The abbreviation “BC” stands for the term “Bolt Circle” in the lighting industry. All light poles have a circular bolt pattern which is determined by the size of the pole base. This pattern allows contractors to align the anchor bolts in the pole base pattern so that once the concrete has set and the light pole is situated, the bolts will fit perfectly with the light pole base. Most straight anchor rods for the lighting industry are sold with templates that are manufactured to be an exact match to the pole base. This allows contractors an easy installation method for the anchor bolts before the concrete is poured.