That's interesting... although it doesn't specifically say wether or not a 3,000lbs trailer has brakes, Pa. Code online says the following:
§ 175.4. Vehicles required to be inspected.
A registered vehicle moved upon a highway shall bear a valid certificate of inspection
except for the following:
(1) Special mobile equipment.
(2) An implement of husbandry.
(3) A motor vehicle being towed.
(4) A motor vehicle being driven or a trailer being towed by an official inspection station owner or employee for the purpose of inspection.
(5) A trailer having a registered gross weight of 3,000 pounds or less.
(6) A motorized pedalcycle.
(7) A vehicle being repossessed by a financer or collector-repossessor through the use of miscellaneous motor vehicle business registration plates.
(8) A new vehicle while it is in the process of manufacture including testing, and not in transit from the manufacturer to a purchaser or dealer.
(9) A military vehicle used for training by a private, nonprofit, tax-exempt military educational institution when the vehicle does not travel on public roads in excess of 1 mile and when the property on both sides of the public road is owned by the institution.
(10) An antique vehicle.
You can find it at this link...
http://www.pacode.com/secure/data/06...75/s175.4.html