What Size Service Cable For 200 Amp At 400 Feet

200 amp wires are quite big. They can be used as 200 amp ground wires, wires for 200 amp breaker, they tin can be copper or aluminum 200 amp wires. The common question for all these applications here is this:

What size wire do I demand for 200 amp service?

If you wait at the AWG gauge wire chart here, the answer seems to be quite articulate (it'southward not that simple, nevertheless):

Every bit you tin see, the obvious – simply wrong – the choice is using a #000 AWG wire for 200 amp service (also known every bit 3/0 AWG) because it has a 200A ampacity. That, still, will likely end with y'all frying the wire.

For safety measures (in society to avert frying a 200 amp circuit), the National Electric Lawmaking (NEC) dictates the following requirement:

Maximum loading for any branch excursion is 80% of the rating of the circuit for ampacity of wire for any load. (NEC 220-ii)

This is known as NEC lxxx% requirement for wire sizing. In the case of 200 amps breakers, this means you will demand a wire with at least 250A ampacity to connect a 200 amp service.

Looking at the AWG wire chart, yous volition need an even bigger than #0000 AWG wire for 200 amps. You have to become beyond the AWG chart at look at the KCMIL wire chart.

KCMIL wires are bigger and can handle currents of 200 amps and college. Here is a shortlist of KCMIL wires that tin exist used for 200 amps:

250 KCMIL wire with 255A amperage.
300 KCMIL wire with 285A amperage.
350 KCMIL wire with 310A amperage.
400 KCMIL wire with 355A amperage.
500 KCMIL wire with 380A amperage.

The 250 KCMIL wire is the perfect size wire for 200 amp service considering it has 255A ampacity (a minimum of 250A ampacity requirement is satisfied).

Nosotros will prove you how this 250A ampacity is calculated. On acme of that, yous will also need a bigger wire judge if you want to transport electricity 100 feet or 150 feet abroad from sub console (we will show you how to calculate what size wire you lot demand in this case as well).

200 Amp Wire Gauge Calculation: What Size Wire You Need For 200 Amp Circuit?

To fairly determine the 200 amp wire gauge, yous first need to calculate the minimum ampacity requirement as per the 80% NEC rule.

In the example of the 200 amp excursion, here is how the adding looks like (you have to leave 20% extra amps capacity for safety reasons):

200 Amp Wire = 200A × 100% / 80% = 250A Ampacity

That ways that you tin to utilise a wire that has an ampacity of 250A or higher in order to gear up a 200 amp circuit.

As you can see from the listing of KMCIL wires above, the 250 KCMIL wire is perfect for a 200 amp service since it has an ampacity of 255A.

At present, if the sub panel is some altitude away (50 feet, 100 feet, 150 feet, 200 feet, and so on), you will probably have to utilize an even bigger wire to counted the voltage drop.

The NEC 310-16 requirements embrace this nicely:

How To Business relationship For Sub Panel Being 100 Feet Away?

When sending electricity a long way from the sub console, the voltage will drop with the altitude. To counter this drop, you lot accept to boost the initial amps. That means that the circuit has to handle more than amps; in turn, the wire you're using has to handle more amps.

How much more exactly?

Roughly speaking, the NEC 310-xvi requirement states that for a 200 amp copper or aluminum wire, you accept to add 20% to the full amps for every 100 anxiety of altitude.

Example: Let's say you lot want to use 200 amp service 100 anxiety away from the sub panel. Nosotros already know that such a circuit will require wires with at least 250A ampacity. On elevation of this, nosotros have to increase the amps by 20% to get the true size wire for 200 amps at such a distance:

200 Amp Wire (100 ft away) = 250A × ane.2 = 300A Ampacity

Now we have to find a wire with 300A ampacity or more. If you consult the KCMIL listing in a higher place, y'all can run across that the 350 KCMIL wire is perfect for 200 amp service 100 feet away. That's considering it has a 310A ampacity.

You can make a similar adding for l anxiety (10% addition), 150 feet (xxx% addition), and 200 feet (40% improver), and choose the corresponding KCMIL wire.

Hopefully, at present the 200 amp wire sizing is a bit clearer.

You should also wait into different amp wires and like calculations for: