RSA 266:30 Trailer Brakes.

I. No motor vehicle trailer or semi-trailer shall be driven on the ways of this state unless equipped with adequate brakes in good working order and sufficient to control the said vehicle at all times. No house trailer weighing in excess of 1,500 pounds shall be driven on the ways of this state unless so equipped.
II. This section shall not apply to:
(a) A motor vehicle trailer or semi-trailer with a gross weight of less than 3,000 pounds if the axle weight of the towed vehicle does not exceed 40 percent of the sum of the rated axle weights of the towing vehicle.
(b) Wood-sawing machines, log splitters, cement mixers, compressors, tar kettles, conveyors, devices of 2 wheels used by public utilities for the transportation of cables or poles not exceeding 6 in number