Questions we actually get asked

Cross-linked polyolefin, expanded in the factory, holding that shape until heat is put on it. Then it goes back. A wraparound version is split along its length, so it closes from the side instead of threading over an end. The shrink stops when it meets the jacket, and a hot-melt lining is squeezed into every irregularity as it arrests. The wall is mechanical. The lining is the seal.

The part does not need the shutdown. The manufacturer's wrap-around sleeve sheet says it in one line: shut down of system not required for repair. Nothing is cut, and the sleeve closes from the side. Your permit is a separate question and no datasheet answers it. There is no live-working rating, no approach distance and no operator qualification on the GWS or GMRS charts. Where this manufacturer does mean live, it marks the part. The Insulcap-Live outer cap carries a live flash symbol. These sleeves carry none.

It is published per code, in three steps: 25 mm on the smaller GMRS sizes, 50 mm through the middle, 75 mm on the largest. Each is a minimum measured around the circumference, not a target. Your code carries its own figure on the size chart. Trimming works the wrong way round here. Cutting a sleeve to suit a narrower cable takes the lap first, and the fit still looks right after it has gone.

The GMRS bands overlap rather than meet, so a diameter in the forties sits on two rows. Take the smaller code, provided its supplied diameter still passes the largest obstruction in the repair length. A cable near the top of a band reaches the published minimum overlap with nothing in hand. If both candidates came off the GWS chart, check which version you read. The web page and the printed sheet give different cable ranges against the same codes, and both are reproduced on the size chart.

No. PVC insulating tape has no memory to recover. Heat softens it, the tension it was wound at opens the spiral, and what reads as shrinkage is the roll relaxing. The one wrap here that does recover is coded GMT-2L, shrink temperature 125 °C. The method is IEC 216. The rest of that swap is on heat shrink tape vs electrical tape.

Under compression, yes. Loose, no. Butyl seals by being squeezed between two faces that stay pressed together afterwards. What the Mastic Tape sheet never prints, for any grade, is an ingress protection rating. The IP68 figure quoted elsewhere on this site belongs to the hot-melt lining inside a recovered sleeve, not to a strip of mastic left in the open. The mechanism is on what mastic tape is.

Hot enough to recover, never hot enough to scorch. The instruction on the manufacturer's Polecap sheet is specific: propane ahead of butane, the flame adjusted soft and blue with a yellow tip, never pencil-like, and kept moving continuously so nothing scorches. The Insulcap-Live sheet adds the outer 75 to 100 mm of the flame, which that sheet gives as 3 to 4 inches, in a rapid brushing motion. Recovery begins above 125 °C and a flame runs far hotter, so technique decides this and not a setting. Let the part cool before any mechanical strain goes on it. The sequence is on installation.

It drags the ends back off the land they were meant to seal onto. Longitudinal change is the row that measures it, and minus 10 percent maximum is what the manufacturer prints on its post-tensioning coupler and busbar tube sheets. The method is ASTM D2671. The GWS and GMRS charts carry no such row, so that limit cannot be read onto a repair sleeve. Leave a seating length beyond the damage at each end, and stop once the wall is down on the substrate.

It depends which sheet you are holding, and the wraparound sheets are silent. The joints and terminations catalogue lists no shelf life limitation at or below 50 °C. The non-shrinkable EPR insulation tape publishes five years minimum, held at +10 °C to +30 °C. Nothing equivalent appears on the wrap-around sleeve, the repair sleeve, the mastic or the three-layer pipeline sleeve. Get the storage condition confirmed against your own code rather than borrowed from a neighbouring product.

Three things, and none of them is a judgement call. Touch safety: the dielectric figures on these sheets are strength per millimetre of wall, measured on a test piece to ASTM D149 or ASTM D2671, which is a material property and not a voltage class, a touch-safe rating or a reason to move an approach distance. Structure: a pole sleeve stops the mechanism and returns nothing, because the Pole Protection Sleeve sheet puts the highest stress in the outer sapwood at the ground line and that is the layer decay and termites take first. Pressure: no sheet in this range publishes a pressure rating, a burst figure or a containment claim. The three-layer pipeline sleeve resists liquid pressure from outside on a buried coating. It is not a repair for a pipe that is losing product.