A waterproof splice connector joins two wire ends inside a sealed assembly. The most durable kind is the enclosed-housing type — a rugged IP-rated shell with a gland cable entry and reopenable screw terminals — rated IP67 for above-grade joints and IP68 for direct burial or immersion. With no soldering or special tools, it gives a field-serviceable, sealed joint that survives water, UV, and temperature cycling far better than heat-shrink or tape.
Has a yard-light run gone dark after a rainy season? Has a buried garden-pump feed started tripping its breaker after a few months, the heat-shrink joint already corroded inside? The fault is rarely the wiring craft — it’s the connector. An enclosed-housing waterproof splice connector seals the whole joint in a hard shell, so it shrugs off the immersion, UV, and freeze-thaw that destroy taped or shrink-wrapped splices.
What Is an Enclosed Waterproof Splice Connector?
A waterproof splice connector mates two cable ends in one component. An open crimp butt terminal offers very limited protection; an enclosed-housing waterproof splice connector instead seals the entire joint inside a rugged shell — usually flame-retardant PA66 nylon — using an IP-rated gasket, a cable-entry grommet (gland), and internal terminals. The shell acts as a second line of defense when the primary gasket ages.
One detail many installers miss: per Amphenol LTW’s waterproof connector guidance, an IP rating is only valid when the connector is fully mated — an unmated open end still exposes bare contacts to moisture, even on an IP68 housing. Its core advantages over heat-shrink:
- Hard shell — prevents the cracking that crushes heat-shrink tubing during burial.
- Gland entry seal — forms a ring seal around the cable jacket across a typical 4–12 mm OD range, regardless of wire size, much like a dedicated waterproof cable gland.
- Serviceable interior — screw terminals let you reopen and rewire without cutting the cable.
This enclosed splice format belongs to the broader waterproof electrical connector family, but it should be selected only when the project needs a sealed fixed joint rather than a reusable plug. For connector-family routing, see the waterproof electrical connectors guide.
If you need a connection you can unplug for service rather than a sealed permanent joint, see our waterproof plug connector guide instead.
IP67 vs IP68: Which Rating Do You Need?
The IP system is defined under IEC 60529:
| Rating | Liquid test condition | Typical application |
|---|---|---|
| IP65 | Sustained water jets from any direction | Outdoor floodlights, wall sconces |
| IP67 | Immersion at 1 m for 30 minutes | Landscape lighting, garden fixtures |
| IP68 | Continuous submersion >1 m (maker-defined) | Pool lights, direct burial, fountains |
| IP69K | High-pressure, high-temperature washdown | Food processing, car-wash gear |
For low-voltage DC selection such as 12V / 24V lighting, RV, vehicle accessory, or small pump wiring, see the waterproof 12V connector guide. For landscape-lighting applications specifically, see the waterproof landscape lighting connectors guide.
For the full connector-type and IP-rating overview, see our waterproof connector types & IP ratings guide.
5 Specs That Decide Long-Term Reliability
Not every enclosed waterproof splice connector lasts; these five specs predict which will:
- Shell material — PA66 vs PVC. UV-stabilized PA66 nylon handles sunlight, impact, and −40 °C to +105 °C. Standard PVC turns brittle below −15 °C and softens above 70 °C, so PA66 is mandatory for sun-exposed or freeze-thaw sites.
- Contact material — tinned copper or brass. Bare copper corrodes in damp soil within 12–18 months; tinned copper or brass resists galvanic corrosion. Look for contact resistance under 5 mΩ at rated current and at least 500 mating cycles.
- Current and voltage rating. Consumer landscape connectors run 10–24 A at 300–450 V AC; industrial outdoor power connectors reach 32–50 A. Per NEC 210.20(A), the connector should be rated at least 125 % of the circuit’s maximum load current.
- Gland (cable-entry) range. A gland sized for 6–11 mm cable OD covers most 12–6 AWG (2.5–16 mm²) outdoor power cable. A mismatched gland is the single most common cause of IP68 failure, because water then wicks along the jacket into the terminals; our cable gland IP rating guide explains matching the gland to the cable.
- Triple-seal design. Top IP68 parts use three barriers — a front mating-face seal, a rear gland seal, and an internal terminal barrier — so the joint stays dry even if rough handling or ground settling damages one seal.
