Direct answer: An M19 or M20 3+3 waterproof connector combines three power contacts and three signal or control contacts in one compact interface. The right choice is not based on shell size alone. Select the exact series by rated voltage and current, pin assignment, locking method, cable diameter, installation style, environmental exposure, and the IP rating of the fully mated assembly.
Last reviewed: September 15, 2026
What does 3+3 mean in a waterproof connector?
“3+3” describes a hybrid contact layout: three contacts are normally assigned to power, while three smaller contacts carry control, dimming, feedback, communication, or other low-current signals. Combining both circuits can reduce the number of separate connectors and simplify installation in equipment that needs power and control at the same point.
The notation does not define one universal electrical specification. Contact size, current capacity, voltage, wiring sequence, cable construction, and certification depend on the selected connector family and the approved customer drawing.
M19 vs M20: quick selection comparison
| Selection point | M19 3+3 connector | M20 3+3 connector |
|---|---|---|
| Typical reason to choose | Compact hybrid power-and-signal connection where an M19 interface fits the equipment design | Hybrid connection where the selected M20 series, installation space, or locking style is preferred |
| Locking | Commonly specified with a threaded coupling; confirm the exact series | Available configurations may use threaded or self-locking designs; confirm the exact model |
| Contact layout | 3 power + 3 signal contacts | 3 power + 3 signal contacts |
| Installation | Cable and panel-side options depend on the series | Cable and panel-side options depend on the series |
| Most important checks | Current, voltage, pinout, cable OD, mating geometry, IP condition | Current, voltage, pinout, cable OD, mating geometry, IP condition |
Neither size is automatically better. A connector that fits mechanically but has the wrong contact rating, cable seal, or pin assignment can still fail the application. Start from the electrical load and environment, then confirm the mechanical interface.
Where are M19 and M20 3+3 connectors used?
Outdoor LED and architectural lighting
A 3+3 connector can carry mains or DC power together with dimming or control signals in one waterproof connection. Typical equipment includes street lights, landscape lighting, façade lighting, outdoor displays, and LED grow-light systems. Selected cable assemblies may be configured for 120 V, 230–240 V, or 277 V systems, subject to the approved product specification, wiring diagram, and required certification.
For lighting projects, the signal contacts can be assigned to a customer-approved control interface. RJ11 or RJ14 leads may be integrated on the equipment side when the drawing, conductor size, and control protocol are confirmed. See our outdoor LED and grow-light connector solutions.
Cleaning robots and compact automation
Mobile robots and compact equipment often need motor or charging power plus control, sensing, or interlock signals. A hybrid connector reduces separate connection points, but the design still needs adequate strain relief, repeated-mating durability, vibration resistance, and sealing for the actual operating conditions.
For related integration requirements, review our industrial automation connector solutions.
Seven specifications to confirm before ordering
- Operating voltage: state AC or DC and the maximum continuous and transient voltage.
- Current per power contact: provide continuous current, peak current, duty cycle, and expected ambient temperature.
- Signal definition: identify dimming, communication, sensor, interlock, or other functions and their voltage/current levels.
- Pinout: assign every contact and define protective earth, polarity, and unused positions. Do not rely only on wire colors.
- Cable construction: specify conductor size, number of cores, shielding, jacket material, outside diameter, length, and flexing requirements.
- Mechanical interface: confirm panel cutout, mounting direction, connector gender, locking method, keying, and available installation space.
- Environment and compliance: define the required IP condition, temperature range, UV or chemical exposure, vibration, flammability, and applicable regional standards.
Waterproof rating: what buyers often miss
An IP rating usually applies to a specified, correctly assembled, and fully mated connector system. It should not be assumed that an open connector remains protected when disconnected. If the interface may be exposed while unmated, specify a suitable sealing cap and confirm the rated condition with the supplier.
Cable outside diameter also matters. A seal designed for one diameter range may not seal a smaller or larger cable correctly. For overmolded cable assemblies, cable jacket compatibility, overmolding material, and process control are part of the waterproof design.
Common specification mistakes
- Selecting M19 or M20 only by outside diameter without checking the mating interface.
- Using the total connector current as if every contact can carry the same load.
- Mixing power and signal circuits without a documented pinout and isolation review.
- Assuming “IP67” applies while disconnected or with an unapproved cable diameter.
- Approving a sample without recording cable, terminal, overmold, and test requirements in the final drawing.
How CONNIXTECH supports a custom 3+3 cable assembly
CONNIXTECH supports connector and cable-assembly development from mold and injection molding through cable processing, assembly, and inspection. Our manufacturing site covers approximately 12,000 m², and we have more than 14 years of connector manufacturing experience. Production requirements can include 100% electrical continuity inspection and application-specific waterproof or mechanical tests defined in the approved quality plan.
For faster evaluation, send the mating-side drawing or equipment photo, voltage/current requirements, complete pinout, cable specification, cable length, environmental requirements, annual quantity, and target compliance standard. Browse the threaded M20 connector catalogue or connector product range for related options.
Frequently asked questions
What does 3+3 mean?
It normally means three power contacts plus three signal or control contacts in one connector. The exact electrical ratings and contact functions must be confirmed for the selected series.
Can power and signal share one connector?
Yes, when the connector is designed for a hybrid layout and the ratings, spacing, pinout, grounding, and applicable safety requirements are verified for the equipment.
Is an IP67 connector waterproof when disconnected?
Not automatically. The rating commonly applies when the approved plug and receptacle are correctly assembled and fully mated. Use a rated cap if protection is required while disconnected.
Is M19 better than M20?
Neither is universally better. Choose according to the exact mating geometry, electrical load, cable size, locking preference, panel space, environmental conditions, and certification requirements.
Can the pinout, cable length, or RJ11/RJ14 lead be customized?
Yes. These items can be customized subject to an approved drawing, electrical review, material selection, tooling assessment, and validation requirements.
Request an engineering review
Need help selecting an M19 or M20 3+3 waterproof connector? Send your load, pinout, cable, installation, and environmental requirements to CONNIXTECH. We can review the connector interface and cable-assembly details before sampling.