Mike, this is the only thing I could find in the Motor Vehicle Rules and Regs for a trailer concerning brakes. No mention on how many axles, etc.
Private utilities, house semi-trailers and trailers:
If the GVWR (including load) is more than 3,000 lbs. or 40% of the towing vehicle's gross weight, the trailer must be equipped with brakes.
Non-conventional vehicles
A non-conventional vehicle is one that is not primarily used for transporting people or property and is only incidentally operated or moved over public roads.
The following is a list of non-conventional vehicles that must be registered but are exempt from titling:
Trailers & Semi-Trailers (Under 2,500 lbs.)
Bogies
Farm tractors (Under 1,500 lbs.)
Snowmobiles and ATVs
Boat trailers (Under 2,500 lbs.)
Folding Tent (pop-up) Trailers.
Mobile construction field offices
Jet Skis