DLO Cable Lugs: Terminating Fine-Stranded DLO

The Short Answer

Use compression lugs identified for fine-stranded (flexible) conductors, sized for the exact DLO size, and crimp them with the tool and die the lug maker specifies. Do not use a standard mechanical (set-screw) lug unless it is marked for fine-stranded conductors, and never trim strands to make the cable fit.

Why DLO Is Different: Strand Count

DLO strand counts are typical and vary a little by manufacturer; the cable's print or spec sheet has the exact figure. Class B counts are the usual concentric stranding for building wire such as THHN and XHHW-2. Ampacity for each DLO size is on the DLO ampacity chart.

A 4/0 building wire has 19 strands; a 4/0 DLO has more than 500. That is what makes DLO flexible, and it changes three things at the lug:

• The conductor is larger in diameter than building wire of the same size, so it may not enter a barrel made for Class B wire.
• Fine strands spread and escape under a set screw instead of clamping as a solid bundle.
• The sizes above 4/0 do not match building wire. DLO comes in 262.6, 313, 373 and 444 MCM (and larger), not 250, 300, 350 and 500 kcmil.

What the Code Says

NEC 110.14 requires connectors and terminals used on conductors more finely stranded than Class B and Class C to be identified for the specific conductor class. DLO is Class I, so the lug's marking, carton or instructions must list fine-stranded or flexible conductors, and the conductor size you are terminating. A lug that only lists standard stranding is not acceptable, however well the cable seems to fit.

Choosing the Lug

• Type: a flex-rated compression lug, ideally with a chamfered (flared) barrel entry so the strands feed in without catching.
• Size: from the lug maker's table for flexible conductors, for the exact DLO size. Do not round to the nearest building-wire size.
• Material: tin-plated copper is the usual match for DLO's tinned conductors.
• Stud hole and pad: from the equipment. Note the stud diameter, and whether the terminal needs one hole or two.
• Tool and die: the ones the lug maker lists for that lug. The listing covers the lug, die and conductor together.

Making the Termination

1. Strip carefully to the barrel depth. Nicked strands on a fine-strand conductor add up fast.
2. Keep every strand. Do not fold back or trim strands to force a fit. If the conductor will not enter the barrel, the lug is wrong.
3. Seat the conductor fully. Use the inspection hole, if the lug has one, to confirm the strands reach the end of the barrel.
4. Crimp with the specified die, the number of times and in the order the lug maker shows.
5. Seal it where it will get wet. Heat-shrink tubing over the barrel keeps moisture out of the strands.
6. Bolt it to the equipment maker's torque value with the hardware the equipment calls for.

Get the termination right and DLO connections stay cool for decades. Get it wrong and the lug is the failure point, not the cable.

Common Mistakes

• Using a set-screw lug from the building-wire bin.
• Choosing a 250 kcmil lug for 262.6 MCM DLO because the numbers are close.
• Trimming or folding strands to get the cable into the barrel.
• Crimping with whatever die is in the tool.
• Leaving the barrel open to water on outdoor or washdown equipment.

Ordering DLO for a Job With Terminations

We cut DLO cable to the lengths you need. When you work out footage, allow for the strip length at each end and for the bend into the terminal. Full construction data for every size is on the DLO spec sheet (PDF), and our DLO cable guide covers ratings and where DLO is used.

Frequently Asked Questions