Which joint kit series fits the cable in front of you
Insulation, core count, voltage class. Those three answers pick the series; the conductor size only picks which code inside it.
Three questions, asked in this order
What is the cable insulated with? How many cores? What system voltage does it run at? Those three select the series. The conductor size then selects the code inside that series, and nothing else on the sheet gets a vote.
Order matters, because a later answer does not survive a wrong earlier one. An 11 kV paper-insulated lead-covered run does not take a three-core XLPE kit one class up. It takes a GPS. Core count is not a size band, and voltage class is not something you round.
Two things are worth settling before you enquire even though neither changes the series. Whether the cable is armoured, and where the joint will end up — a pit, a flooded duct, direct burial. Both change what you have to say when you ask. And if the cable is ending rather than carrying on, stop here: that is a termination and it comes off a different chart, which the manufacturer's terminations index holds.
The selector
Read across from the cable you have. The series is the answer here; the code is the next question, and it lives on the size chart.
| Cable in front of you | Cores | System voltage | Series | Codes on the chart |
|---|---|---|---|---|
| Extruded solid dielectric, XLPE or PVC, armoured or unarmoured | 1, 2, 3, 3½ or 4 | 1.1 kV | GXLT/GPLT | GXLT-1 to GXLT-6 |
| The same cable one step up | 1, 2, 3, 3½ or 4 | 3.3 kV | GXLT/GPLT | GXLT-11 to GXLT-16 |
| Paper-insulated, armoured or unarmoured | 1, 2, 3, 3½ or 4 | 1.1 or 3.3 kV | GXLT/GPLT | One chart, shared with the extruded rows |
| XLPE, EPR or PVC, shielded, armoured or unarmoured | 3 | 12 kV, 15–24 kV or 36 kV | GXS/1236 | GXS-11 to GXS-15, GXS-21 to GXS-25, GXS-31 to GXS-34 |
| XLPE, EPR or PVC, shielded, armoured or unarmoured | 1 | 12 kV, 15–24 kV or 36 kV | GXSS/1236 | GXSS-11 to GXSS-15, GXSS-21 to GXSS-25, GXSS-31 to GXSS-35 |
| Paper-insulated lead-covered | 3 | 11 kV, Umax 12 kV | GPS/1112 | GPS-11 to GPS-15 |
| Screened paper-insulated lead-covered | 3 | 24 and 36 kV series, up to 33 kV | GPS/2436 | GPS-21 to GPS-24, GPS-31 to GPS-34 |
| Paper one side, XLPE the other | 3 | up to 12 kV | GTJ/1112 | GTJ-11 to GTJ-15, then GTJ-17 — no GTJ-16 is printed |
| Paper one side, XLPE the other | 3 | 24 and 36 kV | GTJ/2436 | GTJ-21 to GTJ-25, GTJ-31 to GTJ-34 |
| Submersible cable | not published | not published | GXLTS | No chart in any catalogue held here |
Splice, splicing kit, splicer — all the same shelf
If you arrived searching for a cable splicing kit, nothing needs translating. The manufacturer's own page for the GXLT/GPLT series is headed as both a cable joint and a cable splicing kit, so the two words already sit on one product: that is the page.
The map runs both ways and it is short. Splice is joint. Splicing kit is jointing kit. Splicer is jointer. A splice kit size is a kit code. Medium voltage cable splicing is MV jointing, and an MV cable splice kit is one of the ten rows in the table above.
One thing does not carry across. American splice kits get quoted against AWG and kcmil. These charts are not, and that is the next section.
Voltage class, as the charts actually label it
| Class on the chart | System voltages the sheet names (Uo/U) | AC withstand, 1 minute | DC withstand | Lightning impulse, crest |
|---|---|---|---|---|
| 12 kV | 6.6/6.6 kV, 6.35/11 kV | 35 kV | 48 kV | 75 kV |
| 15–24 kV | 8.7/15 kV, 11/11 kV, 12.7/22 kV | 50 kV | 96 kV | 125 kV |
| 36 kV | 19/33 kV | 75 kV | 144 kV | 170 kV |
| 1.1 and 3.3 kV | Umax 1.1 kV and Umax 3.3 kV | 3.5 kV and 6 kV, immersed, 5 min | 15 kV and 21 kV dry, 5 min | 8 kV and 12 kV |
Uo/U pairs and withstand figures copied from the GXS/1236 and GXSS/1236 electrical performance tables; the same three classes head the GPS/2436 and GTJ/2436 sheets. The bottom row is tested to a different regime — joint immersed in water rather than dry — so it does not sit on the same scale as the three above it.
Two sheets disagree on how long the DC test runs
The GXSS/1236, GPS and GTJ charts all head the DC column 30 minutes. The GXS/1236 chart prints the identical 48, 96 and 144 kV figures under 1 minute. Voltages agree across every series; only the duration does not, and one of the two is a typesetting error that cannot be resolved from the published sheets. If that duration is going into a tender clause, get it confirmed in writing before it is quoted.
