If there was a large tank or generator or a pump or whatever mounted on the wood floor of the panel, those braces went under the wood floor to help support the item and then attached to the frame. It was made by the outfitting company that installed the equipment. I found those braces under a 1 ton panel I did some chassis work on. It originally had something like a generator in it from the Gulf Oil company. Look in the gallery under 47.2 Chevy's. It's Brad Birdnow's panel,
Scott
