If I borrow one of my dads construction trailers to haul something for myself, whos insurance would cover it if something happened? My insurance or my fathers company policy?
Your insurance will. Trailers are generally insured by the company that covers the rig. if he has any sort of business coverage, it might cover it if you damage the trailer, but since it's not being used by the business at the time it's highly unlikely....
That is usually true but wouldn’t it be a shame if he was towing it and something happened and his insurance coverage didn’t apply to the trailer and he was personally responsible? Check you insurance policy, or at the least call your insurance co and ask them. There are many different kinds of insurance policies and different restrictions and exclusions that might not provide coverage to a trailer. More likely than not there would be coverage but i would check just to make sure. Remember there is no such thing as "full coverage".