Product · BUSCAP · GBC1–GBC18

What a BUSCAP does at a live bar end

Eighteen moulded PVC sizes, GBC1 for a 15 × 5 mm bar up to GBC18 for 200 × 12 mm. It covers the cut end of a live bar and comes off in minutes when that end has to be reached.

Five ways to insulate a busbar Send a bar section

BUSCAP busbar end cap, GBC series

BUSCAP is a flexible PVC cap that covers the end of a live busbar. Eighteen consecutive sizes run from GBC1, for a 15 × 5 mm bar, to GBC18, for 200 × 12 mm, and the cap reaches 20, 30, 50 or 70 mm back along the bar depending on the code. It is tested to ANSI C37.20.2 for medium-voltage switchgear application to 36 kV, and it installs, removes or replaces in a few minutes.

Covers a square-cut bar end with no tape, no wrap and no heat gun
Comes off for a torque check or a thermographic survey and goes back on afterwards
Sized on the bar section, so the code is read off a chart rather than quoted
UV and ozone resistant, so the same part suits an outdoor kiosk
Custom design and colours, including phase identification at the end of a run

Part codes	GBC1 to GBC18 — eighteen consecutive sizes
Bar section covered	15 × 5 mm to 200 × 12 mm
Cap length	20, 30, 50 or 70 mm by code
Material	Flexible PVC, formulated for high-voltage electrical application
Switchgear standard	ANSI C37.20.2, medium-voltage application to 36 kV
Fitting	Mechanical, not heat-recovered; re-usable; off and on in minutes
Environment	Resistant to UV and ozone; indoor or outdoor
Options	Custom design and colours

ANSI C37.20.2ASTM D149ASTM D638ASTM D792ASTM D2240IEC 216UL 94-V0

Manufacturer datasheet (PDF)

Heat barrier is the query; dielectric barrier is the part

A cap over a bar end is a dielectric and mechanical barrier. It does not slow heat leaving the copper, and nothing published about BUSCAP says it will — the one temperature on its datasheet, −20 °C to 115 °C, is a limit on the cap, not a protection for the bar. The phrase is typed into a search box far more often than it appears on a datasheet, and it stands in for one of two other things.

The first is a barrier against the heat and pressure of a fault. Containment of an internal arcing fault is a property of how an enclosure is built, vented and type-tested, not of any cover fitted to a bar, and no BUSCAP document claims it. The second is a cover recovered with a torch at 125 °C. A shrunk cover is destroyed on removal; this one is mechanical, which is why the same cap goes back on after an inspection.

Read the phrase as an insulating barrier at the end of the bar and the part matches. Read it as thermal protection for the copper and the line item is wrong before the panel is cut.

GBC selection chart — bar section to code

Gala code	Bar section A × W (mm)	Cap length L (mm)
GBC1	15 × 5	20
GBC2	20 × 5	20
GBC3	25 × 5	20
GBC4	30 × 10	30
GBC5	40 × 10	30
GBC6	50 × 6	30
GBC7	50 × 10	30
GBC8	60 × 10	30
GBC9	65 × 8	30
GBC10	75 × 6	50
GBC11	80 × 10	50
GBC12	100 × 6	50
GBC13	100 × 10	50
GBC14	100 × 24	50
GBC15	120 × 10	50
GBC16	125 × 10	50
GBC17	150 × 6	70
GBC18	200 × 12	70

A is bar width, W is bar thickness, L is how far the cap reaches back along the bar. Eighteen discrete sections, not a continuous range — a 90 × 10 mm bar has no row.

Published properties, and the method each was measured by

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 temperature	−20 °C to 115 °C	IEC 216
Flammability	Pass	UL 94-V0

Measured on the PVC compound, not on a fitted cap. Five of these seven rows match the BUSBOOT PVC shroud exactly, which is what the same compound looks like — but the dielectric row does not: the cap is published at 12 kV/mm against the shroud's 16 kV/mm, so neither table may be read onto the other part. Every method above is decoded on the standards page.

