In air
A crimped terminal in a panel is an open end in air
Dry, indoors, at hand height, behind a door. The first band on this site's exposure scale, and the only one an unheated push-on moulding closes on its own.
One part here, four that are not
This page describes the moulded PVC cap that closes a crimped wire-end terminal or a cable lug inside a panel. Busbar end caps and busbar sleeving belong to busbarsleeves.com. Shrouding over live switchgear metal belongs to busbar-boot.com. Two unrelated objects also answer to insulation cap in search: the end-cap insulation inside an electric motor, and the capped termination of pipe lagging. Neither is covered below.
What in-air changes
An end at this depth is not asking to be sealed. It is asking to be covered, so that a finger or a dropped spanner cannot reach live metal and so that it is still pliable in year twelve. Every other band on this site is chosen against water. This one is chosen against contact, which is why the part slips on cold rather than recovering under a flame.
The body is moulded in flexible PVC. Dielectric strength is published at 16 kV/mm minimum, tensile strength at 12 N/mm² minimum, elongation at 350% minimum, and the continuous band runs -20 °C to 115 °C. The same moulding has been tested for switchgear application up to 36 kV.
115 °C is the figure to read twice: a cap on the crimp is heated through the metal rather than by the air around it, so it sees the terminal's temperature and not the panel's.
Two body styles, and a third option
The shape follows the terminal, not the conductor.
Over a crimped wire-end terminal
A closed body over a ring or pin terminal and the bared conductor behind the crimp barrel. This style carries the 16 kV/mm minimum and the switchgear test to 36 kV, so it is the one to quote inside medium-voltage equipment. The manufacturer's page.
Over a straight or flat-type terminal
Open-ended rather than closed. Recesses in the tab shoulders hold the terminal seated against vibration, and a sleeve carries past the crimp to keep dust out of the cable end. Self-extinguishing. Published separately: the fit differs, the compound does not.
Moulded to your drawing
A cap that nearly fits is a cap that comes off in a lorry. Custom sizes, shapes and colours are moulded to order, with no tooling charge published on PVC.
Colour belongs on the drawing, not in the stores
Colour here is moulded in, not applied afterwards. It is fixed at the order and cannot be changed by the fitter. The cap is often the last thing onto a terminal and the first thing seen on opening the door, so it carries phase or circuit identification whether or not that was planned.
Name a colour against each terminal in the panel schedule. Leave it out and the board is built from whatever is in the bin.
Crimped wire-end terminal cap
| Property | Value | Test method |
|---|---|---|
| Dielectric strength | 16 kV/mm (min.) | ASTM D149 |
| Tensile strength | 12 N/mm² (min.) | ASTM D638 |
| Elongation | 350% (min.) | ASTM D638 |
| Continuous operating temperature | -20 °C to 115 °C | IEC 216 |
| Switchgear application | Up to 36 kV | ANSI C37.20.2 |
Material data for the moulding. None of it is a system voltage rating for the terminal underneath.
Straight and flat-type terminal cover
| Property | Value | Test method |
|---|---|---|
| Dielectric strength | 12 kV/mm (min.) | ASTM D149 |
| Tensile strength | 12 N/mm² (min.) | ASTM D638 |
| Elongation | 350% (min.) | ASTM D638 |
| Continuous operating temperature | -20 °C to 115 °C | IEC 216 |
| Flammability | Self-extinguishing | ASTM D876 |
Dielectric strength and the flammability entry are the only published differences between the two styles.
What this part will not do
Stated because the datasheet does not state them.
- It covers, it does not seal. No ingress rating is published for either style. The sleeve on the flat-terminal body keeps dust out of the cable end — a claim about particles, not about water reaching the crimp. Where water is the problem the barrier is the gland.
- 36 kV is a test on the moulding, not a rating for the joint. It does not say the terminal beneath is insulated to 36 kV, and it replaces no creepage calculation.
- Nothing recovers. No torch, no shrink ratio, no recovered diameter, so the recovered-diameter tables do not apply here.
- Fit is to the terminal body, not the conductor size. A cross-sectional area alone will not pick between the two styles.
Questions this part gets asked
Does it need heat to fit?
Can we have our own phase colours?
What does 16 kV/mm actually tell me?
Will it survive outdoors?
Where to go next
Asking for a moulding to order
A dimensioned sketch of the terminal, the colour against each position, the quantity, and the destination. Send those four and a drawing comes back instead of a question.