gmw photos wrote:
The way I read the DOT requirements for the breakaway cable, it specs the switch must be activated to apply the trailers brakes after the trailer has separated from the tow vehicle. It does not specify "when" in this chain of events. Where the safety chains are presumably keeping the rig together ? Or after a total breakaway ?
Strictly speaking, it "sounds" to me like the reg is saying "after the hitch connection has failed, and also after the safety chain connection has failed".
Right, wrong or otherwise, I have my breakaway cable connected in a way that the pin would only be pulled in the event the safety chains failed, and the trailer is totally disconnected from the truck.
Personally, I would not want the trailer brakes locked and sliding, especially if it happened to be wet pavement, while the trailer is still hanging on by the chains.
YMMV....and your connections may vary as well....
While confusing, this separation or breakaway definition might best be taken understanding that IMO what they are talking about is the "NORMAL" condition with the "safety chains" being just that something that only comes into play in an emergency situation and work in connection with the emergency breakaway switch. If you reread that second link that BarneyS provided along with the links in that quoted link things like what actual manufacturers say on what should happen when, strengths of these often questioned single point attachements for safety chains, how probable it is you can actually "SKID" you wheels from full braking power on a typically loaded full sized TT, etc., etc. are fairly well covered and explained.
Larry