## What Size Wire for 220 Volt 30 Amp? The Complete Guide to Safe and Code-Compliant Wiring
**Choosing the right wire gauge for a 220-volt, 30-amp circuit** is one of the most critical decisions in electrical work. The wrong size can overheat, melt insulation, or cause a fire. The right size keeps your equipment running safely for decades.
### **Why Wire Gauge Matters for 220V 30-Amp Circuits**
Wire size determines how much current it can carry without overheating. A **30-amp circuit** demands a conductor that handles continuous load safely. According to the **National Electrical Code (NEC)**, you also need to factor in voltage drop, ambient temperature, and conduit fill.
### **The Short Answer: 10 Gauge Copper Wire**
For most residential 220V 30-amp applications, **10 AWG copper wire** is the correct choice. It handles up to 30 amps under normal conditions. **8 AWG copper** is required for longer runs exceeding 100 feet to counter voltage drop. **Aluminum wire** would need to be one size larger—**8 AWG aluminum**.
### **NEC Code Requirements You Must Follow**
**NEC 310.16** provides the ampacity tables. At 60°C (140°F) termination rating, 10 AWG copper carries 30 amps. At 75°C, it still carries 30 amps for this circuit size. **Breaker sizing** must match: a 30-amp double-pole breaker protects the circuit. Always verify local amendments, as some jurisdictions differ.
### **Voltage Drop and Distance Considerations**
Voltage drop becomes significant beyond 100 feet. A **3% maximum drop** is recommended for branch circuits. For a 150-foot run at 30 amps, step up to **8 AWG copper**. Use this formula: VD = (2 × K × I × L) ÷ CM, where K is 12.9 for copper.
### **Common Applications for 220V 30-Amp Circuits**
– **Electric dryers** (most common)
– **RV outlets** (NEMA 14-30R)
– **Welding machines**
– **Air compressors**
– **Table saws and large shop tools**
If you’re connecting a plug to this circuit, follow the proper steps for [what size wire for 220 volt 30 amp](https://www.dtcee.com/220v-30-amp-plug-wiring-5-fast-safe-steps-to-connect/) to ensure safe termination.
### **Copper vs. Aluminum: Which Should You Use?**
**Copper** conducts better, resists corrosion, and is easier to terminate. **Aluminum** costs less but requires antioxidant paste and larger gauges. For 30-amp residential circuits, **copper 10 AWG** remains the industry standard. Aluminum 8 AWG works but needs special connectors rated for Al/Cu.
Keyword: what size wire for 220 volt 30 amp
### **Frequently Asked Questions**
**Can I use 12 AWG wire for a 30-amp circuit?**
No. 12 AWG copper is rated for 20 amps maximum. Using it on a 30-amp breaker creates a serious fire hazard.
**What about 10/2 vs. 10/3 wire?**
Use **10/2** for pure 220V loads (two hots + ground). Use **10/3** when you need a neutral, such as for a dryer or range with 120V components.
**Does conduit change the wire size?**
No, but conduit fill rules (NEC Chapter 9) may limit how many conductors fit. Derating applies when more than three current-carrying conductors share a conduit.
**What breaker size for 10 AWG copper?**
A **30-amp double-pole breaker**