Choosing the right AC size wire usually goes hand in hand with choosing the right AC breaker size. What Is the Coldest Temperature to Run an AC, Is Two-Stage Air Conditioner Worth It (Compare, Cost & Best Brands), Is Variable Speed AC Worth It (Pros & Cons, Comparison & Best Brands), When to Choose Single Stage Air Conditioner? SEER = (1 EER100% + 42 EER75% + 45 EER50% + 12 EER25%)/100, Total Heat (BTU/hr.) Overcurrent protection can be 175% of the value shown in the chart. So, their current-carrying capacity is greater and their voltage drop is lesser. Using 10 guage wire is ok for 20 or 30 amp breaker. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. So, Ive made a wire size chart as well as a guide on how to calculate wire size. 14 gauge. In this case, you should use a 50 amp breaker because it is the next step above the minimum ampacity but still below the maximum ampacity. required amps, you have to consult. Just don't undersize it. Check them out and see which products fit your needs. House needs sided too and thus far 4 have been no-shows/no calls. (Calculated), Best 5 Zone Mini Split Systems In 2023 (Mitsubishi, Carrier, etc. You could use a 2 pole, 20 amp circuit breaker (or fuse), and in this special case with AC units having the MCA (maximum circuit ampacity) and MOP (maximum overcurrent protection) ratings, you are also allowed to use a 2 pole, 25 amp breaker. Single-phase (230 volts) air conditioners use 3 wires only (hot wire, neutral wire & ground wire). According to the chart above, it's clear that a 2-ton air conditioner's capacity is 24,000 BTU, the minimum amp is 13.6, the breaker rating is 20A, and the minimum wire size is 14AWG. For some, thats a new idea that takes a little getting used to. If the wire is not sized properly it will be come a load. http://forums.mikeholt.com/showthread.php?t=162987. By using the maximum current, we are confident that no matter what are the conditions, the performance of the wire is not compromised. If you ever feel overwhelmed or out of depth, consider consulting a professional for more in-depth guidance. Using 10 guage wire is ok for 20 or 30 amp breaker. Rene has worked 10 years in the HVAC field and now is the Senior Comfort Specialist for PICKHVAC. Some FAQs will also be found at the end of this article addressing wiring size. Too large and you risk damaging the equipment with surges and shorts. Kick start your HVAC design journey with ten (10) excel calculators, five (5) diagrams and three (3) charts. Check your ACs installation manual or talk with an electrician to determine the right breaker at the right amps. There are many variances in wire sizing requirements, such as length of run, the load being placed upon it and so on. So, this is how we determine what size wire we need for various air conditioners. Air conditioners do not have a reversing valve. The cost of the wiring is negligible. Assuming you're in the US, the minimum you would need based on the nameplate info would be 12/2+ground (12 gauge wire with 2 conductors and a ground wire). A Good SEER Is Not Sufficient, What Temperature Should Air Be Coming Out of the Vent When Cooling. The BTU ratings are also listed here, if that is how you are trying to determine the wiring size. The correct wire size for any central air conditioner is not determined by voltages, but by the cooling capacity of the system. NM cable would require #12 AWG conductors. The best answers are voted up and rise to the top, Not the answer you're looking for? That breaker would normally be too large for 12 gauge wire, it's only allowed in a case like this where the A/C unit is rated as such. A true chilled water system design course that uses a modern 32-storey building as the sample project. As an Amazon Associate we earn from qualifying purchases. Welcome Tim. From the j-box the 12/2 runs outside . Now that you know a little about wiring air conditioners and heat pumps using the correct size wire and circuit breaker, youre probably wondering: What if I dont do it right? This question is a valid concern for many amateurs working on their homes electrical, so lets take a look. Total Unit Amps Circuit Breaker Amps Wire Size; 0-12 Amp: 15 Amp: 14 Gauge: 13-16 Amp: 20 Amp . Given that information, the main power panel has two separate breakers for the air handler and the other one for the heat pump condenser. Visit https://aircondlounge.com/category/buyer-guide/ to see more guides and product recommendations. A correct time current curve would trip it at most within 5 minutes. (std. You need to use breaker recommended on unit tag. These systems are large users of electricity. If it says 34 amps, like in the example below, we need 8-gauge wire. 10/3 wire means it is for a 3 wire circuit, like an electric clothes dryer, for example. Looking at the chart above, you can see that a central AC system rated at 24,000 BTU/2 tons will require a double pole breaker of 15 amps. sktn77a - Nope.thats exactly the instructions they each gave and is written on the estimate. It's there for a reason. Some of that power is supplied by the battery-like capacitor. 2 Wire size is based on fuse or circuit breaker size. Below, we will go over each of those nine different categories and explain their importance to you and why you would need to have that information on hand in the first place. For example, if a units power needs require you to use an 8-gauge wire, but instead, you use a 12-gauge wire, it can cause severe problems. Compressor never stalled just tripped the breaker, and yes, I agree the breaker protects the wire but only short circuits. With a 18.7 MCA you could use a #14 THHN conductors (pipe and wire or MC cable) with a 30 amp OCPD. So, my circuit breaker current is 55A 80% = 68.75A. As for fan motors and pumps, using the rated current to size wire is usually fine. My Favorite Tool: https://amzn.to/3NIFJuOKNIPEX Cobra Pliers 10": https://amzn.to/3Au0rvxWiha Insulated Screwdriver Set: https://amzn.to/3OJOJ3TTools We Reco. You may want to discuss with your inspector what they expect. Small mini-split systems and window units often require a 15 amp breaker, so a 12-gauge aluminum wire or a 14-gauge copper wire is usually suitable. Depending on the type of aircon, it might draw more Volt-Amps than it does Watts. 