Four phrases used interchangeably at a bar end, and the differences that matter

Heat barrier: As the term is used in busbar searches, an insulating barrier over live metal. Not a thermal barrier: a cap adds no useful resistance to heat leaving the bar, and no published figure rates it against a temperature rise.
Dielectric barrier: What the cap is. PVC at 12 kV/mm minimum standing between a live copper edge and everything else in the enclosure, tested for switchgear duty to ANSI C37.20.2.
Arc barrier: A partition qualified for an internal arcing fault — established by type-testing an assembled enclosure. A push-on cap is not one, and no source claims it as one.
Heat-shrink cover: A part recovered onto the conductor at 125 °C with a torch or hot-air gun. The BUSTUBE sleeve and the bus sheet work that way; the cap does not, which is why it comes off intact.
GBC code: The size designation. Eighteen consecutive codes name a bar section from 15 × 5 mm to 200 × 12 mm — a bar dimension, never a voltage class.

The four things a cap at a bar end addresses

All four are initiating events rather than faults in progress, and that boundary is the whole of what a cap buys.

Accidental contact. The cut end is the surface a hand, a sleeve or a test lead meets before any other part of the run.
Dust and debris bridging. A horizontal edge collects settled deposit, and conductive dust turns an air gap into a partial path.
Field concentration at the edge. A sheared or sawn end has a small radius, so stress peaks exactly where the copper stops and the air begins.
Rodent and dropped-tool ingress. A covered end removes the shortest path to earth in a cable basement or an outdoor kiosk.

The chart sizes a cap to a bar, not to a voltage

Every GBC code names a bar section in millimetres. None names a voltage. The 36 kV figure is one ANSI C37.20.2 switchgear-application statement covering the series, so the code comes from the bar and the voltage is a question about the panel. Do not work backwards from a shroud chart either: the shroud is specified by system voltage, from 1.25 mm of wall at 3.3 kV to 4.50 mm at 38 kV, and a cap is specified by section. The manufacturer also claims a significant reduction in air clearance for BUSCAP, but every clearance figure on this site was measured on the sleeve — that argument lives here.

Cap, shroud, sleeve or sheet — chosen by geometry

Voltage sets the wall. Geometry sets which part it is.

What is being covered	The part	How it is sized
The cut end of a bar, live	BUSCAP end cap	Bar section, GBC1 at 15 × 5 mm to GBC18 at 200 × 12 mm
A bolted joint, tee or elbow	BUSBOOT shroud	System voltage — PVC wall 1.25 mm at 3.3 kV to 4.50 mm at 38 kV
The straight run between supports	BUSTUBE heat-shrink sleeve	Bar width plus breadth, read against the sleeve size chart
A flat face or an inter-phase gap	Bus sheet or barrier board	Cut to an area, not moulded to a profile

Bar-end questions

Does a busbar cap stop arcing?

Not once an arc has struck. What a cap removes is a set of initiating events: a spanner dropped across the end, a rodent bridging edge to earth, conductive dust settling on the cut face. That is prevention at the bar. Containment is a property of the assembled enclosure and is proven by type test, not by a cover.

Is BUSCAP a heat barrier?

It is a dielectric barrier — PVC at 12 kV/mm minimum, tested to ANSI C37.20.2 for switchgear application to 36 kV. It is not thermal insulation, and its published range of −20 °C to 115 °C bounds the cap rather than the bar. If a drawing genuinely calls for a thermal barrier, that requirement belongs to the busbar design.

Which GBC code fits my bar?

Read the section off the chart above: a 100 × 10 mm bar is GBC13, 50 × 10 mm is GBC7, 40 × 10 mm is GBC5. The chart holds eighteen discrete sections, so a bar falling between two rows — 90 × 10 mm, for instance — has no code, and that is an enquiry rather than a rounding decision. Sizing from a shroud chart gives the wrong part, because a shroud is chosen by voltage.

Can it be taken off for a thermographic survey or a torque check?

Yes, and that is the operational case for a moulded cap over a taped end. It refits in minutes, so an outage that includes an infrared check or a re-torque does not consume the part. Removing any cover from a bar is still work on the bar, and belongs inside the permit.

Are custom colours and non-standard shapes available?

Custom design and colours are offered. Phase identification at the end of a run is the usual reason to ask; a bar profile outside the eighteen chart sections is the other. This site publishes no price, lead time or minimum quantity for either — those come from the manufacturer.

Where this page hands off

Every part named here is manufactured by Gala Thermo Shrink Pvt. Ltd. at Palghar, Maharashtra. The chart and the property table above are the manufacturer's own published figures.

Send the bar section and the voltage

A cap does not extinguish an arc, does not raise a panel's fault rating, and does not substitute for clearance the design already needed. It keeps hands, dust, tools and rodents off a square-cut copper edge, and comes away again when that edge has to be reached. Read the code off the chart, then send the bar width, the thickness, the system voltage and the number of ends.

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