Traffic Light Installation Checklist for Contractors: A Practical Guide
A disciplined installation checklist prevents signal failures, site revisits and warranty disputes. Use this field-ready list to plan the survey, foundation, mounting, wiring, testing and handover of a traffic light project.
Common installation mistakes
| Mistake | How to prevent it |
|---|---|
| Reverse polarity on DC heads | Verify with multimeter before power-on |
| Undersized cable causing voltage drop | Use the engineering schedule, not the cheapest cable |
| Missing surge protection | Order it with the cabinet, do not retrofit |
| Earth resistance too high | Drive the earth rod deeper or add a second rod |
| Unlabelled conductors | Label at both ends as you terminate, not at the end |
| Skipped insulation test | Make it a gate: no insulation test, no commissioning |
| Wrong torque on terminals | Use a torque wrench, not a regular spanner |
| Foundation cured too soon | Respect the curing time, even under deadline pressure |
1. Why a checklist matters
Traffic signal installation is unforgiving: the intersection is live, the authority is watching, and any rework costs money and reputation. A structured checklist prevents skipped steps (forgotten earthing, missed cable labelling), captures evidence for warranty and compliance, reduces handover disputes with the authority, speeds up commissioning, and protects the installation team from safety incidents. Always use the same checklist across projects so the team builds muscle memory.
2. Pre-arrival: site survey and drawing review
Before anyone goes on site, the office team completes the following: read the project specification and confirm the scope; review the intersection layout, pole positions and signal head schedule; read the wiring diagram and confirm terminal numbers; confirm the foundation drawings match the soil report; confirm the controller output count matches the signal head schedule; check the surge protection and earthing design; order long-lead items first (custom poles, special heads, large orders); pre-stage labelled cable, glands, terminals and consumables; confirm the site permits and traffic management plan; and brief the crew on safety, sequence and contingencies. A good pre-arrival review prevents 80% of field surprises.
3. Foundation, anchor bolts and cable duct
Foundation work happens first and is the hardest to fix later. For each pole: confirm pole location against the layout drawing (survey marker); excavate to the foundation depth specified in the structural drawing; place anchor bolts on the template, confirming bolt circle and projection; place cable duct (50-100 mm diameter) from foundation to cabinet; place earth rod and earth conductor per the earthing drawing; pour concrete to the specified strength (typically C25 or C30); cure for the specified period (typically 7 days) before loading the pole; photograph and record every foundation before backfill. If a foundation fails inspection, it is faster to redesign than to patch. Always commission the structural engineer sign-off before pouring.
4. Pole, signal arm and signal head mounting
When the foundation is cured, mount the pole and heads: lift the pole onto the anchor bolts, using the template to align; tighten anchor bolts to the specified torque (typically M30 at 800-1000 Nm); check verticality with a spirit level or plumb line; mount the signal arm (if any) per the arm-to-pole drawing; route the head cable through the arm and pole to the cabinet base; mount the signal head on the arm or pole top, tightening all fasteners; mount the visor, backplate and any accessories; apply anti-seize to stainless steel fasteners to prevent galling; confirm drain holes are open and not blocked. Document every step with photographs. The handover package will reference these photos for years.
5. Cabinet placement, surge protection and earthing
The cabinet is the brain. Place it carefully: position the cabinet on the foundation pad or pole base; maintain the required clearance from the kerb, footpath and intersection sight lines; confirm the cabinet door swings clear and the locks work; bond the cabinet to the earth rod with the specified conductor size; install surge protection on the mains input and any external sensor cables; install the controller, conflict monitor, detector rack and power supply; label every conductor at both ends (the cabinet and the field device); and confirm the wiring diagram inside the cabinet door matches the actual wiring. A well-organised cabinet is a long-term cost saver. Spend time here.
