In air
A push-on cap for an end that stays in air
In air is the only band this part is written for: a moulded PVC shell pushed on by hand over a cut end that will never be splashed, buried or immersed.
In air, and no further
Place the end before you place an order. If it spends its life indoors, inside a panel, in a covered bay or on a drum kept under a roof, a push-on PVC cap is enough. If it will be wetted and dried in cycles, dropped into a trench, or left in a duct that takes water, it is the wrong part, and extra wall thickness does not make it the right one.
The manufacturer's claim for this cap is protection against weathering, moisture and contamination. That is a cover over the end, not a seal into it. There is no adhesive, no mastic and no published ingress rating anywhere on its datasheet, so a fitted PVC cap resists nothing that behaves like a standing head of water. The lined caps sit beside this one in the same catalogue and get ordered by the same engineer on the same afternoon, which is how the wrong one travels to site.
What it is genuinely good at is the half of the job that has nothing to do with water: keeping swarf, dust and paint overspray out of a bore, taking the sharpness off a freshly cut end during handling, and colour-coding a bundle of ends that otherwise look alike. It comes off and goes back on, which is a property rather than a defect — a cap that has to be cut away is a poor choice for an end you intend to open next week.
PVC push-on end cap
A moulded polyvinyl chloride shell pushed by hand over a cut cable, rod or stud end. No heat, no tools, no adhesive, no cure time: the fit is an interference fit on the outside diameter and nothing more.
- Pushes on by hand, so the job needs no torch and no hot-work permit
- Custom lengths and wall thicknesses carry no tooling charge
- Does not crack or split the way low-density polyethylene caps do in service
- More economical than a heat-shrink end cap covering the same diameter
- The only part described on this site whose datasheet carries a flammability result
| Material | Polyvinyl chloride, moulded |
|---|---|
| Exposure band | In air only |
| What it does at the end | Covers it. No lining, no ingress rating |
| Fitting | Push-on, no tools or skill required |
| Dielectric strength | 12 kV/mm minimum |
| Continuous operating temperature | −20 °C to 115 °C |
| Hardness | 65 ± 5 Shore A |
| Flammability | Pass |
| How it is ordered | As a diameter and a length, not from a code table |
Recorded values from the PVC cap datasheet
| Test description | Recorded value | Test method |
|---|---|---|
| Dielectric strength | 12 kV/mm (min.) | ASTM D149 |
| Tensile strength | 12 N/mm² (min.) | ASTM D638 |
| Elongation | 350% (min.) | ASTM D638 |
| Density | 1.23 g/cm³ | ASTM D792 |
| Hardness | 65 ± 5 Shore A | ASTM D2240 |
| Continuous operating | −20 °C to 115 °C | IEC 216 |
| Flammability | Pass | UL 94-V0 |
Each reference in the Test method column is explained once, on what an end-cap datasheet actually proves, and nowhere else on this site.
Push-on PVC against a lined heat-shrink cap
Both of them close a cable end. Only one of them seals it, and the band the end sits in decides which, long before the diameter does.
| Decision | PVC push-on cap | Heat-shrink cap with a lining |
|---|---|---|
| Exposure band it is written for | In air | In air, splash zone, buried or submerged |
| What happens at the end | Covered | Sealed by a hot-melt adhesive lining |
| Published ingress rating | None | IP68 where the lining is specified |
| How it goes on | Pushed on by hand | Gas torch, shrink temperature 125 °C |
| Continuous temperature | −20 °C to 115 °C | −40 °C to +110 °C |
| Taking it off again | Pulls off and goes back on | Cut away, and a fresh cap fitted |
| An odd length or wall thickness | Made to order at no tooling charge | Taken from the published size range |
| Flammability on the datasheet | Pass | Not published |
Why PVC, and why awkward sizes end up in it
Two of the reasons this cap gets specified have nothing to do with how it performs at the end.
- It does not crack or split the way low-density polyethylene caps do. That is the manufacturer's stated reason for the material, and the whole of it — the choice buys durability in handling, not performance at depth.
- Custom lengths and thicknesses carry no tooling charge. That is the practical reason an awkward size ends up in PVC rather than heat-shrink: a one-off length is a moulding decision, not a hunt through a code range for the nearest thing that fits.
- Hardness is quoted at 65 ± 5 Shore A. The heat-shrink cap is quoted at 45 ± 10 Shore D, a different scale, so the two figures will not tell you which cap is tougher.
- No torch means no hot-work permit. Where a flame is prohibited outright that is often the entire decision, worked through on closing an end where a torch is not allowed.
- 12 kV/mm is a property of the material, not a rating for the fitted cap. An energised end is a separate part with its own procedure, covered on the live end cap.
What this cap gets asked
Is a push-on PVC cap watertight?
The cap was on and the end still got wet. What went wrong?
How do I give a size for one?
Does the same cap go on a pole crown or a dock pile top?
Can I push one over a crimped terminal in a panel?
Where to read next
The order below runs downward, the way the bands run everywhere on this site.
- A cut cable end, from a dry store to a flooded ductThe hub the seven cable-side caps hang from
- Insulcap heat-shrink cable end caps, sealed for burialThe same cut end, one band deeper
- Closing an end where a torch is not allowedWhere the permit decides, not the part
- What the tests on an end-cap datasheet actually proveEvery method in the table above, explained once
- Six ways a closed end opens againGrouped by band, because the failures differ with depth
- Four size charts, and how to read a codeThe code ranges that exist, and the one that does not
A diameter, a length and a band
Three lines settle it: the outside diameter over the end, how much of it you want covered, and confirmation that the end stays in air for its whole working life. If the third line is not certain, say so, and the reply will quote the lined cap instead.