Learning, Wiring,

What Size Wire for 150 Amp Service (Guide)

Knowing the correct amperage and wire gauge when extending, rewiring, or installing a new circuit is vital. The ampacity is the highest amount that a conductor can undertake consistently under normal operating conditions without surpassing its thermal rating.

In general, the appropriate sizes of wires per amp are the following:

  • A 150 amp circuit requires a 1/0-size copper wire.
  • A 200 amp requires a wire size of 250 kcmil
  • The proper wire size for a 300 amp is 500 kcmil
  • A 400-amp service requires a wire size of 1,000 kcmil
  • Lastly, a 600-amp service requires a wire size of 1,750 kcmil

The amperage that every electrical wire can handle is determined by its components, diameter, and circuit length. Thus, to guide you on installing your wires, we will discuss what size wire for a 150 amp service you need, and we will provide you a table of wire sizes by amp appropriate for your power level.

What Amp Wire Size Do I Need for a 150 Amp Circuit?

The recommended wire size for a 150 amp circuit is a 1/0-size copper wire. Every electric cable installation requires proper wire size. Thus, it is worth a shot to check amp wire size tables to ensure that you select the proper size for your power service capacity.

The larger the cable size is, the more energy and equipment you get. If a smaller than necessary wire size amp is employed, the wire will degrade, and the coating will melt. This is because of the sheer amount of current that flows through it compared to the cable’s rated capacity.

Wire Size Chart

Always remember that electrical wire installation is dangerous and can cause harm or property destruction if done incorrectly. Therefore, it is very important that you select and use the proper sizes for your circuit installation.

To guide you, I prepared an amp wire size table below.

Service RatingCopper ConductorsAluminum
100 Amps#4 AWG Copper#2 AWG
125 Amps#2 AWG Copper#1/0 AWG
150 Amps#1 AWG Copper#2/0 AWG


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Is there a limit on the current that a wire can carry?

According to the National Electrical Code, each wire size, also known as wire gauge (AWG), has a total current limit that it may withstand before becoming damaged. It is critical to select the appropriate wire size to avoid overheating. The number of connected systems to the circuit determines the quantity of current that passes via the wire.

How many amps does a regular house consume?

A 100 amp electrical supply is required in most residences. The National Electrical Code also specifies this as the minimum panel amperage (NEC). A 100-amp circuit panel should be enough to power a medium-sized residence with many 240-volt devices and air conditioning systems. (1, 2)

Take a look at some of our related articles below.

(1) NEC – https://www.techtarget.com/searchdatacenter/definition/
(2) air conditioning systems – https://www.sciencedirect.com/topics/

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About Sam Orlovsky

AvatarCertifications: B.E.E.
Education: University Of Denver - Electric Engineering
Lives In: Denver Colorado

Electrical engineering is my passion, and I’ve been in the industry for over 20 years. This gives me a unique ability to give you expert home improvement and DIY recommendations. I’m not only an electrician, but I also like machinery and anything to do with carpentry. One of my career paths started as a general handyman, so I also have a lot of experience with home improvement I love to share.

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