125 amp service. For 125 amp wire sizes, the most commonly used wire sizes are 2/0 AWG and 1/0 AWG. It is important to note that the amp wire size also depends on the length of the wire and the type of material it is made from. This wire size calculator will calculate the appropriate wire gauge for a circuit based on amps, voltage, distance, and load. ) So for example with a smart panel, even if you only had a 125A main service you could have an 80 amp charger that mostly runs at a lower power during the day due to appliance use (maybe 16-40 amps) but at night opens up to full 80 amp power when the AC stops running and no one is using the dryer. Table 5. I was thinking 2/0 for the phases. This ampacity also determines how many devices or electrical equipment can you safely use in your house. Basically, you need a 2 AWG copper ground wire for a 200 amp I am in an older home and worried I might be drawing too much power. Jan 20, 2021 · If panel is rated to have 125 amp breakers plugged onto it you could have 15 or 125 amp breaker on every space, or anything in between. However, it is important to follow NEC and local electrical codes for choosing wire sizes for specific applications. Feb 10, 2023 · To my understanding, my main service panel is 125A with a breaker of 100A. Here you input wire length, voltage, and allowable voltage drop percentage, and the calculator will size a 125 amp copper wire size automatically. These wires are able to handle up to 125 amps of electricity, making them suitable for larger electrical loads. 1: Conductor Size for 120/240V, 3-Wire Dwelling Service, Single Phase, From NEC Table 310. The first question is my outside meter has an panel with a 200 amp disconnect inside It. Jul 9, 2020 · Hey guys, Home owners old 100A panel is full and needs to be changed, switching to 125A Panel as my load calc has it pushing the 100A. We need to know your loads to fully help you. That means that you can install a subpanel of up to 200 amps of a 100-amp service. it has nothing to do with the amount of breakers in the panel, if you do load calculations you should never draw more amps than the principle breaker or feeder breaker allows. comProduct description For double pole full size breaker (BR2100R). Answers from Home Alliance Tech Expert: When determining the wire size for a 125 amp service, it is essential to consider the electrical code and regulations applicable to your specific location. I have a couple of questions. May 17, 2004 · Re: 100 amp service to a 125 amp panel A 125 amp rated panel with a 100 amp OCPD as the main and a sub with a 20 or more breakers. Square D Homeline and QO Service Entrance Barriers provide an extra level of safety to installed load centers. We have calculated wire gauges for 125 amp service at 0-500 distance away from the source and for 12V, 120V, and 220V voltages. Quick Wire Size Calculator Oct 9, 2025 · Shop Southwire 2-2-2-4 Stranded Aluminum SER By-the-foot in the Service Entrance Cables department at Lowe's. House sub panel cannot use the typical residential service cable size because inspectors here say it’s not a ‘service’. That’s why it is considered a 200 amp wire. Aug 25, 2020 · The answer is yes you can feed a 125 amp panel with 14 gauge Wire and a 15 amp breaker but that would be silly. For more advanced considerations, use the Wire Size Calculator or the Advanced Wire Size Calculator. He expressed that he didn’t need that sort of capability. May 27, 2023 · For a 125 amp electrical service, there is a need for 2/0-gauge copper wire or a 1/0-gauge aluminum wire. Or more precisely, it’s two legs of 125amps, each at 120V, which when combined adds up 125amps at 240V. Can I run the 4/0 cable from that disconnect to my Jun 17, 2018 · SERVICE SIZE WIRE SIZE 100 amp #2 125 amp #1/0 150 amp #2/0 200 amp #4/0 225 amp #250 The neutral wire is often one or two sizes smaller than the two hots. 125 amps are also ideal for houses with limited electrical appliances. Jul 3, 2006 · Eaton Corporation BR24L125RP Raintight Enclosure - Circuit Breakers - Amazon. 15 (B) (7) and NEC Table 250. Discover the best wire size for aluminum and tips for your project! Apr 10, 2021 · SERVICE SIZE WIRE SIZE 100 amp #4 and #3 125 amp #2 or #1 150 amp #1/0 200 amp #2/0 225 amp #3/0 or #4/0 The neutral wire is often one or two sizes smaller than the two hots. g. Oct 19, 2018 · But 200-amp service is not necessarily the gold-standard for homes, even today. House is wired for 400 amp service. Can I use 100A breaker in Main and run 2-2-2-4 wire to the lugs in the 125A Subpanel? Mar 26, 2021 · House has outside 125 amp disconnect. Aug 20, 2022 · But when it comes to deciding on the proper size ground wire for a 125 amp service, many of us can get confused. My apolgies for mixing terminology. […] THQL21125 2-Pole 