This setup ensures that any grounded conductor doesn't carry current under normal conditions but can carry fault current back to the main panel where the breaker can trip. Learn why bonding these ensures proper breaker function and prevents electrical hazards. By doing this, should the main breaker Neutral-to-ground bonding is crucial for safety in main panels. If you bond at transformer and panel then you are paralleling the neutral and ground. From the meter base run 2 black and one white to combination panel with main disconnect. Apr 9, 2025 · The neutral and the ground would catty current so if someone disconnected the ground at the main panel there is a possibility of someone getting hurt. 🤘⚡️EU Lea Jul 7, 2023 · To avoid routing the ground to a separate bus bar to keep a workman-like appearance, can the neutral and ground be bonded inside the main service panel and then sent to the plug-on neutral bus bar An important question was raised by one of our viewers. I used to think this was clear cut, but recent discussion has clouded the issue. But this is ONLY allowed in the main panel— never a subpanel, or anywhere else in the home. Feb 22, 2022 · Good day engineers, I've read that, bonding of neutral bus and ground bus shall only be done at the MAIN PANEL. com Mar 17, 2025 · The neutral and ground wires should only be bonded (connected) in the main panel, where it is the designated bonding point. Aug 10, 2018 · Parallel Paths One of the most common defects I find related to remote distribution panels (sub-panels) is ground wires and neutral wires bonded together. Second, the main electrical panel must be grounded to a grounding electrode such as a ground rod or rods A main bonding jumper [250. Ensure proper bonding for a safe system. Oct 10, 2024 · Immediately adjacent on the inside of the home there is an indoor panel with a main disconnect and all the circuit breakers. Bonding (connecting) the neutral and ground should only occur in the main panel or at the first service disconnect. In the event of a ground fault, the neutral wires can conduct fault current. Mar 27, 2009 · Bonding of the neutral and ground bus bar (if so equipped) occurs at the main panel only. Jun 25, 2024 · A missing bond between ground and neutral at the main panel could be the culprit. The generator cannot be grounded to a rod because this would tie the neutral to ground in a second location through the bond. They should only be bonded at the main service panel. Jun 17, 2018 · So neutrals and grounds on the same bonded bus bar at a subpanel, or neutral and ground bus bars with a bonding connection between them at a subpanel, is definitely not “grandfathered in” as alright. Jan 18, 2017 · 2 I know that we're supposed to bond neutral and ground in the main panel but can't quite understand what the actual danger/problem with this situation is. This is especially true if the work has been done by homeowners or handy persons. Most of the time grounds and neutrals are not separated in the inside panel. The neutral bar will need to be What Happens When Ground and Neutral Are Bonded? Let’s look at what happens when we incorrectly bond the ground and neutral in a subpanel. Here I bond the neutral and ground together, and also (for example) drive a ground rod and bond both to a grounding electrode. The feeder EGC originates from the main service panel and must land directly on the dedicated grounding bus bar in the sub panel. If you bond them anywhere other than the main service, the neutral return current now has multiple paths, including though your ground wire. There is a sub panel with two large fuses and a disconnect switch after the meter and before the main service panel. Prior to the 2008 NEC that feeder could be 3-wire with the neutral bonded, 2008 and post 2008 code cycles a 4-wire feeder is required. Proper grounding and bonding are fundamental to the safety and functionality of any electrical system. It would be safer to not connect the ground and bond the neutral to the box at the sub panel. The bridge between the equipment grounding bus and the neutral or grounded bus via the main bonding jumper provides: A ground reference to the electrical system’s exposed, non-current-carrying conductive materials. This article will guide you through the importance of a bonding jumper for connecting these two critical parts of your home’s electrical system. But why is this required? Sep 4, 2017 · I have been having a conversation with the local power company over bonding the neutral and the ground in the main breaker panel of a residence. Bond the neutral and ground bars only in the main service panel (not subpanels). This entails two tasks: First, the metal water and gas pipes must be connected electrically to create a continuous low resistance path back to the main electrical panel. Oct 16, 2024 · Bonding at the service panel ensures that all neutral and ground wires