The Raychem RDSS (Rayflate Duct Sealing System) from TE Connectivity is an inflatable duct seal for power cable ducts. A flexible plastic laminate bladder with high-temperature sealant strips on both sides wraps around the cable or cables. Inflated to about 45 psi (3 bar), it presses the sealant against the duct wall and the cable jacket to make a watertight seal, and a self-sealing gel valve closes the fill hole when the filling tube comes out. TE lists it for plastic, steel and concrete ducts, in dry or wet conditions.
| Item | What TE lists |
|---|---|
| Seal | Flexible laminate bladder with high-temperature sealant strips on both sides |
| Inflation | 3.0 +/- 0.2 bar (about 45 psi), with a hand inflator that has a gauge and pressure limiter |
| Fill hole | Self-sealing gel valve prevents pressure loss once the filling tube is removed |
| Installation condition | Dry or wet, including a duct with water still flowing through it |
| Duct systems | Concrete, plastic or steel |
| Duct shape | Independent of duct ovality |
| Cables | Empty ducts, or ducts with one or more cables, with different cable diameters allowed in the same duct |
| Test report | EDR-5253 |
| Drawing | EPD-202-312007-01 (TE says to use it for all design work) |
TE's RDSS catalog (EPP-0569) describes these tests. The detailed test report is available from TE on request.
| Test | Result TE lists |
|---|---|
| Water and gas tightness | Water tight and gas tight at up to 0.3 bar (a 3 m water column) at room temperature, including with the cables under vibration, bending, torsion, pull and push |
| Chemical and bacterial resistance | Passed |
| Load cycling | Tested with a conductor temperature of 90 degrees C, following VDE 0278 Part 1, for use on high current cables |
| Empty and multi-cable ducts | Water and gas tight at 0.3 bar |
| Service life | Calculations show the seals still hold 0.3 bar of a 3 m water column after 30 years, based on a typical daily utility load cycle at 25 degrees C ambient and diffusion measurements at elevated temperatures |
These are the admissible cable diameters, in mm, that TE lists for each kit by duct inside diameter. For a bundle of cables, use the diameter of the bundle. A dash means the kit does not cover that duct size.
| Duct ID (mm) | RDSS-45 | RDSS-60 | RDSS-75 | RDSS-100 | RDSS-125 | RDSS-150 |
|---|---|---|---|---|---|---|
| 32.5 | 0 - 14 | - | - | - | - | - |
| 35 | 0 - 18 | - | - | - | - | - |
| 40 | 0 - 27 | - | - | - | - | - |
| 45 | 0 - 32 | 0 - 18 | - | - | - | - |
| 50 | - | 0 - 30 | - | - | - | - |
| 55 | - | 0 - 38 | 0 - 28 | - | - | - |
| 60 | - | 0 - 45 | 0 - 30 | - | - | - |
| 65 | - | - | 0 - 40 | - | - | - |
| 70 | - | - | 0 - 46 | - | - | - |
| 75 | - | - | 0 - 56 | 0 - 45 | - | - |
| 80 | - | - | - | 0 - 52 | - | - |
| 85 | - | - | - | 0 - 60 | - | - |
| 90 | - | - | - | 0 - 66 | - | - |
| 95 | - | - | - | 0 - 74 | - | - |
| 100 | - | - | - | 0 - 80 | 0 - 65 | - |
| 105 | - | - | - | 0 - 85 | 0 - 75 | - |
| 110 | - | - | - | 0 - 90 | 0 - 83 | - |
| 115 | - | - | - | 55 - 95* | 0 - 91 | - |
| 120 | - | - | - | 60 - 100* | 0 - 95 | - |
| 125 | - | - | - | - | 0 - 103 | 60 - 100 |
| 130 | - | - | - | - | 70 - 110* | 60 - 107 |
| 135 | - | - | - | - | 75 - 115* | 60 - 112 |
| 140 | - | - | - | - | 80 - 120* | 60 - 118 |
| 145 | - | - | - | - | 85 - 125* | 60 - 123 |
| 150 | - | - | - | - | 90 - 130* | 60 - 129 |
| 155 | - | - | - | - | - | 60 - 134* |
| 160 | - | - | - | - | - | 60 - 139* |
| 165 | - | - | - | - | - | 105 - 145* |
| 170 | - | - | - | - | - | 110 - 150* |
| 175 | - | - | - | - | - | 115 - 155* |
| 180 | - | - | - | - | - | 120 - 160* |
An asterisk means an RDSS-CLIP must be used even with only two cables. For duct sizes over 180 mm, ask TE. Each RDSS element can seal an empty duct (except the RDSS-150, where TE offers empty-duct sealing on request) or a duct with up to two cables. The RDSS-100 at 115 and 120 mm, the RDSS-125 at 130 to 150 mm, and the RDSS-150 are for ducts with cable only. TE's catalog pairs the RDSS-AD-210 adapter with the RDSS-125 and RDSS-150.
