When I worked at Siemens, I was responsible for Power, Control and Distribution components as sold through traditional electrical distribution supply houses, in the cubicle right across from me was Kelvin, my counterpart responsible for products going to retail outlets like HD and Lowes (no controls though). The components, like breakers, panels, disconnects and such, were EXACTLY the same; there were no "cheaper" versions. But the thing was, the VOLUME ordered by HD was on a scale unheard of by the average local supply house. So for example a good month for me on QP single pole 15 and 20A breakers through the 20 or so supply houses I supported was maybe 1,000 breakers total, whereas Kelvin would take orders from just the local HD logistics center, servicing maybe 50 HD stores, for 10,000 1P breakers even on a bad month. The pricing he was allowed to use for HD was therefore WAY lower than the best pricing I could offer the supply houses, but it was all based on volume. I had one supply house bring me a project that involved 20,000 1P breakers, I got better pricing negotiated as a one-shot deal from the factory than he ever did. There were other issues too, for example he could only sell them General Duty safety switches, I could sell GD or Heavy Duty versions (at that time, it may have changed now because I saw an HD rated switch at Lowes a while ago). On the other hand, Siemens did allow HD to put together custom "retail packages" that the supply houses could not order, like the meter-main combos. So those had special part numbers exclusive to HD and if a contractor called a supply house to cross check prices, the supply house could not do it by part number.
