"Aluminum Lugs" is a generic term most commonly applied to UL Listed and CSA certified wire and cable terminals.

Aluminum Lugs are very commonly used in electrical panels and switchgear and typically are mounted using bolts. A bolt through the tang on the Aluminum Lug and through the bus bar is a very efficient way to ensure good mechanical secureness and electrical contact.

The term aluminum lugs also applies to a number of different wire connectors which typically terminate wire to a bus or splice two or more wires together, or allow multiple wires to be terminated at one location. Aluminum lugs are also used for the distribution of electrical power and grounding of electrical equipment.

Multi port lugs are often referred to as "two barrel", "three barrel", "four barrel", and so on. Multi port lugs can be useful for making larger wires manageable by using two or three smaller, more flexible wires to replace one large stiff wire. This is called paralleling wires.

There are electrical codes (NEC) which govern when this is appropriate. For example only wires 1/0 AWG and over may be paralleled and the sizes and types of wire and insulation have to be identical to ensure perfectly balanced load sharing.

Multi wire lugs are those that have been designed and UL approved to hold 2 and sometimes more wires in a single port or wire barrel. This is a very compact way to connect 2 wires in a single barrel lug. Several IHI brand lugs have been approved for multi wire (dual) use for wire gauges from
2x AWG 14
2X AWG 12
2X AWG 10
2X AWG 8
2X AWG 6
2X AWG 4
2x AWG 2

Dual Rated Splicer-Reducer connectors in aluminum are very useful since they can be used to adapt one wire to another in a quick and simple way.

1. Change wire size up or down
2. Change from copper to aluminum wire or reverse
3. Change stranding classes from rigid stranding to FLEX
4. If rated for multiple wires then can split 1 wire to 2 or combine 2 wires into 1.

The P250 does all 4 of these things and is available from LugsDirect.com or MechanicalLugs.com

Mechanical aluminum lugs use wire binding screws to retain the wire in the lug. This makes mechanical aluminum lugs easy to use with no special tools and reusable so that wires and cables may be disconnected and reconnected. Also ideal for customer and field connections where ease of connection is very important.The rotating screw has a natural wiping action which cleans the wire/screw contact zone. Mechanical aluminum lugs are capable of a wide range of wires and cables with no change of connector. This "range taking" property of mechanical aluminum lugs reduces the inventory of lugs needed to cover a wide range of needs and make it easier to standardize the OEM field connectors for various models of differing current and wire size requirements.

Aluminum lugs have a unique ability to be Dual Rated which means that a given lug can take either copper or aluminum wire with no change of lug. This increases the flexibility and choices of wire types and material which may be used with the lug.

Customers increasing chose aluminum wire to reduce wiring costs and yet if copper wire is already installed the same lug will cover both of these cable materials.

UL Listed aluminum lugs are approved for different stranding types such as solid wire, semi rigid stranded, compressed stranded and compacted stranded wire.

In order to use wire and cable in connectors in any UL approved electrical device, a UL486 standard approved lug or wire connector must be used. Whether the lug is approved and marked "Listed for General Use", "Recognized for Use where the Conditions of Acceptability are re-confirmed in the assembly testing, or if an "Unmarked Component of a UL Approved Assembly" - the connector must meet UL486 testing requirements.

UL and the NEC and panel standards UL508 have been changed in recent year to mandate the UL486 testing of all flexible wires and cable since the traditional /UL486 wire connectors were only tested for "rigid stranding" classes ?B and C.

Manufacturers of panels and electrical gear using any wire connector must use only connectors which specifically state in the UL/ CSA files and on product labeling the particular wire class and size of cable.

Generally specific assigned tightening torques are also required so that the compression of the screw on the wire in the geometry of the specific wire hole is maintained as tested.

Most full size Listed lugs are also rated for 90C high temperature wire insulation. Most applications require 75C temperature rated wire insulation however 90C lug ratings can be used at higher currents when 90C wire is used.

The way you can tell what temperature rating an aluminum lug has is to look for the symbols on the lug CU7AL (= AL7CU) or CU9AL (= AL9CU). The AL and CU refer to being approved for aluminum and copper wire. The 7 or 9 is an abbreviation for 75C or 90C wire temperature rating.

90C wire can be used with a 75C rated lug but the current that the wire is allowed to carry must be derated by the NEC table for maximum current for a wire. The 75C column current is chosen in place of the 90C so the current would be the same as if 75C wire had been used. It is often convenient to use 90C wire in a 75C application - the NEC current table just has to be followed in the fuse and circuit breaker capacity of the conductor path.