connect at a single point, which is crucial for safety and proper electrical operation. that What Is a Neutral Bonding Screw in a Main or Sub Panel Load Center & Should It Be Used or Removed? Dec 20, 2015 · Replaced the old main service panel with a new Siemens main service panel in my workshop. Bonding of the Xo terminal to casing is correct ( neutral/ground bond). The grounded conductors and the equipment grounds are connected to the same terminal bar, contrary to Rule #1. Jul 7, 2019 · The grounded (neutral) terminal bar in a service panel is the heart of an electrical distribution system because it ties together with the equipment grounding conductors (ground wires), grounding electrode conductor (wire to ground rod or other type ground), and the service enclosure (panel box) via the bonding jumper. You are in effect a sub panel. We have to bond these two together so we can complete the return path to the breaker, allowing it to fulfill its protective purpose if there’s a fault. Oct 15, 2022 · I was analyzing the circuit paths and believe that if the main panel is left as-is, but the ATS bonding jumper is removed, since 4 wires connect ATS to main panel and generator, and since the main panel is the only bonding location, it appears that the electrical paths for ground and neutral currents are essentially the same either way. Sep 4, 2009 · I typically have electricians install the ground electrode conductors to the first point of disconnect and bond the neutral to ground for the system there. If your main panel has only a neutral bus that is isolated from the metal cabinet by plastic "feet", then the green screw provided has a place on the neutral bus just for it to be screwed through the bus and into a pre-drilled hole in the cabinet. A common question arises — can neutral and ground be on the same bus bar in main panel? This article explores this question in depth, including when it’s allowed, when it’s dangerous, and why it’s so essential to electrical safety. Jun 21, 2006 · If I bond the neutral and ground in the meter socket (Not a CT meter Socket). This bond should be removed. ) and back to the main panel. The grounding bus bar in the main panel goes to a 5/8 grounding rod at the bottom of the pole. In the meter panel, in most cases, the neutral is already bonded to the can just by how the lugs are attached. The sub panel neutral bar or terminal should not be bonded to the enclosure or the ground of the sub panel. May 21, 2025 · If the main disconnects are in the barn then the feed to the house is a feeder in my view and should be 4 wire 2 hots, neutral and ground unless in metal pipe that can serve as the ground. The NEC allows for any grounding electrode to be connected to the grounding electrode system via the meter socket enclosure. subpanel grounding violations. Jul 11, 2024 · Learn about bonding neutral and ground at the main panel, as well as its importance, benefits, and safety measures. Would you bond the Neutral and ground (Box) the Same as you would bond Neutral and ground at a Main Breaker service. What I can't figure out is why could it be allowed in the first place? What were to happen i May 11, 2020 · In my neck of the woods (Pacific NW) we call that a "class 320" service: A single meter feeding 2 main panels. I don't see the inherent difference between a subpanel and a main panel. The second panel is then fed using four wires, to keep ground and neutral separate. Question is on the MLO (208 side) panel Being served. I also understand why we don't bond neutral and ground in a subpanel but don't understand the problem for keeping them separate in the main panel. With out a doubt it is agreed that when connected to shore power, neutral/ground is bonded at the shore panel, not inside the RV. For the electrical safety reason behind the code requirement, see our blog post Why is it unsafe to bond neutral and ground wiring at subpanels? Feb 6, 2007 · 1) Shore Power. You must also take all grounding Jun 15, 2019 · At the none-fusible disconnect, I bond the EGC to the ground bar and the neutral is isolated and not bonded to the metal or anything. “Bonding jumper” refers to a strap, tie bar or other device that connects the neutral (grounded) conductors with the ground (grounding) conductors. Oct 16, 2024 · Proper Bonding Techniques Bonding Grounded and Grounding Conductors When working with electrical systems, it is crucial to bond grounded and grounding conductors effectively to ensure safety and functionality. Jan 11, 2023 · To my understanding the neutral is to be bonded to grounds only at one location to mitigate objectionable currents. Jun 3, 2019 · This also provides a ground reference for the center tapped neutral to prevent the system voltage floating above ground and creating an unsafe condition if the supply from the transformer grounding point fails, it may be several hundred feet away from the home where