125-Amp Circuit Breaker, Repalce for GE 125 AMP Breaker Fit for GE Distribution Panel, Plug-in, 120/240V 50+ bought in past month Add to cart Apr 15, 2025 · Discover the correct wire gauge and code compliance for a 125 amp electrical service. Want 100A delivered to Subpanel 100ft away (run). What Does 125 Amp Service Mean? If you see 125 amps in the panel, your electrical service has a capacity of 125 amps. Accurate service calculations ensure that the system can handle the connected load, minimize risks of overloading, and provide reliable power distribution. Although the NEC recommends using a panel to match the incoming service load, a slightly larger panel is fine, especially if you have plans to add extra circuits. Is there any limit to the number of tandem switches that can be used in one of these panels (e. For residential the minimum required by code (#2's) may be more acceptable. " Your panel can't actually ever see 125 amps, the limit of your service is regulated by the size of it's main (By the meter. I would like to know if it's acceptable to upgrade my 125 amp sub panel to a 200 amp while the main panel remains at 125 amps? Jul 16, 2021 · The service conductors currently support up to 125A. Discover the ideal wire size for a 125 amp sub panel installation. Yes, it is compliant but if you want 200 amps out there later you should make sure you run the appropriate sized conductors for 200 amps. Its a 90' run in underground electrical epvc. A 150 amp panel might only cost $200 or so more, or roughly $1,000 – $1,200. Existing is 3 wire #2 Cu cable so I have to Sep 19, 2024 · Determining the size of your electrical service means finding the amp rating of the main circuit breaker or fuse. My meter is rated at 200 amp. from a 200 amp main panel over to a 125 amp sub panel underground. We can currently upgrade to 125 amp service with no cost from our utility company, but to go to a 200 amp service we will need to trench a couple hundred feet and lay in 3” conduit for the utility to bring in the larger ampacity. 125 amp panel cannot have a 200 amp feeder (service). If you are a homeowner, you will need 100 A and a #1 copper or #1/10 aluminum wire to supply a 125 amp sub panel located within 100 feet. Apr 23, 2016 · A panel with over 125 amp bus will accept the 100 amp or 125 amp QOM2 mains but will not accept a QOM1 main. 125 Amp Wire Size Calculator. However, when you need a 400 amp service or you want to leave room for future upgrades, you might spend $4,000 just for the box and installation. I have a question about grounding a service for a outbuilding. It may only be 125a, but perhaps 150a would also be acceptable, which may be enough for your future expansion needs. A 125-amp panel is large enough for a small home with a few large appliances. As such, I am hoping to have a 200A-bussed panel installed now, that’s protected by a 125A main breaker. What size aluminum wire size do I need. This website provides a wire size calculator, voltage drop calculator, wire ampacity charts and more. Should I run a ground from the meter base into the 125amp main service panel? And at what Jun 30, 2021 · I’ve got a 100 amp main breaker in my center fed panel, and I see that the bus bars are rated for 125 amps. Mar 21, 2024 · I want to install an 18 kw Generac standby generator with 200 amp automatic transfer switch to our 125 amp service panel. Is the 125 amp service panel compatible with the 200 amp transfer switch? Common residential service sizing can be 100a, 125a, 150a, 175a, 200a, and 225a (larger is also available, but I'll stop there). I am running 150 ft. Please help me determine which column to use for my cable size. Feb 1, 2023 · When it comes to wiring for 125 amp service, the size of the aluminum wire you use is important. Its in conduit by the way. He would need an expensive upgrade to be able to realize the full 80 amp charging, and the vehicle to home that the Lightning is capable of. 125A Outdoor use For double pole full size breaker (BR2100R) Use (DS) hub Can be used for service disconnect. So, what if the service is 100 amps, but you have a 125 amp panel? You can use a 125 amp panel for a 100 amp service. Here's how to do it. Seems ok to me but does the main disconnect have to be changed ? swap out the 200 for a 125? . Understand your home’s electrical load with these tips. When it comes to 125 A Motor Disconnect Switches, you can count on Grainger. Conduit for all underground service wires shall be sized with Schedule 40 Gray PVC pipe per Table 5. I added a second panel because I was out of breakers. I don't know where in the code to properly size the neutral but its always 2 sizes down in triplex. My subpanel is 100A. The Square D 125 Amp 16-Space 24-Circuit Outdoor Combination meter Socket and Main Breaker Load Center is suitable for use as a combination service entrance device (CSED). Sep 3, 2022 · Our home electrical panels are only 125 amp service. Sep 19, 2024 · Determining the size of your electrical service means finding the amp rating of the main circuit breaker or fuse. What Size Ground for a 125 Amp Service? When it comes to electrical systems, safety is paramount. I'm running #3 thhn for a 125 amp pool sub panel. com. I realize I'll have to replace my panel and that seems straight forward (find a good electrician and pay him $1500 or so while enjoying the day without power). #2 copper or #1/0 aluminum is good for 125 amp residential service. Shop breaker boxes and a variety of electrical products online at Lowes. The stab limits aren't always clearly defined, sometimes the high amp breaker is built different to reject opposite breaker, sometimes it just seems to be limited by the specific list of This video discusses the decision process of what size gauge wire to use when running a new sub panel from a full breaker box. How do I know if I have 125 amp or 100 amp service? My breaker is rated for 12… Jan 4, 2020 · Service at Main panel is 200A. I was wondering if I could run #6 thhn for the ground and nuetral wires. If you truly need 125 Mar 2, 2022 · If you have a 100-amp service in your home, you can install a subpanel up to double its size. The electrical panel in a home provides the main interface between electrical circuitry and the power company's lead-ins. Mar 11, 2023 · To know what size wire for a 125 amp service, You’ll need to think about the required entire load electrical current, distance, electrical panel capacity, ambient temperature tolerances, and so on. However, it is crucial to adhere to the National Electrical Code (NEC) and local electrical codes when selecting wire sizes for specific applications. 66 Since this is a single phase dwelling service you can use #2 AWG copper or 1/0 aluminum for a 125 amp service or main feeder. That being said, $3000 is absurd on the price unless he's upgrading the main or they're running a long wire. We’ll Search Amazon for your Electrical products such as wire, tools, extension cords, and accessories. In this article, we’ll discuss the grounding requirements for a 125 amp service, including the size of the ground wire and the location of the grounding electrode. Customer: Good morning. The main breaker is 125 amps at 240V, which can handle up to 250 amps at 120V. If you’re a homeowner and need 100A delivered to a 125 subpanel within 100 feet at 75 degrees C, for example, then you’ll need, according to universal This chart displays the size of a ground conductor for a circuit based on the ampere rating of the circuit protection devices. underground feed 100' to pole bdg) planning on aluminim conductors Thinking continuous run of 2/0-2/0-2/0-1. You may want to inquire about what the maximum size your existing underground wires can support. Properly calculating electrical service size is a crucial step in designing and installing an electrical system for residential, commercial, or industrial buildings. Aug 6, 2005 · Re: 125 amp sub panel For commercial, I would go with the #1's assuming the panel has 125 Amp main. I Feb 2, 2025 · What is involved in upgrading to 200 amp service? Read all the vital requirements and considerations like cost, labor, pros/cons, etc. Though if 3 ea. No, you're just feeding a 125 amp panel with a 100 amp meter and service, this is called a "bottom half upgrade. 100 amps X 83% = 83 amps. The 125-amp rating in your panel is an indicator that your panel has the electrical service capacity of 125-amps – which is the total volume of electricity the wires can carry to your home. 310. The wire size requirem Jul 31, 2024 · Can I use the following; 2" PVC conduit buried 24" deep, running (3) 2/0 thhn copper feed cables (double lugged from the 200 amp main service panel) and (1) #6 solid bare copper ground wire into the 125 amp subpanel. We will explain more and provide some helpful hints below. I recommended a DCC load shed device that I had installed for my EV charger. That’s why it’s important to make sure that your grounding system is properly sized for the amperage of your service. Use (DS) hub. Legal with For a 125-amp electrical service, you generally need a 2/0-gauge copper wire or a 1/0-gauge aluminum wire. I have my charger set to start at 10pm, stops at 6am. I need a 4 conductor cable. the other breaker is the vent hood for Nov 21, 2011 · Electrical - AC & DC - Wire size for 125 amp service - I want to run from a meter pole 140' underground to a 125 service panel box. Used to convey power from the service drop to the meter base and from the meter base to the distribution panel board. The most important thing with your subpanel is that it is properly