What Size of Wire and Circuit Breaker to Use for 4 ton AC and 5 ton AC?

Installing a 4-ton or 5-ton AC and want to make sure the installation is code compliant, safe and the circuit breaker does not trip?

What wire gauge and circuit breaker should you use then?

Your first stop should always be the nameplate that each manufacturer installs on the condenser unit of the AC.

Check the minimum circuit ampacity rating (amps) and the maximum rating of the circuit breaker or fuse (amps) to guide you on your selection of what wire size to use and the circuit breaker.

This blog post explains how to interpret them and provides some resources to make it easy to select the required wire size too!

Note: The information provided here is only a guide. Always consult the technical specifications section for the manufacturer recommended wire size and circuit breaker rating or contact a qualified installer!

AWG Wire Size for 4-ton AC

Always check the nameplate for the AC or the technical specifications section of the AC as there can be variations in the electrical specifications from one unit to another.

That said, as a rough guide, several 4-ton AC units use the indicative wire gauge to use with a 4-ton AC condenser unit, connected to a 208 -230V single-phase power supply is 10 AWG (10/2) assuming its minimum ampacity rating (specified on its ampacity rating) is 30 amps.

Note: The wire gauge rating assumes a temperature of 75°C.

How to Arrive at 10 AWG wire size?

Look at the nameplate rating of the AC.

Assuming a single phase, 208/230V AC that has a minimum circuit ampacity value of between 27- 28.8 amps, referring to the table Table 310.15(B) NEC 2017, excerpt below, 35 amps is the next standard current listed in the table.

Next, check the column with a temperature rating of 75°C. The recommended conducting AWG size is 10 AWG, in the AWG or kcmil column (see red line).

It is tempting to adjust and use a lower gauge wire that corresponds to the current rating of the circuit breaker (amps), do not.

You can also use the calculator below:

Circuit Breaker Ratingfor 4-ton AC

Use the recommended manufacturer-specified maximum circuit breaker value specified on the AC nameplate.

Several 4-ton AC models may require a 45 amp or 50 amp circuit breaker rating – use what is specified on the nameplate!

AWG Wire Size for 5-ton AC

You may need to use an 8 WG (8/2) or a 10 AWG (10/2) wire depending on the minimum specific circuit ampacity specified on the nameplate of the 5-ton AC.

As a rough guide, if the minimum circuit ampacity (amps) specified is 35 amps or higher, then you should probably go for an 8 AWG wire size.

For minimum circuit ampacity ratings of between 25 -35 amps at 208/230V, go with 10 AWG wire size.

Note: This assumes the conductor temperature of 75°C.

Circuit Breaker Ratingfor 5-ton AC

Use the recommended manufacturer-specified maximum circuit breaker value specified on the AC nameplate.

Several 5-ton AC models may require a 45 amp or 50 amp circuit breaker rating – use what is specified on the nameplate!

Related Questions

1. How Many Amps Does a 4-Ton AC Amp Draw?

The estimated current draw of a 4-ton AC, using a single phase 208- 230V supply is about 21 amps.

This is only rated and the actual current draw depends on whether the is in the initial phase of starting up or later and the current load on the AC.

At startup, the AC’s condenser motors can have a momentary initial current draw several times more than the rated current draw before it reduces to its rated current draw.

2. The Power Consumption of a 4-Ton AC

The estimated power consumption of a 4-ton AC is about 4,800 watts. This is indicative and your AC’s actual power consumption will depend on its energy efficiency rating and the user settings such as fan speed.

You can use a power meter to determine your AC’s actual power consumption in watts.

3. The Cooling Capacity of a 4-ton AC

The estimated cooling capacity of a 4-ton AC is about 48,000 BTU/hr. Refer to the owner manual for your AC model’s cooling capacity.

4. How Many Amps Does a 5-Ton AC Amp Draw?

The estimated amp draw of a 5-ton AC is about 20-25 amps at 208- 230 volts.

The actual amp draw of the AC depends on its energy efficiency rating and user settings selected such as fan speed that impacts its actual amp draw.

5. The Power Consumption of a 5-Ton AC

A 5-ton AC can draw as much as 6,000 watts. Note though that this power draw is indicative and actual power consumption varies depending on the AC’s energy efficiency rating and user settings such as fan speed.

Refer to the owner manual for your AC’s estimated power draw or use a power meter to obtain an accurate reading of its power consumption.

6. The cooling capacity of a 5-ton AC

The estimated cooling capacity of a 5-ton AC is about 60,000 BTU/hr. Actual cooling capacity may vary from one model to another therefore always refer to the electrical specifications section of your AC’s owner manual.

7. Should you use a Dedicated or Shared circuit for a 4-ton and 5-ton AC?

Always use a dedicated electric circuit for your 4-ton or 5-ton AC to avoid the circuit breaker tripping.

8. Wire Gauge and Circuit Breaker Rating (amps) for 1.5, 2, and 3 Ton AC?

The table below shows indicative breaker and wire gauge sizes for 1.5 ton (18,000 BTU/hr), 2 ton (24,000 BTU/hr), and 3 ton (36,000 BTU/hr) air conditioners connected to a 208-230V AC, single phase supply.

Note: This is a rough guide – the actual values that pertain to your particular AC unit might be different. So Always check the electrical data for your specific AC model (nameplate) or contact a qualified HVAC technician.

Final Thoughts

Always consult the nameplate specifications for the minimum ampacity rating (amps) and the maximum overcurrent rating (amps) when selecting wire gauge and circuit breaker ratings for your AC.

The wire gauge should match the minimum ampacity rating (amps) even though the maximum overcurrent rating may be higher.

Do not hesitate to Always consult a qualified HVAC technician. The information provided here is only indicative. Your AC requirements may be different!

Related Topics