Wire Size For 30 Amp Circuit Breaker

The nec allows a maximum of a 3 voltage drop on the main branch of a circuit at the farthest outlet of power and 5 total to both feeders and branch circuits to the farthest outlet.

Wire size for 30 amp circuit breaker.

This designation was made specifically for trailers. It uses a 120 volt current. Wire gauge refers the physical size of the wire rated with a numerical designation that runs opposite to the diameter of the conductors in other words the smaller the wire gauge number the larger the wire diameter. The 30 amp is a standard ansi c73 13 tt 30p plug tt 30r receptacle.

If you are going by the nec using a copper conductor at the typical 75f sheathing material rating and using it in an environmentally controlled area then it would be 10awg per nectable 310 16 nec 2008 it s a new table number i. This current must be fused by a 30 amp circuit breaker single pole. Plugs and receptacles are available at lowe s home depot camping world and electric supply houses. For example a 30 amp circuit breaker will trip at 30 amp no matter if is it continuous or non continuous load.

30 amp wire size for a maximum of 30 amps you ll need a wire gauge of 10. Breaker size wire size based on copper thhn wire increase one size when using aluminum conductors at 115 volts at 230 volts 15 amp 14 1 380 2 760 20 amp 12 1 840 3 680 30 amp 10 seldom used on 115 voltage 5 520 40 amp 8 seldom used on 115 voltage 7 360 50 amp 6 seldom used on 115 voltage 9 200 60 amp 6 seldom used on 115 voltage. Calculations the calculator uses the following formulas for calculating wire size which are based on ohm s law. From the chart above a 10 gauge copper wire with an ambient temperature rating of 60 or 140 is seen as standard in most conditions.

These factors are what makes choosing the size of gauge wire to use for a 30 amp breaker not as straightforward as it seems. The most common household item that requires a 30 amp circuit is a central air conditioner often people living in rvs use 30 and sometimes 50 amp systems to run all the appliances in the vehicle. Wire is sized by the american wire gauge awg system. When plugged into a shore power using a single cable an rv turns into a single appliance.

That s why we must select 20 25 higher size of current for circuit breaker than the flowing current in the cables and wires to the connected device.