installed with safety in mind. I'm in the design stage of installing solar but I'm planning later in the year to install a heat pump Jan 27, 2023 · If the calculated load is 89A for a condo unit do we need to use 125A main breaker for a new panel provided service wires are big enough or we can use a 100A main braeker panel since the calculated load is less than 100A ? Aug 14, 2023 · Typically, installing a 100 amp panel will cost $800 – $1,000. , Square-D HOM2448M125PC)? The limit on the number of circuits in a panel was removed from the National Electrical Code in Jan 20, 2025 · What size wire for 125 amp breaker? The answer is rarely simple. . You’ll need to take into consideration the required electrical load, distance, space available in the panel, temperature ratings, etc. So am I good to pull 2/0 AL for Apr 28, 2017 · Subpanel install in a pole building. The correct sizing of the neutral depends on doing a calculation of the “unbalanced load,” which is an estimate of the amount of 120-volt current usage. This guide will walk you through the technical aspects, steps, and tools Nov 19, 2023 · If the breaker at the house is 125 amps then a 200 amp main panel will not give you 200 amps. Get expert answers on installing a 125 amp sub panel off your 200 amp main panel. The first I want to upgrade my 125 main in my house to a 200 amp main breaker. Example: A 120/240-Volt, 3-Wire, single-phase electrical service for a single-family dwelling with a calculated load (from Article 220) of 98 amps, supplied by THWN copper overhead service entrance conductors. Question: What size wire do i need for 125 amp service?. This is the best clue from what you have presented so far, what wire size is printed on the wire? #4 copper or #2 aluminum is good for a 100 amp residential service. The sub panel has the 2 pole that I took out of the main panel, 20 amps, and a 50 amp 2 pole for the charger. I’d like to add a 50 amp circuit for EV charging, but my current load calculation is abou The rating of a panel is the rating of the max current feeding into a panel. Oct 10, 2005 · Bought a small house in town (Toledo area) and am doing an update, remodel, etc. Subpanel is 125A. For expert assistance with wire selection and electrical installations, the Electricians Service Team is ready to help. For a small home or condo, 125 amps is adequate; and 150 amps is quite satisfactory for many average size family homes, especially if they have any gas-powered major appliances. Can be used for service disconnect. I foresee a potential need for 200A service in the mid-term future, but do not currently have the budget to pay for a service upgrade in addition to a panel replacement. Wire sizing has me confused a bit here, Can I use existing #2 Cu from meter to panel? Sep 5, 2019 · 125-amp breaker, from pole / main to barn 120'. I purchased a house from someone who had the original panel swapped out a few years ago and I just wanted to see if anyone could tell me the size of my service. Learn about circuit protection and material options. The subpanel will have it's own earth grounding rod also. Perhaps you could give the owner the choice and see if he is willing to pay for the extra "future capacity". I'm learning. Specificity is the key in short. It insulates the always energized lugs when the main is turned off. I used 2-2-2-4 wire from a 200 Amp breaker box to a 125 Amp panel. Feb 8, 2024 · Learn about the process and cost of upgrading to a 200 amp service panel for your home's electrical distribution system in 2024. 1. After all, this is not something that can be left to chance. What size wire would I need to The Homewyse electrical service panel installation calculator uses industry-standard methods and up-to-date cost data to deliver realistic and unbiased estimates. 12 (B) Feeders part. I moved a two pole breaker from the main panel and replaced it with a 50 amp breaker to feed the sub panel. Mar 11, 2006 · On a service panel changeout on 125 amp service where a few more circuits a re needed than the standard panel has may a person use a small 200 amp panel instead to get the added circuits. You can't have total load exceed 125 amp rating of the panel though. Feb 6, 2021 · Hello all. For a 125 amp service, you will need a 1 AWG copper wire or 2 AWG aluminum or copper-clad aluminum wire. Feb 21, 2015 · I see printing. So if the main in the OP's situation has a 125 A QOM2 main - a 150, 175, 200 or 225 will physically interchange with it as they all have same physical dimensions. 125A is the total volume of electricity the bus bars can safely carry. Basically, we are trying to answer what ground wire do you need for 200 amp service. I know minimum size would be 1/0 AL for the phases. Keep me straight. 