In many states trailers with a gross vehicle weight rating of 1500 pounds or greater is required by law to have what equipment

For trailers with weights of 1500 pounds or greater, the law states that an independent brake system should be equipped for that trailer. They should be equipped with brakes which are sufficient to direct the movement of and to stop and hold such vehicle. Brakes shall also be designed and attached such in case of an accidental breakaway of the towed vehicle, the brakes shall automatically apply.

could you go a bit more in depth with you question? it's quite hard to understand. as soon as you do that i will be glad to : )