#Wire size for 100 amp electrical panel upgrade

It’s unlikely that you’ll need more than 200 amps unless you have a very large home or run a home business with commercial electrical equipment. If you have a small home or lack large electrical appliances like HVAC systems, you can sometimes use a 100-amp panel without problems. Since 2015, new homes have been built with at least 200-amp service, which is the standard. You can find online calculators to help you come up with a ballpark number, but a more specific figure will require an in-home consultation with an electrician. Your home’s size and electrical needs-referred to as its electrical load-will determine the best amperage for your new panel.

#Wire size for 100 amp electrical panel upgrade

The cost to upgrade your electrical panel largely depends on how many amps you need. What Size Electrical Panel Is Best for Your Home? However, when adding or servicing a 100 Amp wire(s), it is highly recommended to consult and even hire a certified electrician who is aware of local standards and laws regarding electric wiring. So, if You need to know the solid copper wire thickness for 100 Amps service/sub-panel, then: When calculating the wire thickness of the long wires, always use values from the 60☌/140☏ column, since the 'wire length' rule, especially after calculating the '80% Rule' is all about energy losses and not wire surface temperature - as long as the wires are properly installed. Now, we have to check the required AWG value for given wire lengths, depending on the wire surface temperature - values are given in the following chart: Wire Length / Surface feet (125 Amps) There are several rules and standards that may be used when calculating the required wire thickness, but the general rule of thumb is to increase the required Ampacity by 10% for every 50 feet (~15 m) of the wire length - some standards increase Ampacity by 20% for every 100 feet (~30 m) which provides the same or very similar results.įor example, when calculating the required Ampacity for the 50 feet, 100 feet, 150 feet, and 200 feet wires, we can use (default value is 125 Amp, after applying the '80% Rule'):ĥ0 feet wire: Ampacity = 125 Amps * 1.1 = 137.5 Ampsġ00 feet wire: Ampacity = 125 Amps * 1.2 = 150 Ampsġ50 feet wire: Ampacity = 125 Amps * 1.3 = 162.5 AmpsĢ00 feet wire: Ampacity = 125 Amps * 1.4 = 175 Amps 90☌/194☏: 2 gauge wire (AWG 2) features an Ampacity of 130A.Īnd these values are for relatively short wires, usually less than 50 feet (less than ~15 meters), which raises the question about the wire thickness of longer wires. 75☌/167☏: 1 gauge wire (AWG 1) features an Ampacity of 130A, 60☌/140☏: 0 gauge wire (AWG 0) features an Ampacity of 125A,

Thus, for 100 Amp service, the required wire thickness is: Hence, we should not look for wires being able to carry 100 Amps, but 125 Amps: The 80% Safety RuleĨ0% Rule states that actual wire current should be at most 80% of its default Ampacity. 90☌/194☏: 3 gauge wire (AWG 3) features an Ampacity of 115A.īut, these wire thicknesses are not recommended for actual use since wires should never carry current that equals their default values for safety reasons - hence the 80% Rule. 75☌/167☏: 3 gauge wire (AWG 3) features an Ampacity of 100A,

60☌/140☏: 1 gauge wire (AWG 1) features an Ampacity of 115A, Note: Ampacities are given for enclosed wires ambient temperatures.Īs one can see, the Ampacity of wires is given at three different temperatures (60☌/140☏, 75☌/167☏, and 90☌/194☏), but for most residential installations, 60☌/140☏ is the maximum allowed wire surface temperature.Īlso, if the value is not given for a required current, one has to look for a wire with a larger Ampacity.įor example, if we are going to look for 100 Amp wire size using default Ampacities for solid copper wire, then: