How to Choose Rubber Flexible Cable or Welding Cable

Are rubber flexible cable and welding cable interchangeable?

No. Portable tools, cranes, pumps, construction equipment and welding machines each impose different movement, and the cable name does not tell you which standard or voltage rating applies. The two cables below are a useful starting point for comparison, but neither should be substituted for the other without checking its standard.

• H07RN-F is a 450/750 V flexible cable with EPR insulation, a polychloroprene sheath and a class 5 conductor (EN 50525-2-21).
• H01N2-D is an arc-welding cable rated up to 100 V with a class 6 copper conductor (EN 50525-2-81).

Use the rubber flexible cable and welding cable product pages to compare constructions, then confirm the final choice against the datasheet of the exact product.

How do you describe the movement the cable will see?

State whether the cable flexes occasionally or continuously, reels, twists or drags. A cable that bends during installation is not necessarily designed for continuous reeling or torsion, so the motion should be described before the conductor class and sheath are chosen.

• State intermittent or continuous flexing.
• Give the bend frequency, the bending radius, the travel speed and any reeling or twisting.
• Describe the travel surface and any contact with edges or debris.

With these details, the supplier can check the conductor class and sheath against the actual motion, instead of against a general "flexible" label.

How do you size a welding lead?

Welding current is often intermittent, so the duty cycle matters as much as the current itself. Conductor size depends on current, duty cycle, one-way lead length, allowable voltage drop and ambient temperature. Current flows out through one lead and back through the other, so the length that counts is the full loop, which is about twice the one-way length.

Conductor resistance is the starting point for the voltage-drop check. IEC 60228 gives maximum DC resistance at 20 °C for plain copper classes 1 and 2; for example, 1.15 Ω/km for 16 mm² and 0.193 Ω/km for 95 mm². Classes 5 and 6 have their own limits, so take the value for the class you are buying from the standard or the datasheet.

1. Confirm the welding current and the duty cycle from the welding equipment data.
2. Agree the one-way lead length, including any extension.
3. Set the allowable voltage drop and the ambient temperature for the site.
4. Select the conductor size from the supplier's sizing data rather than a rule of thumb.

Connections matter as much as the conductor. Keep terminations tight and protected from damage, and check for heating at connectors during use.

Which standard and sheath suit the site?

Rubber-family sheaths can be formulated for weather, oil and mechanical resistance, but performance varies between compounds. State the contaminants, temperature range and outdoor exposure rather than asking only for "rubber cable". Account for oil, water, heat and abrasion when you compare sheaths.

The table summarizes the two cables and shows what is still missing when a cable is ordered only as "rubber cable".

Ratings are taken from the cable standards and product data named in the references. Confirm them on the datasheet of the exact product before ordering.

Temperature limits need the same care. H01N2-D datasheets list −40 to +85 °C for fixed installation, which does not by itself describe performance under flexing. H07RN-F datasheets differ on maximum conductor temperature, so take that value from the datasheet of the exact product.

How should you handle and inspect the cable in service?

Observe the minimum bending radius and the pulling limits. These depend on the cable construction, so take them from the manufacturer's datasheet for the exact product rather than from a general rule. Inspect the cable regularly, especially where it is dragged or passes over edges.

• Look for cuts, crushed areas and exposed conductor.
• Check connectors and terminations for overheating, especially on welding leads.
• Inspect dragged cable for cuts and crushing.

Remove damaged portable cable from service according to the site procedure. Welding and mobile-equipment circuits require application-specific sizing and safety review.

Frequently asked questions