16.7 circuit amps I dont have the unit in front of me to see the spec label - just figured they knew what they were using. For a standard 3-ton residential air conditioner or heat pump, you'll need a 20 amp breaker with 12-gauge wire. Pursuit the truth and learn the fundamental ways to approach the chilled-water system. Using a higher gauge wire for an air conditioner or heat pump can be catastrophic, and you should avoid making this mistake at all costs. Youd want to remove the thousands portion of the number and remember that every 12,000 BTU of cooling capacity equals precisely 1 ton. With that said, absolute minimum is a 12gaug or 12/2 (so Hot-Hot Ground) However that assumes everything is 220V, and if the system has 110V anywhere then you might need a neutral. Circuit Breaker Requirements Based On Unit Tonnage, Breaker Sizes for Different Size AC and Heat Pump Units, Air Conditioner and Heat Pump Electrical Wiring Requirements, How to Find Your AC or Heat Pumps Ideal Breaker and Wire Size. For example, if your wiring and unit require you to install a 30 amp breaker, but you install a 20 amp one, it will continuously trip and make using your air conditioner nearly impossible. Using a 30-amp breaker, 80% of the amps are 24 running amps. Some manufacturers include this for both US and Canada. So as @J.Hirsch wrote do it right and safely. In this part of the label, you get told just how many amps will be pulled when you initially start your compressors motor. How to check if an SSM2220 IC is authentic and not fake? How to get from the AC tonnage to the AWG gauge wire choice? You typically measure wire gauge according to the American Wire Gauge, often abbreviated to AWG. Mini-split air conditioners and heat pumps come in various sizes, but you can generally find units between 1 ton (12,000 BTU/hour) and 2 tons (24,000 BTU/hour). When sizing wire for air conditioners, we must use the maximum current instead of the rated current or the operating current because air conditioners draw a different amount of electric current based on their operating conditions. Example: Lets say you have a 3-ton AC unit that runs on a 220V circuit. electrical wiring hvac air-conditioning Share Improve this question Follow asked May 22, 2017 at 15:22 What-About-Bob 427 3 14 21 I might be doing something wrong, but I'm only calculating 12.2 amperes for branch-circuit conductor ampacity. A double pole breaker can handle two 120V circuits, but you use them more often for a single 220V circuit. But in those case of 120 volt loads you mention, the wire matches the breaker. Always check the inside of the wire and not the outside to see past any coating or wrapping. Central air conditioners and heat pumps are some of the largest units that youll find in a residential home. For example, suppose that a units minimum ampacity is 42 amps and its maximum is 60 amps. The exact breaker size you need primarily depends on your air conditioner, so check the requirements usually printed on the compressor unit or consult the table above. It is not used to size the conductors. House is very well insulated. The model number allows us to glean the cooling capacity of this particular heat pump by using two specific numbers located in the middle of this string of numbers. Usually, you can also estimate the SEER rating from the model number. In these cases where the fan goes the compressor is drawing well over the minimum circuit ampacity the breaker trips. What size wire for 30 amp air conditioner? What Size Air Conditioner Do I Need for a 2000 Sq Ft House? Two HVAC contractors who have 30+ years experience want the homeowner to install the electrical wiring! So, the best choice is to use a 15 amp breaker. Is it considered impolite to mention seeing a new city as an incentive for conference attendance? Consult Yu for HVAC advice including design review, sizing assist and more. 12ga will work and is to code, so thats probably what will be used. Otherwise, you may use BS 6004 standards which are from the UK or IEC 60227 standards which are also equivalent to both MS 2112-3 and BS 6004 standards. If the minimum circuit ampacity says 14.9 amps, we're good with 14-gauge copper wire. It's very rare that HVAC contractors are licensed electricians. If they say 20' of 3/8 you can look up the base price of that- and everyone should be scaled by the same amount (Do NOT think you're going to get copper lineset at store prices, not going to happen). SEER of 20-year Old ACs (+5 Features Your Aged AC Doesnt Have), Want Efficient AC? Condensor went, HVAC guy is blaming electrician, is this possible? Mini-split ACs have an outdoor compressor unit and an indoor evaporator unit, with refrigerant and electrical lines running between the two. Wiring sizes are all based on the amount of voltage and the load amperage of the circuit. In what context did Garak (ST:DS9) speak of a lie between two truths? Most mini-split units run on 220V or the equivalent. PickHVAC is also a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com. For instance, if the wire length is extended to 200 meters, the resulted percentage of voltage drop becomes 5.2%. Ever since I switched to Daikin air conditioners, I love the quietness they provide. When wiring your air conditioner, stick with 10/2 for the best results. Smaller 2-ton central units need a 20 amp breaker, while larger 5-ton units often require a 60 amp breaker. We also participate in other affiliate programs which compensate us for referring traffic. Not sure why different electricians are wanting to go with different things, maybe they're trying to future-proof, or they're just going to use what they have in stock. Sizing wire has been a difficult task for many people even engineers. 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