NSi Industries 6-Port Aluminum...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$248.76
NSi Industries 6-Port Aluminum Dual-Rated Transformer Lug

NSi Industries 6-Port Aluminum Dual-Rated Transformer Lug

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Model: STL250-6

In Stock (leaves warehouse same day if ordered before 3pm ET)

$248.76
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NSi Industries 6-Port Aluminum Dual-Rated Transformer Lug

The NSi Industries 6-Port Aluminum Dual-Rated Transformer Lug is a heavy-duty transformer connector built for demanding electrical tap and splice applications. Machined from 6061-T6 aluminum alloy and electro-tin plated for low contact resistance, this connector accepts a wire range of 250 MCM - 6 AWG and is dual-rated for copper or aluminum conductors. Two NEMA 1/2" mounting holes simplify attachment, and the connector carries a 600V voltage rating with a 90 C maximum operating temperature for reliable performance in transformer and panelboard wiring.

Key Features

  • Wire Range: Accepts 250 MCM - 6 AWG conductors for versatile transformer tap and splice connections.
  • Durable Construction: Made from 6061-T6 aluminum alloy for strength and corrosion resistance in mechanical connector applications.
  • Dual-Rated Conductors: Suitable for both copper and aluminum conductor terminations, adding installation flexibility.
  • Easy Mounting: Two NEMA 1/2" holes allow for quick, secure attachment to bus bars, transformers, and equipment.
  • Voltage Rating: Rated 600V for use in transformer, panelboard, and tap connection applications.
  • Finish: Electro-tin plated finish provides low contact resistance and long-term connector performance.
  • Temperature Rating: Rated for a maximum operating temperature of 90 C.

Technical Specifications

  • INNER WIDTH: 6.1
  • WARRANTY: 1 Year
  • Product Series: STL
  • Field Application: Tap
  • Number of Conductors/Circuits/Terminals: 6

Typical Applications

  • Transformer Terminal Connections
  • Electrical Tap and Splice Applications
  • Commercial and Industrial Electrical Installations
  • Panelboard and Switchgear Wiring
  • Aluminum-to-Copper and Copper-to-Copper Conductor Terminations
  • Renovation and New Construction Electrical Work

Why NSi Industries?

NSi Industries builds this transformer lug from 6061-T6 aluminum alloy with an electro-tin plated finish, delivering the durability and low contact resistance professional electricians rely on for transformer and tap connections. With a dual-rated design that accepts both copper and aluminum conductors across a 250 MCM - 6 AWG wire range, this connector supports code-compliant, reliable performance for commercial and industrial electrical installations.

Manufacturer Resources

Product Specs

Wire Size:
250 MCM - 6 AWG
Sub Division:
Electrical-E H2
Division:
Electrical H1
Max Temperature:
90 C
Warranty:
1 Year
Series:
STL
Hole Spacing:
1.75 IN
Field Application:
Tap
Voltage Rating:
600V
Hex Wrench Size:
16-May IN
Number of Conductors/Circuits/Terminals:
6
Country Of Origin:
United States
Conductor Type:
Copper, Aluminum
Product Material:
6061T-6 Aluminum Alloy
Product Finish:
Tin Plated
Product Type:
Mechanical Lug
Department:
Electrical
Product Group:
Wire Connectors & Terminals
Product Subgroup:
Lugs & Terminals

NSi STL250-6 – Frequently Asked Questions

1) What wire sizes will the NSi STL250-6 transformer lug accept, and can I mix copper and aluminum in it?
The STL250-6 takes conductors from 250 MCM down to 6 AWG in each of its six ports, and it is dual rated for both copper and aluminum. That means you can land aluminum feeders and copper taps in the same lug, which is the usual reason electricians reach for a dual-rated mechanical connector on a transformer terminal.
2) How does the NSi STL250-6 lug mount, and what is the hole spacing?
It mounts with two NEMA 1/2 inch holes on 1.75 inch centers, so it bolts straight to a bus bar, transformer pad, or equipment landing pad drilled to that spacing. Check your pad centers before ordering, because a pad drilled to a different NEMA spacing will not line up.
3) Is the NSi STL250-6 rated for 600V panelboard and switchgear work?
Rated 600V, with a 90 C maximum operating temperature. That covers normal 208/240/480V commercial and industrial distribution, transformer terminations, and panelboard or switchgear wiring. For conductors with insulation rated above 90 C, the lug caps the connection at 90 C.
4) Why choose a 6-port transformer lug instead of individual single-conductor lugs?
A six-port block like the STL250-6 lets you tap or splice up to six conductors off one bolted landing, which saves pad space and bolt holes inside a crowded transformer cabinet or panelboard. Single lugs make sense when you only need one or two terminations, or when each conductor has to land on its own separate pad. The STL250-6 is built for tap applications specifically.
5) Will an aluminum-bodied lug corrode where I land copper conductors?
The body is 6061-T6 aluminum alloy with an electro-tin plating, and the tin plate is what makes copper contact acceptable and keeps contact resistance low. Tin plating on aluminum is the standard construction for dual-rated mechanical connectors used in Al-to-Cu terminations. Follow normal practice and apply the joint compound your installation calls for on aluminum conductors.
6) Can I use the STL250-6 for a service entrance tap on 4/0 aluminum?
Yes. 4/0 aluminum sits comfortably inside the 250 MCM to 6 AWG range, and the lug is rated for aluminum conductors. The same lug will take smaller branch conductors down to 6 AWG in the remaining ports, so you can feed several taps of mixed sizes off one block.
7) Is the NSi STL250-6 transformer lug made in the USA?
Country of origin is the United States. That matters on public and institutional jobs carrying domestic-sourcing requirements, so it is worth noting on the submittal.
8) What is the exact part number and model for the NSi 6-port aluminum transformer lug?
Manufacturer part number STL250-6, from NSi Industries' STL series of mechanical transformer lugs. The 250 refers to the top of the wire range, 250 MCM, and the 6 to the six conductor ports.
How fast can I get the NSi STL250-6 delivered?
Most orders ship the same day from our distribution partners, with quick delivery throughout the continental U.S. Need it urgently? Contact Us for expedited shipping options.
Can I return it if it doesn’t work for me?
Yes—ZenSupply offers a hassle-free return policy. If the product isn’t the right fit, reach out to our support team for a return authorization or setup a return by following our return instructions.
Does the NSi STL250-6 come with a warranty?
Absolutely. The NSi STL250-6 is backed by a manufacturer’s warranty. For full warranty terms, check the product documentation or Contact Us.
How do I get technical support or installation help for the NSi STL250-6?
You can call, text, or email our expert support team for fast answers. We’re here to help with product selection, installation tips, and troubleshooting. Contact Us
Why buy the NSi STL250-6 from ZenSupply?
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