Quick answer: An M19 or M20 3+3 waterproof connector can combine three power contacts and three low-current control contacts in one lighting cable assembly. An RJ11 or RJ14 lead may be added for a compatible grow-light controller, but neither the 3+3 layout nor the RJ plug defines a universal dimming pinout. Confirm the controller protocol, contact numbering, voltage, cable construction and approved drawing before sampling.
Updated September 29, 2026 · CONNIXTECH application note for outdoor and horticulture lighting engineers.
What does 3+3 mean in a grow-light harness?
In this connector family, 3+3 describes three larger power contacts and three smaller auxiliary contacts. A project may use the power group for the specified supply conductors and the auxiliary group for dimming, sensing or another control function. The actual assignments must follow the equipment maker’s approved schematic. Do not infer live, neutral, protective earth or signal polarity from the connector name, wire color or a photograph.
CONNIXTECH’s M19 versus M20 3+3 selection guide explains the shell and locking choices. This article focuses on the separate question of how to document a lighting harness when an RJ11 or RJ14 control lead is requested.
Engineering specification table
| Item | Specify in the drawing or RFQ | Why it matters |
|---|---|---|
| Connector series and mating side | Exact M19 or M20 model, plug/receptacle, locking type and mating-face drawing | Nominal shell size does not guarantee interchangeability. |
| Power circuits | AC or DC supply, operating voltage, continuous current, protective-earth requirement and each contact number | Power rating and safety review depend on the approved configuration. |
| Auxiliary circuits | Each signal’s function, voltage/current, common reference and isolation requirement | Three auxiliary pins have no universal assignment. |
| RJ lead | RJ11 or RJ14 plug, populated positions, pin numbering viewed from the specified face and controller-side port drawing | A matching plug shape alone does not establish electrical compatibility. |
| Cable assembly | Conductor gauge, jacket material, outer diameter, total length, branch length and strain relief | Sealing and voltage drop depend on the complete harness. |
| Environment | Required IP condition while mated, temperature, UV exposure, washdown and unplugged protection | Protection belongs to a tested assembled interface, not every open end. |
| Validation | Continuity map, insulation and dielectric requirements, ingress test condition and sample acceptance criteria | Tests should match the finished equipment and applicable standard. |
RJ11 and RJ14: confirm the controller interface
RJ11 and RJ14 are commonly used names for modular telephone-style connections, but product naming does not tell a cable assembler which contacts are populated or what electrical signal the grow-light controller expects. Ask for the controller manufacturer’s wiring diagram and a numbered plug-face view. State whether the control interface uses a specified dimming input, communication bus, dry contact or another protocol; do not assume that all RJ-equipped lights share the same wiring.
The drawing should map every circuit from the M19/M20 mating face to its destination, including unused positions. Keep supply power and low-current control definitions clearly separated in the pin-to-pin table. The equipment manufacturer must approve spacing, isolation and regional compliance for the actual supply voltage and installation.
Example pin-mapping worksheet
The following is a blank specification template, not a recommended universal pinout. Fill it using the controller and luminaire drawings.
| Connector contact | Customer-defined function | Destination / RJ position | Wire color and gauge |
|---|---|---|---|
| Power contact 1 | To be confirmed | To be confirmed | To be confirmed |
| Power contact 2 | To be confirmed | To be confirmed | To be confirmed |
| Power contact 3 | To be confirmed | To be confirmed | To be confirmed |
| Auxiliary contacts 1–3 | Each to be confirmed | Each to be confirmed | Each to be confirmed |
Waterproofing the complete assembly
A sealed circular connector and an exposed modular RJ plug have different environmental conditions. If the M19/M20 joint is outdoors, specify the required protection in the correctly assembled and mated state, cable-entry seal and branch overmold. If the RJ end sits inside a dry control enclosure, document that location. If it can be exposed to rain or washdown, the enclosure and lead entry need their own protection strategy; the circular connector’s IP claim cannot be transferred to the RJ end.
Before approving a sample
- Check the plug and receptacle against the approved mating drawing and keying orientation.
- Verify continuity and polarity against the numbered pin-to-pin table, including the RJ viewing direction.
- Verify power-contact current and temperature rise under the intended load and ambient conditions.
- Confirm the controller recognizes the specified control wiring in the actual luminaire.
- Test the mated seal, cable entry and branch structure under the agreed ingress conditions.
- Freeze cable length, jacket, labels and inspection criteria in the production drawing.
Frequently asked questions
Can an M20 3+3 connector carry power and dimming signals together?
A suitable hybrid 3+3 design can route specified power and auxiliary circuits through one connector. The selected model’s ratings, contact spacing, pin assignment and completed equipment compliance must be reviewed before use.
Is an RJ11 lead automatically compatible with my grow-light controller?
No. Confirm the controller protocol, populated positions, pin numbering and signal levels from its documentation. Physical fit is not proof of electrical compatibility.
Can I order a 120 V, 230–240 V or 277 V version?
Project-specific versions may be evaluated, but the exact connector, cable and termination must be approved for the required system voltage and market. State the supply and applicable certification requirement in the RFQ; do not assume one version covers every voltage.
Request a wiring review
Send CONNIXTECH the lighting application, power load, controller drawing, RJ pinout, M19/M20 mating interface, cable gauge and lengths, ingress condition and target quantity. We can review a custom cable assembly against the approved drawing. See our outdoor LED and grow-light connector solutions or request a quotation.