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Safety Chains and Breakaway Cables

Safety chains and breakaway cables are backups for the day the main connection fails. They only work if they are the right type, attached the right way and in good condition.

What is the job of a safety chain?

A safety chain keeps a trailer attached to the tow vehicle if the coupler comes apart, giving the driver a chance to slow down and stop. It is a last line of defense, not a normal means of towing.

Because of this, a chain should never be used to replace a latched coupler. A trailer connected only by chains is dangerous and should not be moved.

Many farm trailers have seen a lot of years, and original chains may have stretched, rusted or been replaced with whatever was handy. Treat chain condition as part of the trailer's safety, not as an afterthought.

What does a breakaway cable do?

On trailers with brakes, a breakaway cable or switch is designed to apply the trailer brakes if the trailer separates from the tow vehicle. It is a separate system from the safety chains and has its own requirements, battery and attachment point.

Your trailer manual explains how the breakaway system on your trailer works and how to test it. Check with your state, since requirements for breakaway systems depend on trailer type and weight and are set by state law.

If your trailer has no brakes, it likely has no breakaway system, but your state may still have rules about braking on trailers above certain weights. Ask the state patrol or transportation department instead of relying on guesses.

• Safety chain: keeps the trailer attached
• Breakaway cable: triggers the trailer brakes on separation
• Both are backups, not substitutes for a secure coupler

How should chains be attached?

Follow the trailer and hitch manufacturer's instructions. In general, chains are attached to solid points on the tow vehicle, not to the ball or to parts that could separate with the coupler, and they are arranged so that they would catch the tongue if it dropped.

Leave enough slack for turning but not so much that the chain drags on the road. Do not attach chains with improvised hooks or clips. Use hardware that matches the chain's strength and use hooks that close securely.

Chains that are too short can bind in tight turns and pull the connection apart, while chains that are too long can drag and wear through. Check the fit with the trailer connected, and do this on level ground so you can see clearly how the chain hangs.

What should you check on chains and cables?

Look for stretched, twisted or cracked links, worn hooks, rust, damaged latches and cut or frayed cable. Replace a damaged chain or cable instead of repairing it, and replace the whole item if it has been involved in a separation.

Check that the cable is attached in the way the manual describes and that it is not wrapped around a part that would prevent it from pulling free. Confirm that the breakaway battery and switch are in working condition.

How do you build a routine around them?

Make chain and cable checks part of your hitching steps, always in the same order, so that nothing is skipped on a busy day. Connect chains, connect the cable, plug in the lights and test them.

Store trailers so chains are not left in mud or standing water. Keep spare chain hardware you know is rated correctly and replace anything doubtful before you need it.

What if a trailer separates on the road?

Stay calm, ease off the accelerator and brake gradually as your training and vehicle manual suggest. Move as far off the road as you safely can and turn on hazard lights. Do not try to reattach a trailer on a busy roadside.

If anyone is hurt or traffic is blocked, call 911. After an event like this, have the entire hitch system inspected by a qualified shop before towing again, and look for the cause so it does not repeat.

A short recheck of chains after the first mile or so also helps. Vibration can loosen hooks and clips, and finding that in the first minutes is better than finding it at highway speed.

What should every driver on the farm know?

Everyone who hitches a trailer should know why chains are crossed, where they attach and what the breakaway cable does. Take ten minutes to show them on the actual trailer in the yard and let them practice while you watch.

Post a short checklist inside the shop or on the trailer tongue. Include chains, cable, pin, latch, plug and lights, and encourage drivers to speak up when something looks off.

Last reviewed: November 12, 2026. Written by the Farm Safety Editorial Team. See our editorial policy.