what is really *needed* is going to vary on the trailer tow rig combo. A heavy 1 ton tow rig will be able to contol a lighter trailer without brakes, still a good idea to have them though. A lighter rig towing the same trailer, not so much, and brakes would be a necessity.
In BC where I live, I believe it is any trailer over 1500# requires brakes. I am going to be putting them on my M101 CDN2 soon...loaded it is around 1200# and that is a lot on a trail. On the road, not so bad.
It really depends, I am a BIG fan of electric brakes...they work great and stopping my XJ with a 2200-2700# trailer on the back is no harder than without the trailer when the brakes are tuned properly. Had to drive about 30 miles in the rain with a dead brake controller and the loaded trailer, that sucked!! Wont be doing that again.
I don't notice any difference at all with a load of 3000lb. It really depends on what the tow rig has for brakes. If you are towing with an unsuitable vehicle, like a Jeep or a car, God forbid, there is no minimum weight. You should have brakes, period. But, if you are towing with an F250HD or equivalent, the electric brakes won't matter for a trailer and a off road rig on it. Just a distraction, IMO. Of course, if the total towed weight is substantial the brakes are helpful. I will say though that I have seen electric brakes on a trailer overheat in the mountains when the truck brakes were not even working hard. And some guys mess around with the controller when going down a long hill to have the trailer slow things down without using the tow rig brakes (most controllers will let you apply the trailer brakes without pressing on the brake pedal) and that is just a real bad idea. Those little electric trailer brakes are not a substitute for the truck brakes. And applying them by themselves to slow the trailer, load and tow rig is just asking for trouble.
03 Rubicon; 99 xj with too much stuff to list; Unimog 406 (gone)
How big of a trailer can be pulled safely without needing its own brakes? Or maybe how much weight?
The 1500 lb laws are a good guideline to start with, but as has been commented above, the tow vehicle (and it's brakes) have the biggest influence on the decision. Then you have to consider the load inside the tow vehicle.
Assuming you're towing with your WJ, I'd want trailer brakes on anything over 1000 lbs if the WJ is more or less empty. If you're going to put 5 people and gear in the WJ (which could easily be another 1000+ lbs) then I'd want trailer brakes on anything I'd tow.
2006 Black Unlimited 6-speed, Rubicon Express 5.5" Long Arm Kit