Ask MrTruck: 

How Does the Emergency Breakaway System Work? Why Safety Chains?

It may surprise you that the major reason for trailer accidents, is the trailer unhooks because it wasn’t latched or the wrong size ball. Sounds simple enough of a problem and easy to solve, but since we can’t control who tows trailers, it’s a good thing that Emergency Breakaway System is required on trailers that are required to have brakes. In most states that’s a 3000 lb trailer. The majority of states also require safety chains. It’s all designed to stop your trailer if it comes uncoupled from your truck or SUV. Cross your safety chains under the coupler as the chains can “catch” the trailer tongue if it comes unhooked.

The Emergency Brake System is generally located on the trailer tongue. Some trailers have the EBS battery inside away from weather. EBS are required to:

  1. Activates immediately when trailer separates from tow vehicle.

  2. Must bring unhooked trailer to a complete stop and set brakes for 15 minutes.

Adjust the safety chains to hold the trailer first if your trailer comes unhooked, so you can use your trailer brake controller in your cab to slow the trailer down under control. If the safety chains break, then the EBS is designed to stop the trailer immediately at full braking power. At this time, you’ll have no control over your trailer. You’ll be separated from your trailer which is why you need the Emergency Breakaway System to stop your trailer on it’s own.

The cable from the EBS should be attached to the same U-bolts for the safety chains in a gooseneck or receiver safety chain slots or truck frame. A common practice is to weave the cable thru the safety chain with more slack than the chains so the sequence is still chains first, cable EBS trigger second.  Don’t loop the safety cable over the ball. In some crashes, the ball can break and then the EBS won’t engage. The stainless steel cable when pulled, triggers a spring loaded activator releasing 12 volts to the brakes for maximum braking. This electricity comes from a battery in the EBS which on some horse trailers is trickle charged when the trailer electrical cord is plugged into the tow vehicle. If your trailer setup doesn’t charge the EBS battery, then you’ll need to do it a minimum of every 6 months.

The EBS battery needs maintenance like your tow vehicle. A volt meter should show 12 volts on the EBS battery if fully charged. You should test it every 6 months by simply pulling the cable until the brakes engage and pulling forward to see if the brakes are locked up. Reset the pin within a few minutes to keep from running down the battery or damaging the battery. If the EBS doesn’t lock you trailer brakes, trouble shoot to see if the battery is charged and if the trailer brakes are adjusted and working.

If you are in a situation that your trailer unhooks, your safety chains break and your EBS stops your trailer, remember you have less than 15 minutes to block or chock your trailer so it doesn’t roll away when the battery in the EBS is depleted. You don’t want to be chasing your trailer down the on ramp of a freeway.

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