Breakout size chart

Insulcore-LV, 2 to 7 core

Sixty-five codes, from the March 2025 issue of the manufacturer's low-voltage selection chart. Across all 69 low-voltage rows that sheet differs from the manufacturer's product page in exactly two places. It prints LV3GBB-2154 A where the page prints LV3GBB-2145 A, and it gives LV5GBB-0832 A as 100 → 33 mm where the page gives 85 → 37 mm. Both differences are set out at cable breakouts.

Insulcore-LV, the four codes with two leg sizes

This second chart exists because these four crutches do not have legs of one size. It adds a second leg diameter, a second leg length and a second leg wall thickness, so a cable whose cores differ can be sized on a single row. LV2GBB-61820 is the clearest case: one leg is published at 44 → 18 mm and the other at 25 → 6 mm. Counted with the 65 above, these four make the 69.

GCEB cold shrink, 2 and 4 core

Two 2-core sizes and two 4-core sizes, and nothing between or beyond them. No 3, 5, 6 or 7-core cold-shrink breakout appears on this chart, so a 3-core crutch that cannot take a flame is not served here. The operating temperature is published as two different figures on the manufacturer's two pages for this part, and both are printed at cold shrink breakouts.

Sizing a row on both ends at once

This is a reading of the published charts, not a procedure the manufacturer publishes. Where a datasheet or a packed installation instruction says otherwise, that document governs.

1. The body diameter, over the sheath

   The first figure is the cable's outside diameter where the body will sit, just back from the crutch. It is taken on the cable in front of you rather than off the drawing, because armour and bedding move it.

2. One core diameter, past the crutch

   The second is the outside diameter of a single core just past the crutch, over its own insulation. Where the cores are not all one size, both the largest and the smallest matter, and the second chart exists for that case.

3. The supplied figures are the clearance

   Ds and ds are minimums. They are what the part has to pass over on its way into position, so both measured diameters sit under them. On a made-off cable the widest thing it travels across is not always the crutch.

4. The recovered figures are the grip

   Df and df are maximums, taken in free recovery with nothing inside the part. Both measured diameters have to sit above them. Otherwise the part reaches its own limit before it touches the cable, and nothing is gripped.

5. LV3GBB-1330, worked through

   Body 80 → 30 mm, legs 36 → 13 mm. That row suits a 3-core cable under 80 mm over the sheath and over 30 mm at the crutch, whose cores each measure under 36 mm and over 13 mm. A cable at 62 mm with 22 mm cores sits inside both bands. The same cable with 12 mm cores does not, because the legs would reach free recovery before they touched.

6. Length is checked last, and loosely

   Ls and ls say how far the part reaches along the cable and along each core. Where a gland, a lug or a clamp sits close behind the crutch, that figure decides whether the part fits the space rather than the cable.