How many 1 AWG, XHHW compact aluminum conductors are permitted in a 2 in. rigid metal conduit that is 42 ft long?

To determine how many 1 AWG, XHHW compact aluminum conductors can fit in a 2-inch rigid metal conduit, we must consider the allowable fill capacity as specified in the National Electrical Code (NEC).

First, we need to find the fill capacity of a 2-inch conduit. According to NEC guidelines, a 2-inch rigid metal conduit has a total fill capacity which can be calculated using the conduit fill table provided in the code. For this specific size conduit, the allowable fill for conductors will take into account the conductor's circular mil area.

1 AWG aluminum XHHW conductors have a circular mil area of approximately 8,227. When calculating how many such conductors can fit in the conduit, the NEC specifies that you cannot fill the conduit to more than 40% of its total volume for one or two conductors. For more than two conductors, the allowable fill is lowered to 30% of the conduit’s total area.

The total circular mil area for a 2-inch rigid conduit can be calculated, and from that, the number of conductors that can fit without exceeding the fill limitations can be determined. Following these calculations, it turns out that up to 10 of the