What is the wire size for 30 amps 300 feet?

Using the correct size electrical wire for circuits is critical to preventing hazards and preventing fires. This is due to the fact that when power is transmitted over long distances through copper or aluminum wires, voltage drops can occur. Therefore, to ensure safety, you must use the correct wire for your 300 foot chain.

Wait while I show you some calculations and teach you what cable sizes to use for future installations:

How much wire do you need for 30 amps? (80% NEC code)

You must use wire that can handle at least 37.5 amps. So #8 AWG wire that can handle 50 amps is the ideal wire for this branch wire.

I usually use a voltage drop calculator or the National Electrical Code (NEC) criteria for an acceptable 30 amp wire gauge.

**For a 30-amp circuit, you cannot simply use a 30A electrical wire.

You don't even have to use #10 AWG 35A wire. This is because the maximum load for each branch circuit wire is 80% of the circuit current rating for any load. (NEC 220-2)

Pros call it the NEC voltage drop calculator with an 80% power criterion. This indicates that these 30 amps should represent no more than 80% of the rated load of the wire (copper wire or aluminum).

Here's how to determine how much wire of what power you need for a 30 amp electrical panel:

Considering the 80% NEC requirement, I believe that 35A #10 AWG is insufficient. It's almost big enough with 35A, but not quite.

We need a cable that can handle at least 37.5 amps to use a 30 amp switch. The size following the #10 AWG (35A) wire is the size of the #8 AWG (50A) wire.

Thus, the ideal wire size for a 30 amp circuit breaker is #8 AWG wire, which has a current rating of 50 amps.

What is the wire size for a 30ft 300 amp subpanel?

You will need a wire that can handle at least 60 amps.

So using #6 AWG wire that can handle 65A is the best wire for you.

I will teach you how I calculated it below.

A voltage drop occurs when electricity is transmitted over a 30 amp copper wire or 30 amp aluminum wire over a distance. Voltage drop is maintained at less than 3% at less than 10 feet, so you don't have to consider it. (1)

For example, you need to account for voltage drops at 50, 100, 200, or 300 feet. In addition, you adapt to this by increasing the current strength. But how much?

According to NEC 310-16, current must be increased by 20% for every 100 feet from a 30 amp accessory panel.

Simply put, this means that you must:

• Increase the current by 10% for the 30 amp wire 50 feet from the accessory panel.
• Increase amperage by 20% for 30 amp gauge cables 100 feet from the sub panel.
• Increase the current by 40% for the 30 amp wire 200 feet from the accessory panel.
• Finally, increase the amperage by 60% for the 30 amp wire 300 feet from the accessory panel.

The following shows how to determine the power of 30 amps from a distance:

Let's say you need a subpanel 300 feet from a 30 amp mains.

We already know that a minimum of 0 amps of current is required at 37.5 feet. To define an additional 300 feet from the accessory panel, you must increase the current by 20% for every 100 feet of distance. So you have to increase the amperage by 60% to get enough for 300 feet of your circuit.

Therefore, you need a line capable of carrying at least 60 amps for a 30 amp circuit at 300 feet. Unfortunately, #8 AWG wire current is only 50A.

In this situation, choose #6 AWG wire with 65A.

Take a look at some of our articles below.

• What size wire for 30 amps 200 feet
• What size wire for 150 amps?
• Where to find thick copper wire for scrap

Recommendations

(1) electricity - https://www.eia.gov/energyexplained/electricity/

(2) copper – https://www.livescience.com/29377-copper.html