Where Enclosed Waterproof Splice Connectors Are Used
The enclosed waterproof splice connector serves four power-critical fields:
- Outdoor and architectural lighting — LED garden, path, and façade fixtures in irrigation zones and green roofs increasingly require ≥IP67 sealed power joints, and a properly installed buried splice is built for many years of outdoor service.
- Solar and EV-charging infrastructure — ground-mount PV runs multi-core cable across uneven terrain, where IP68 enclosed splices protect mid-run joints from seasonal pooling; outdoor EV chargers face condensation, washdown, and freeze-thaw too.
- Marine and poolside wiring — marine housings should pass salt-mist testing (IEC 60068-2-11) and meet IP68; pool-edge circuits run at ≤12 V DC or 120 V AC on GFCI, so confirm the connector’s voltage rating matches.
- Industrial outdoor equipment — farm machinery, CCTV poles, and traffic cabinets expose power joints to mud, high-pressure spray, and vibration, where enclosed IP68 splices far outperform taped crimp joints. See Verchil’s outdoor industrial solutions and, for multi-circuit power, our heavy duty connector range.
For gel-filled DBY connectors, heat-shrink butt splices, sealant wire nuts, self-fusing tape, and other outdoor packaged wire-connector options, use the outdoor waterproof wire connectors guide. This page focuses only on enclosed IP68 splice housings with cable glands and internal terminals.
How to Install an Enclosed Waterproof Splice Connector
Correct installation is what turns an IP68-rated part into actual IP68 protection:
- Strip cleanly — 8–10 mm of insulation, no more; excess bare conductor raises arc risk inside the shell.
- Match the gland insert to the cable OD — a loose gland breaks the seal at the entry, the most common install error.
- Land the conductors — for screw terminals, torque to spec (typically 0.5–0.8 N·m for 2.5 mm² conductor).
- Verify continuity with a low-voltage tester before closing the cover.
- Apply dielectric grease in the gland seal and terminal cavity for buried or submerged installs.
- Torque the housing fasteners to the printed spec — too tight crushes the gasket, too loose leaves a gap.
- Confirm burial cover before backfilling — do not use one universal burial depth for every outdoor power circuit. NEC 300.5 cover requirements vary by wiring method, voltage, GFCI protection, raceway type, and location. Follow the project code requirement, the cable listing, and the connector datasheet before direct burial. For wire fit, wicking, and corrosion diagnosis, see the waterproof wire connectors guide.
Conclusion
Choosing the right waterproof splice connector comes down to three decisions: match the IP rating to real exposure (IP67 for above-grade rain, IP68 for burial or immersion), pick the shell material for your temperature and UV conditions (PA66 over PVC), and choose the terminal type for serviceability. Across long-term outdoor power applications, an enclosed-housing connector beats heat-shrink on durability and repairability. Match the gland to the cable, torque both terminals and housing to spec, and verify continuity before you close it up.
FAQ: Waterproof Splice Connectors
What’s the difference between a waterproof splice connector and a normal butt connector?
A plain crimp butt connector has no moisture barrier. A waterproof splice connector adds a sealed housing or adhesive heat-shrink to block liquid. The enclosed-housing version goes further, sealing the entire joint inside a rugged IP-rated shell — the most durable choice for direct burial and outdoor power immersion.
Can an enclosed splice connector be direct-buried without conduit?
Yes, if it’s IP68 and the datasheet states “direct bury.” Its sealed gland resists soil moisture and groundwater. Note that NEC 300.5 requires at least 6 inches (150 mm) of cover for residential direct burial, and the connector’s IP depth rating must match your actual burial depth.
What wire gauges do most enclosed IP68 splice connectors accept?
Most accept 0.5–6 mm² (about 20–10 AWG), with larger models up to 16 mm² (6 AWG) for high-current outdoor circuits. Always check the datasheet’s minimum and maximum conductor size, since a gland too large or small for the cable prevents a proper IP seal.
Do waterproof splice connectors need regular maintenance?
A correctly installed enclosed IP68 connector needs very little. An annual visual check is wise — look for shell cracks, a shifted gland, or oxidation at the cable entry. Replace the gasket if the connector has been reopened more than three times, and apply fresh dielectric grease at each reconnection, especially for buried or coastal installs.
IP67 or IP68 for a waterproof splice connector — how do I choose?
Use IP67 for above-grade joints that see rain and splash, and IP68 for direct burial, pool, fountain, or any splice that can sit underwater. Because IP68 depth and time are manufacturer-defined, confirm the rated depth on the datasheet matches your burial or immersion depth before relying on it.
