Published 2026-10-16 · Ride On Rentals, Delta BC
The two backup systems on every trailer hookup, what BC law requires of each, and how to check them in the yard before you pull out.
A trailer hookup has one main connection, the coupler on the ball, and two backups behind it. The safety chains are there to keep the trailer attached if the coupler lets go. The breakaway cable is there to stop the trailer if everything lets go. Both take about a minute to set up properly, and both are easy to get slightly wrong. This guide covers what BC law says about safety chains and breakaway cable, how to rig them, and how to test them before you leave the yard.
The rule is in section 7.07(1) of the Motor Vehicle Act Regulations. You can't drive a vehicle and trailer on a highway unless, among other things, "the vehicles are equipped and connected with an auxiliary coupling device with a breaking strength of not less than the gross weight of the vehicle or vehicles being towed." The only exception is a fifth wheel and kingpin on a semitrailer.
The Commercial Vehicle Safety and Enforcement branch says the same thing in plainer words in its Trailer Towing info sheet: your vehicle must be "equipped and connected with an auxiliary coupling device consisting of a chain or metal cable equal in strength to the principal coupling device." Its fact sheet MV3230 adds that "all vehicles being towed via a ball hitch must have safety chain(s) or cable(s)."
Read the two ratings that matter. The coupler on the trailer tongue is usually stamped with its capacity. Safety chains usually carry a tag or stamped grade. Under the regulation, the chains have to be able to hold at least the gross weight of the trailer and its load. Under CVSE's wording, they should match the coupler. If a chain has no readable rating, or a link is stretched, bent or gouged, it is not doing its job. Tell us at pickup.
Do it in this order, after the coupler is latched and pinned on the ball.
If the coupler pops off the ball, the tongue drops. Crossed chains form a cradle under the coupler that can catch the tongue before it hits the pavement and digs in. Chains run straight back from each side can't do that. A tongue that digs in at speed is how a minor coupling failure becomes a crash.
A breakaway device is a switch on the trailer tongue with a pin attached to a cable. On a trailer with electric brakes, the switch is wired to a small battery on the trailer. If the trailer separates from the tow vehicle, the cable pulls the pin, and the switch sends battery power straight to the trailer brakes, locking them on.
The CVSE fact sheet is direct about when you need one: "Every trailer with brakes must have a breakaway device hooked to the trailer brake system." Whether a trailer needs brakes depends on its weight. Our guide to BC trailer brake requirements walks through the 1,400 kg and 2,800 kg thresholds.
For commercial trailers, section 6.07 of the regulations goes further: the brakes must apply automatically on separation and "remain fully applied for not less than 15 minutes." That is why a breakaway battery that has gone flat is not a small problem.
The cable has to pull the pin when the trailer leaves the vehicle. So it must be anchored to the vehicle, with a little slack for turns:
ICBC's pre-trip inspection includes a breakaway test. In short form:
Don't leave the pin out longer than you need to. On electric brakes, the switch is feeding the brake magnets straight from the trailer battery the whole time.
ICBC also warns that the breakaway device "is meant for emergency use only. Do not use it as a parking brake." To park a trailer on a slope, chock the wheels.
| Mistake | Why it matters | Fix |
|---|---|---|
| Chains hooked straight back, not crossed | No cradle to catch the tongue | Cross them under the coupler |
| Chains dragging on the road | Wear, sparks, weakened links | Twist to shorten, keep enough slack to turn |
| Chains hooked to the bumper or tie-down loops | Those points may not be rated for a trailer's weight | Use the hitch's safety chain loops |
| Breakaway cable clipped to a chain | Cable may not pull the pin in a full separation | Anchor it to the vehicle on its own |
| Breakaway cable too short | Pin pulls on a tight turn and locks the trailer brakes | Leave turning slack |
| Never testing the breakaway | You find out it doesn't work when you need it | Pull-pin test before each trip |
Check that your hitch receiver has safety chain loops in good shape and an obvious spot for the breakaway cable. When you book, tell us your tow vehicle and we will confirm compatibility and any hitch or wiring needs. Our trailer ball size guide covers the coupler side of the connection, and the hitch classes guide covers the receiver. Questions about a specific trailer's chains or breakaway setup? Call (604) 767-7977.
Section 7.07 of the Motor Vehicle Act Regulations requires an auxiliary coupling device with a breaking strength of not less than the gross weight of the vehicle being towed. CVSE puts it as a chain or metal cable equal in strength to the main coupling device.
Yes. ICBC's towing guide says to cross the chains over each other, under the ball and hitch. The crossed chains form a cradle that can catch the trailer tongue if the coupler comes off the ball.
To the tow vehicle, on its own attachment point. ICBC's hookup steps say to secure the breakaway switch cable to the tow vehicle. Don't clip it to a safety chain or the hitch ball, because the point is that it pulls the pin when the trailer separates from the vehicle.
Every trailer that has brakes. The CVSE fact sheet MV3230 says every trailer with brakes must have a breakaway device hooked to the trailer brake system, so it applies the brakes if the trailer separates from the tow vehicle.
No. ICBC says the emergency breakaway device is meant for emergency use only and should not be used as a parking brake. Chock the trailer wheels instead.
Questions about a rental trailer? Call Ride On Rentals at (604) 767-7977 or email [email protected].