the service grounding electrode system is very close to the service panel. At the Main Disconnect the bond screw (Main Bonding Jumper) establishes the fault clearing path downstream, If you were to install an EGC from meter to Main you would have a parallel neutral. Why do we bond at the Service Panel and not at the Subpanels? A very valid and super important question that Dustin brings answers to in the OP, you've got lots of practical advice here, but in a more general sense, keep in mind that "ground" means two things to electricians: earthing and bonding. This is the only point at which the neutral connects to ground. It is a 100 amp 3 wire service with two hots and a neutral. This bonding vs grounding connection allows fault current to return to the source safely, which activates overcurrent protection devices like circuit breakers. Once grounding has been performed and the Main Bonding Jumper has been connected — the grounded conductor (neutral) — which is attached to the neutral terminal bar in the Service Equipment — is also now connected to the: Aug 4, 2020 · I realize that the only time the grounds and neutrals can be bonded is in a main panel, not a sub-panel. I had to remove the bonding screw in the main box, and separate the white and ground wires onto their own bars. Jun 19, 2017 · Bonding and grounding explained All home electrical systems must be bonded and grounded according to code standards. When I started to draw up the subpanel connections, I noticed that the Neutral bar on the Main Panel has Ground connections and the Ground bar has Also see: Bonding Screws vs Bonding Straps (NEC 250. Is that right? Nov 12, 2024 · Yes, in most systems, the neutral and ground are bonded at the main service panel. Dec 4, 2022 · The neutral conductor between the meter and the panel is allowed to bond the various grounding electrodes together. Apr 27, 2024 · But the main panel has the neutral bonded to the enclosure (bonding screw down). May 27, 2015 · The subpanel probably isn't far enough away from the main to require its own grounding rod (s), but regardless, it does require a 4 wire feed from the main panel (2 ungrounded conductors, 1 grounded conductor/neutral, one EGC), and the neutral and grounding buses in the panel must be isolated. MBJ is a very critical piece in the electrical service panel, as it helps provide stable phase-neutral voltage as well as provide low impedance path to ground fault current back to source transformer. Everyone of them had the neutral and ground bonded after the meter base in the enclosure with the main brake, whether the enclosure was right beside the meter base or the main panel. Looking at my main panel, I cannot tell if the neutral is bonded or not. If you cannot lift the bond, disconnect the ground wire to the transfer switch at the generator (or don't run a ground wire at all). ” Bonding is a means of providing electrical continuity between metallic objects. The bonding for the main ground sources such as a ground rod is made at the main panel where all the grounds are bonded together as well. The main Jun 1, 2021 · Here it is: Your ground and neutral wires definitely need to bond (or connect) together. The bottom hole of a receptacle is connected back and bonded at the main panel (and only the main panel) to neutral, so that there is an emergency path for electricity from a broken device or broken neutral back to the utility instead of Jun 8, 2021 · The neutral and ground MUST NOT be bonded at a sub-panel. The meter box will be… Jul 7, 2015 · 1 I had to put a disconnect after my meter, and run 4 cables to my main box. In simple terms, the only place we want to bond the grounds and neutrals together is in the service equipment. 8 Grounding/Bonding The customer shall install the service entrance in such a manner to ensure that all the grounding/bonding requirements of the NEC are met or exceeded. Standard wiring comprises three wires: hot, neutral, and ground. From here I pull 5 wires to the main panel inside/outside the building. The subpanel will still be grounded from the unswitched ground wire from the main panel. The 2 hot wires connect on the disconnect breaker, the neutrals connect on the side of the disconnect breaker. Oct 14, 2023 · Main Bonding Jumper [MBJ] is used to connect switchboard neutral bus and switchboard ground bus. Follow this video to learn what to Jun 22, 2024 · What I understand this to mean is that the neutral and ground should be connected (bonded) in the outdoor panel and usually this is done through a bonding screw that connects the neutral Busbar to the panel box itself. However, in the past the first point of disconnect has always been a breaker in the meter socket or at the main panel. Looks like the neutral is bonded in your main panel, via the bonding screw. 2) Genset Power. ympr ljxkl cyfotc onnw fpcc fdvi ssyd qmgys tnjfyb kkjcw nsluxb jvl zwtlzbi cgym vtyw