Is 14 2 wire OK for garbage disposal?

Quick Answer

The quick answer is that 14/2 wire can be used for garbage disposals, but 12/2 wire is recommended. The National Electrical Code requires a dedicated circuit for garbage disposals with a minimum of 15 amp capacity. While 14 gauge wire is rated for 15 amp circuits, 12 gauge wire is better suited for the power demands and longevity of a garbage disposal. Using 12/2 wire provides a higher ampacity and reduces voltage drop compared to 14/2 wire.

What Size Wire is Required for a Garbage Disposal?

The National Electrical Code (NEC) specifies that garbage disposals must be installed on a dedicated circuit with a minimum of 15 amp capacity. This means the circuit breaker servicing the disposal should be 15 amps, and the wiring used must be rated for 15 amp circuits.

The most common wiring used for 15 amp circuits is:

• 12 AWG copper wire
• 14 AWG copper wire
• 12 AWG aluminum wire

Of these, 12 AWG copper wire is the recommended wiring for garbage disposals. Here’s why:

12 AWG Copper Wire

12 gauge wire has a higher ampacity (20 amps) than the minimum 15 amp circuit required for disposals. This gives a safety margin and reduces voltage drop compared to smaller 14 gauge wire. The thicker 12 gauge wire is more durable and better able to withstand heat and voltage spikes that can occur with garbage disposals. This helps prevent fire hazards and electrical issues down the road.

14 AWG Copper Wire

14 gauge wire is rated for 15 amp circuits, so it meets the NEC requirements for disposal circuits. However, it has less capacity and higher resistance than 12 gauge wire. This can lead to more voltage drop and power loss during start-up and operation of the disposal. The thinner wire is also more susceptible to overheating with the repetitive motor start-ups required by disposals.

12 AWG Aluminum Wire

Aluminum wiring is allowed, but not recommended, for disposal circuits. Aluminum has higher resistance than copper, so it’s more prone to voltage drops, overheating issues, and connection failures. These factors make copper wire the better choice. If aluminum wire is used, it’s important that special precautions be taken with connections and anti-oxidant paste.

Key Reasons to Use 12/2 Wire for Garbage Disposals

Here are some of the main benefits of using 12/2 wire instead of 14/2 wire for garbage disposals:

Higher Ampacity

– 12 gauge wire has an ampacity of 20 amps, while 14 gauge wire is only rated for 15 amps. This gives a safety margin and reduces risk of overheating.

Lower Voltage Drop

– The lower resistance of 12 gauge wire results in less voltage drop. This helps maintain full power to the disposal motor.

Handles Power Surges

– The thicker 12 gauge wire is better able to handle current spikes that can occur when a disposal starts up or jams. This reduces fire hazards.

Longer Lasting

– The durability of 12 gauge wire makes it more resistant to heat damage and fraying over time. This increases safety and service life.

Reduces Tripped Breakers

– By reducing voltage drop and handling surges better, 12 gauge wire cuts down on nuisance breaker tripping.

Is it Allowed by Code to Use 14/2 Wire for Garbage Disposals?

The National Electrical Code permits 14 gauge wire for 15 amp circuits, including garbage disposal circuits. So 14/2 Romex cable meets the minimum NEC requirements for disposal wiring.

However, the code does not preclude the use of thicker 12 gauge wire. It simply establishes the minimum wiring size. And 12 gauge wire is generally recommended as a better choice for disposals.

Some additional points on using 14 gauge wire for disposals:

– Keep wire runs as short as possible to minimize voltage drop.

– Use dedicated circuits only – no other outlets or loads.

– Use a 15 amp GFCI breaker for overload protection.

– Address any tripped breakers or overheating issues by upgrading wiring.

So in summary, while 14/2 wire is compliant with code for disposals, 12/2 wire is the preferred size for optimal safety and performance. The few extra dollars spent up front can prevent problems down the road.

Should a Dedicated 20 Amp Circuit Be Used?

Garbage disposals are required by the National Electrical Code to have a dedicated circuit, but the minimum capacity is 15 amps. However, there are some good reasons to consider installing disposals on a dedicated 20 amp circuit instead:

Added Power Capacity

A 20 amp circuit provides more power capacity than a 15 amp circuit. This gives a safety factor if the motor demands spike for any reason or if an overload occurs.

Allows Use of 12 Gauge Wire

Increasing to a 20 amp circuit allows the use of 12 gauge wire. As discussed earlier, 12 gauge wire is preferable for disposals due to better heat tolerance, lower voltage drop, and higher durability.

Accommodates Larger Disposals

Larger capacity disposals over 3/4 HP are more likely to require the extra power capacity of a 20 amp circuit. This prevents nuisance tripping.

Safety Factor for Older Homes

Older homes with outdated, spliced, or undersized wiring especially benefit from the extra capacity of a 20 amp disposal circuit.

Resale Value

A 20 amp disposal circuit provides safety and convenience for future homeowners. This is a selling point for resale value.

The main downside is the added cost of installing a 20 amp breaker and 12 gauge wire. But this is usually worth the safety and performance benefits for a key kitchen appliance like a garbage disposal.

Cost Comparison of 12 vs 14 Gauge Wire

The cost difference between 12 and 14 gauge wire is relatively small. Here is a comparison of 100 feet of 12/2 and 14/2 NM cable from Home Depot:

12/2 NM Cable

– Cost for 100 ft: $72
– Ampacity: 20 Amps
– Diameter: 0.205 inches

14/2 NM Cable

– Cost for 100 ft: $58
– Ampacity: 15 Amps
– Diameter: 0.180 inches

The 12 gauge cable costs about 20% more than 14 gauge cable per foot. However, 100 feet of wire contains enough length for most disposal circuits. On a typical 30 foot disposal circuit, the upgrade to 12 gauge only costs about $5 more.

This relatively small incremental cost is worthwhile to gain the advantages of lower voltage drop, higher safety factors, reduced tripping, and increased durability. The total cost difference for an entire disposal circuit upgrade is likely less than $10 in most homes.

Voltage Drop Comparison of 12 vs 14 Gauge Wire for Garbage Disposals

Voltage drop refers to the loss of electrical power that occurs as current passes through a wire. Thicker wires have lower inherent resistance, and therefore less voltage drop. Here is a voltage drop comparison of 12 vs 14 gauge wire for a typical 30 foot disposal circuit with a 1/2 horsepower motor drawing 5 amps:

12 AWG Wire

– Resistance per 1000 ft: 1.588 ohms
– Resistance for 30 ft: 0.047 ohms
– Voltage drop: 0.047 * 5 = 0.235 volts

14 AWG Wire

– Resistance per 1000 ft: 2.525 ohms
– Resistance for 30 ft: 0.075 ohms
– Voltage drop: 0.075 * 5 = 0.375 volts

For this sample circuit, the voltage drop with 14 gauge wire is 0.375 – 0.235 = 0.14 volts higher compared to 12 gauge wire.

While less than 1 volt, this increased voltage drop with 14 gauge wire results in more power loss and reduced efficiency. Over time, the higher resistance leads to more waste heat production in the wiring.

The thicker 12 gauge wire keeps voltage drop low, even with longer wire runs. This maintains full motor power and reduces fire hazards.

When Should a Separate Neutral Wire Be Used for Disposals?

Garbage disposals normally utilize the shared neutral wire in a standard NM cable like 14/2 or 12/2 Romex. However, a dedicated neutral is recommended in certain circumstances:

– Very long wire runs – A separate neutral prevents overloading when voltage drop is a concern.

– Commercial settings – Helps prevent tripping with larger motors and heavy use.

– Older wiring – Upgrading an old circuit may benefit from a separate neutral.

– Shared circuits – If code requires a shared neutral on the disposal circuit, isolating the neutral can avoid interference.

– Troubleshooting – Sometimes a dedicated neutral will resolve tripping or voltage drop issues.

– Electrician preference – Some electricians install separate neutrals by preference on certain major appliances.

In most typical residential settings with newer wiring, the shared neutral wire in Romex cables is sufficient. But an electrician may advise using a dedicated neutral in specific cases where voltage drop, overloading, or interference on a shared neutral may occur. This provides optimal safety and performance.

Conclusion

While 14 gauge wire meets the NEC minimum size for garbage disposal circuits, using 12 gauge wire is highly recommended. The thicker 12 gauge wire provides the following benefits:

• Lower voltage drop
• Increased ability to handle inrush currents on start-up
• Better resistance to overheating with repetitive motor cycling
• Increased durability and life span
• Higher safety factor

The slightly higher cost of 12/2 Romex cable compared to 14/2 is well worth it for a critical kitchen appliance like a garbage disposal. It can prevent nuisance circuit tripping, power loss, overheating fires, and other issues. For optimal safety and performance, always follow the recommendation to use 12 gauge wire for garbage disposals whenever possible.