IEC And GB Insulator Designations Explained

Why There Are Two Codes On Every Row

Our specification tables list a GB class and an IEC class for each column, because a tender in one country may name LXP-160 and a tender in another may name U160BL for the same physical unit. Neither code is a translation of the other. They are two national conventions that happen to describe the same design.

Reading The IEC Form

In a designation like U160BL, the U marks a cap and pin unit, the number is the mechanical failing load in kN, and the letters that follow identify the shed form and variant. A U70BS and a U70BL both carry 70 kN, but the first is spaced at 127 mm and the second at 146 mm.

Reading The GB Form

LXP-160 and LXP1-160 both point at 160 kN classes in the standard profile family. The W in LXWP marks the anti-pollution fog form, so LXWP2-120 is a 120 kN fog unit in the second profile variant. The A in LAXP marks the aerodynamic form.

The Suffixes That Carry Profile Information

P1 and P2 on a fog class distinguish the 255 mm 400 mm creepage profile from the 280 mm 450 mm one. BS and BL on a standard class distinguish the 127 mm and 146 mm spacings. These suffixes are not decoration and changing one changes what arrives on site.

How To Use This When Ordering

Give us the designation exactly as it appears in your specification or on the units you are replacing, including the suffix, together with the coupling size stamped on the cap. Both together identify one column in one of our tables. A class name without a suffix usually leaves two possibilities open.

A Note On Legacy Drawings

Old line drawings sometimes carry designations that have been superseded, or a class written in a form that no current table lists. Send the drawing extract rather than retyping the code. Where we cannot match it to a class we produce, we will say so rather than supply the nearest thing and let site discover the difference.