Square millimetres, and only square millimetres
Every ordering chart in this range is written in sq mm. GXSS-13 covers 150 to 300 sq mm at 12 kV. GXS-15 covers 400 to 500. GTJ-11 covers 3x16–35. No AWG column and no kcmil column appears anywhere in the joints catalogue.
A code is a band, and the bands shift with the voltage class. GXS-11 opens at 16 sq mm at 12 kV, GXS-21 opens at 25 at 15–24 kV, GXS-31 opens at 35 at 36 kV. So a 95 sq mm conductor sits in GXS-12, GXS-22 or GXS-32 according only to the system it runs on. Read the class first, then the row.
Convert from kcmil by area if you have to, but treat what comes out as the opening line of an enquiry rather than as the answer. Area is not diameter, and it is the diameter every sleeve in the kit has to close onto.
The codes carry one more caution. The series is written GXLT/GPLT throughout and the ordering table prints GXLT codes only — no GPLT code appears in it. That table also runs to GXLT-6 and GXLT-16 with a 4x300–400 sq mm row, while the manufacturer's web page for the same series stops at GXLT-5 and GXLT-15. Anything above 4x185–240 sq mm, get the code confirmed before it is ordered.
No source for that
Three gaps, printed rather than written round. AWG and kcmil — no crosswalk is published; every band in the joints range is sq mm. North American class labels — the sheets name 6.6/6.6, 6.35/11, 8.7/15, 11/11, 12.7/22 and 19/33 kV, and never print a 5, 15, 25 or 35 kV class, so any mapping onto those is yours rather than the manufacturer's. GXLTS — the submersible series is named in the range list and carries no chart in any catalogue held here: no codes, no conductor sizes, nothing to schedule against.
When the cable sits between two series
Four boundaries account for most of the wrong kits opened on site.
Three cores, or one
GXS and GXSS run the same three voltage classes and read like one family with two size ranges. They are not. Core count is the entire difference and it is the thing ordered wrong. A GXSS bill of material carries no wraparound joint case, because a single-core joint has no crutch to protect. You find that out at the box, on site, with the cable already cut back.
The conductor falls in a gap
Bands do not always butt together. At 15–24 kV the GXS chart runs 25–50, 70–95, 120–150, 185–240 and 300–400 sq mm, so 60, 100, 160 and 260 sq mm sit in no row at all. At 12 kV the opposite happens and 120 sq mm appears in both GXS-12 and GXS-13. A chart of ranges is not a rounding rule. Neither the gaps nor the overlap are yours to settle.
Paper one side, XLPE the other
No straight-through kit spans two constructions. That is a GTJ. The two parts on its manifest that exist only because of the transition are the barrier-type inline connector and the heat-shrink oil barrier sleeve, both there because of the oil the paper cable carries — the sheets name those parts and leave the reason to the name. Three oil barrier sleeves in a GTJ/2436 kit, one per core.
The system sits on a class edge
15 kV and 22 kV both land inside the 15–24 kV class, and 33 kV is the 36 kV class, printed on the sheet as 19/33 kV. Quote the Uo/U pair from your cable schedule alongside the class, because the class name on its own does not say which of the three listed systems you are actually on.
Where a kit from this range is the wrong answer
Every sleeve and tubing in these kits recovers under applied heat, and there are between four and nine distinct ones on a manifest. On a job where hot work is not permitted — a purged pit, a fuel installation, a live substation under a no-naked-flame permit — none of GXLT, GXS, GXSS, GPS or GTJ is the right call, and no figure on this page gets you round it. That is a cold-shrink or a cast-resin joint, and neither appears as a joint kit anywhere in the manufacturer's published range held here — the cold-shrink items listed are tubing and breakouts in EPDM rubber, not a straight-through joint.
There is a stores argument running the other way and it is worth stating without inflating it. One heat-shrink code covers a band — GXSS-13 takes anything from 150 to 300 sq mm — so a short list of part numbers covers a long run of cable sizes. How narrow a cold-shrink body's application range runs by comparison is a question for a cold-shrink chart, and no cold-shrink joint datasheet is held here to answer it. The mechanism comparison sits on shrink-tube.com, published by Gala Thermo Shrink, the same manufacturer that makes these kits: heat shrink or cold shrink.
The rest of the boundary is simpler. A conducting breakout is a line item inside these kits rather than a family you select from, busbar work is bolted and belongs to a different trade entirely, and plain tubing is bought by recovered diameter. All three are handled where they touch a joint, on the parts list, and none of them comes off the table on this page.
Give the cable, and the code comes back
Five lines, and the part number is not one of them. Insulation type. Core count. Conductor size in sq mm. System voltage as a Uo/U pair. Armoured or unarmoured. Add where the joint will live if that is a duct, a pit or under water. Kit Sheet publishes the reference and nothing else — no price, no lead time, no stock position.