6. Cable pulling, termination and labelling
Cabling is where most rework happens. For each run: use the correct cable type and size (UV-resistant, suitable for direct burial or duct); pull cable without exceeding the minimum bend radius; leave service loops at both ends (1-2 m at the head, 1-2 m at the cabinet); strip and terminate to the correct terminal, using the correct ferrule or lug; tighten to the specified torque (typically 2-4 Nm for signal terminals); label every conductor with a heat-shrink or printed marker; continuity-test every conductor before closing the cabinet; and megger-test every conductor to earth (insulation resistance > 1 MOhm). If a test fails, fix it now. Energising an untested cable is unsafe.
7. Testing sequence
Before handing over to the authority, run the full testing sequence: visual inspection (every conductor terminated and labelled, no copper exposed); continuity test (every conductor reads correct resistance end-to-end); insulation test (every conductor > 1 MOhm to earth); earth continuity (cabinet, pole, signal head all bonded and < 1 Ohm to the earth rod); conflict monitor self-test (passes with all outputs off); detector inputs (each detector channel responds to a test pulse); lamp test (energise each output in turn, confirm correct colour at the head); sequence test (run the controller through a full cycle, confirm each phase); UPS or battery test (confirm backup power engages on mains fail); communication test (confirm remote monitoring link if installed); and time and date (confirm the controller clock is correct and NTP-syncing). If any test fails, isolate and fix before commissioning. Do not energise a partial system.
8. Handover, documentation and as-built drawings
Hand over a clean package: updated wiring diagram (as-built) with red-line changes; test results (continuity, insulation, earth, sequence); controller timing plan and configuration backup; equipment list with serial numbers; warranty cards and certificates; spare parts list with reorder contacts; maintenance schedule (lamp replacement, battery test, camera clean); authority training session (1-2 hours with the operations team); and contact list for the supplier, the installer and the authority. A complete handover package protects the warranty and gives the authority confidence to take over the intersection.
Frequently asked questions
What is the most common installation mistake?
Unlabelled conductors and missing earth bonds. Both are easy to prevent but expensive to fix later. Label every conductor at both ends as you terminate it, and verify earth continuity before commissioning.
How long does a typical traffic light installation take?
A single 4-way intersection typically takes 5-10 working days from foundation to commissioning. The foundation cures for 7 days before pole mounting, so plan the schedule to use that time for cabinet preparation and cable pulling.
Do I need a licensed electrician for traffic light installation?
Yes. Traffic signal wiring is mains-voltage electrical work in most jurisdictions and must be done by a licensed electrician following local electrical codes. The cabinet termination, conflict monitor setup and final commissioning are always specialist work.
What tests must pass before commissioning?
Visual inspection, continuity test, insulation test, earth continuity, conflict monitor self-test, detector inputs, lamp test, sequence test, backup power test, and communication test. Any failure must be fixed before energising.
Who owns the as-built drawings?
The contractor typically prepares the as-built drawings and hands them to the authority at project close-out. The authority stores them as the legal record of the installation. GAOQIAO recommends keeping a digital copy with the supplier as well.
How do I handle a project that has changed in the field?
Mark the change on the working drawing immediately (red pen), then transfer to a clean digital copy as soon as the change is verified. Do not energise until the as-built drawing reflects the change. The authority and the supplier both need the final as-built for warranty and maintenance.
What spare parts should I keep on site?
For a typical intersection, keep 1 spare LED module per unique head type, 1 spare controller output fuse, 1 spare surge protection module, 1 spare door seal, and 1 spare lens and visor per unique head type. For larger projects, scale proportionally.
Relevant GAOQIAO products
These public GAOQIAO catalogue pages are related to the guide. Open them for the representative description, then confirm the latest installation procedure before ordering.
- Traffic signal controllersWired and solar controllers with cabinet and installation accessories.
- 300 mm (12 inch) LED traffic lightsStandard heads for urban intersections with full installation hardware.
- Vertical signal poles3-5 m vertical poles for pedestrian and side-road installations.
- Signal arm poles5-7 m signal arm poles for vehicle lane approaches.