Perma-Seal™ Step-Down Butt Splices

Waterproof Splices for Secure Connections


What’s special about butt splice connectors?

  • Allowquick and easy splicing of 2 different sized wires, or joining of 2 wires into 1
  • Specially formulated NiAc material shrinks at 40% faster rate than standard polyolefin heat shrink tubing for quicker application
  • Thick walled shrink tubing is abrasion and cut resistant to protect your wiring connections (UL 94V-2)
  • RoHS compliant
  • Click for More Features
RoHS Compliant


Part #DescriptionWire Gauge ColorPack Qty Price
WW-38058Perma-Seal™ Step Down Butt Splice Connectors22-19 AWG to 16-14 AWGBlue with Red Stripe100
Manufacturer Direct
WW-38059Perma-Seal™ Step Down Butt Splice Connectors16-14 AWG to 12-10 AWGYellow with Blue Stripe100
Manufacturer Direct
  • Ideal for use in harsh environments
  • Weather and chemical resistant material to protect wiring
  • See through insulation allows you to inspect crimping
  • Abrasion and cut resistant material
  • 3:1 shrink ratio
  • Low shrink temperature: 90° C
  • Solvent resistant


These heat sealed step-down butt connectors provide additional protection against the elements. When connecting two different sized wires or joining two wires to one, this is the perfect solution. The smaller end of the connector is color coded for easier identification and quick installation.


Barrel Type Closed
Insulation NiAc(TM)
Temperature Range - Operating -55° to +125° C
Shrink Temperature 90° C
Wire Insulation Diameter 5.84mm (0.230") max
Voltage - Maximum 600V


Internal Diameter

Part # WW-38058 WW-38059
Size 16-14 AWG Side 12-10 AWG Side 22-19 AWG Side 16-14 AWG Side
Before Shrinking 0.305 0.305 0.230 0.230
After Shrinking 0.098 0.138 0.076 0.089

* Polyolefin based hot melt adhesive

Limiting Oxygen Index (LOI)
The ratio of how much oxygen - as compared to other gases - needs to be present in the air surrounding a particular material in order for that material to burn. The fact that Earth's normal atmospheric air contains around 21% oxygen is used a reference point when materials are classified into burn categories that are based on Limiting Oxygen Index. Substances that are combustible in air containing less than 21% oxygen are considered flammable, while those that burn in the range of anything greater than 21% but less than 28% are typically labeled "slow burning". Any material with an LOI that exceeds 28% is classified as self-extinguishing.

In the table below, you'll find a list of polymers commonly found in our heat shrink tubing and braided sleeving products, along with their LOIs and the burn categories each falls into.

ECTFE (Ethylene chlorotrifluoroethylene) Halar 64% Self Extinguishing
Nomex N/A 28% Slow Burning
Nylon 6:6 N/A Ranges fron 24-29% Slow Burning to Self Extinguishing
PET (Polyethylene Terephthalate) Mylar (film), Dacron (fiber) Ranges from 21-34% Slow Burning to Self Extinguishing
Polyethylene (PE) N/A 17% Flammable
Polypropylene (PP) polythene (in the UK) 17% Flammable
Polytetrafluoroethylene (PTFE) Teflon 95% Self Extinguishing
Polyvinyl Chloride (PVC) N/A Ranges from 45-49% Self Extinguishing



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