1/0 will carry the load that More results THQL21125 2-Pole 125-Amp Circuit Breaker, Repalce for GE 125 AMP Breaker Fit for GE Distribution Panel, Plug-in, 120/240V 50+ bought in past month Add to cart Aug 25, 2025 · Is 125 amp service enough for ev charger？ Installing a Level 2 home EV charger usually only requires a 125-amp electrical service, though how adequate this is will depend on your home’s current electrical load, the charger’s specific amperage, and whether load management techniques are used. Apr 19, 2017 · My question is based on the 2008 electrical code. The Wire Size Calculator below will calculate the proper wire size for a circuit based on circuit amps, preferred (or available) wire insulation, conductor type and installation specifications. Wire Size Chart and Maximum Amp Ratings Note: View additional wire size charts from the list below. 180' total (80' from main panel to house wall exit. I looked up the panel and it’s rated for 200amps but the main disconnect has a 125 amp breaker. Can I replace the existing wiring in an 1-1/4" conduit with two copper #2 with a reduced #6 copper neutral using Table 39? Jan 18, 2021 · An electrician can do a calculation, based on the square footage of the house and a list of the installed appliances, to determine the correct size for your main service panel, and it's typical for the total amps of all the breakers to be more than double the rating of the panel and main breaker. Can I use 100A breaker in Main and run 2-2-2-4 wire to the lugs in the 125A Subpanel? Though 200 amp service is considered the standard service for houses with electrical equipment, many people still install 125 amp service according to their needs. If you only want 65 amps yes #6 is ok you can feed a 125 amp sub with a smaller wire size and breaker But more information is needed I don’t know if any residential panels rated for 90c but most are rated for 75c. Feb 4, 2024 · What Size Wire for 125 Amp Service With this 125a wire size and breaker guide, you’ll be empowered to ensure your system is up-to-date and can handle all your electrical needs. Current service entrance is 60 amp with fuses and a gaggle of add ons, subpanels. As for the solar, you may or may not be capable Jan 24, 2015 · Ok to put 200 amp main breaker panel in her condo as sub panel (swap in 125 amp circuit breaker) run from main building breaker panel ( service is 125 amp)? Also, found old AC disconnect all rusted out and 60 amp fuse. Safety features include a main disconnect that trips if the power load exceeds its rating. Jan 4, 2020 · Service at Main panel is 200A. I have been contemplating upgrading my service from 125A to 200A. Each circuit running a 50 amp breaker with #6 wire to each outlet. Here's a guide to help you choose the right size. Basically, your 125 amp panel will be fine and for $3000 he better be doing everything up to code. Find 125-Amp breaker boxes at Lowe's today. Get expert insights on gauge requirements, grounding, and safe practices for your project. Which wire to choose for 100 amp service? According to the 83% NEC rule, a wire for 100 amp service has to handle at least 83 amps (have at least an 83A ampacity). #3 copper or #1 aluminum is good for 110 amp residential service. Nov 10, 2020 · Theoretically speaking, lets say I needed to bump up a service from 100 to 125 amps. Find Sub-panel 125-Amp breaker boxes at Lowe's today. That means that we don’t have to use the 4 AWG wire; we can use the 3 AWG wire because it has 85A ampacity which is higher than the 83A required ampacity. From the Manufacturer Single phase, 3 wire, insulated/bondable movable neutral, 2 (1 Sep 12, 2025 · You don’t need to be an electrician to know how to calculate total amps in a breaker panel. If you consult the copper ground wire size chart above, you can see that you will need a 2 AWG copper ground wire to adequately ground a 250 kcmil wire. A 100 amp electrical service will be used to supply the 98 amp load for the single-family dwelling. Sep 1, 2023 · Learn about the correct 125 amp wire size necessary for generator and sub panel service in your home to meet building code requirements. The 125 amp service will be back to back. 125 Amp Wire Size Charts (2 of them). Supplies and solutions for every industry, plus easy ordering, fast delivery and 24/7 customer support. Feb 19, 2021 · In many 100A+ panels the tabs that the breakers attach to are smaller than the full size of the bussing, and the total amperage of the two breakers attached to each tab can't exceed the rating of the tab. Mar 26, 2015 · Hello everyone. It will have no water supply to this building. They are used for replacement of lost Service Entrance Barriers or additional safety to installed load centers for future maintenance contractors. I have a 100 amp service also. f5focu tuy71pi jjlp il nar85 1rc90 r3gg au w9nf eh7m