The RDSS-100 cut sheet gives the maximum cable bundle diameter by duct size and cable count. TE's catalog says to subtract 5 mm from the chart value for each clip used. Measure the bundle with a diameter tape, or ask TE.
| Duct ID | 0 to 2 cables | 3 to 4 cables (1 clip) | 5 to 7 cables (2 clips) |
|---|---|---|---|
| 3.25 in. (83 mm) | 2.2 in. (56 mm) | 2.0 in. (50 mm) | 1.8 in. (46 mm) |
| 3.50 in. (89 mm) | 2.6 in. (66 mm) | 2.4 in. (61 mm) | 2.2 in. (56 mm) |
| 3.75 in. (95 mm) | 2.9 in. (74 mm) | 2.7 in. (69 mm) | 2.5 in. (64 mm) |
| 4.00 in. (100 mm) | 3.2 in. (80 mm) | 3.0 in. (75 mm) | 2.8 in. (70 mm) |
| 4.25 in. (108 mm) | 3.5 in. (89 mm) | 3.3 in. (85 mm) | 3.1 in. (79 mm) |
| 4.50 in. (114 mm) | 3.5 in. (89 mm) | 3.3 in. (85 mm) | 3.1 in. (79 mm) |
When a duct holds three or more cables, an RDSS-CLIP (a sealing star) goes between the cables to close the gaps. TE describes the clip's high-temperature sealant as filling all the spaces between the cables, and lists it for medium voltage cable including unjacketed concentric neutral.
| Cables in the duct | Clips needed |
|---|---|
| 1 to 2 | None (except where the chart is marked *) |
| 3 to 4 | 1 clip |
| 5 to 7 | 2 clips |
| More than 7 | Contact TE |
One clip seals up to four cables, and each additional three cables need one more clip. Each kit has a matching clip.
| RDSS kit | Matching clip |
|---|---|
| RDSS-45 | RDSS-CLIP-45 |
| RDSS-60 and RDSS-75 | RDSS-CLIP-75 |
| RDSS-100 | RDSS-CLIP-100 |
| RDSS-125 | RDSS-CLIP-125 |
| RDSS-150 | RDSS-CLIP-150 |
Clips come 5 per box and are ordered separately from the seal elements. The clip sealant, S-1278, is sold separately.
TE says the whole installation takes only a few minutes, even in tight spaces, with no mixing or filling of liquids.
| Step | What to do |
|---|---|
| 1 | Apply the lubricant to the sealant strips of the RDSS bladder, or to the clip if you use one. TE's lubricant is a soap solution applied with a sponge head. |
| 2 | For three or more cables, position the clip between the cables |
| 3 | Wrap the seal around the cable and push it into the duct |
| 4 | Inflate the bladder with the hand inflator to 3 bar. The gauge and pressure limiter keep it at 3.0 +/- 0.2 bar. |
| 5 | Remove the filling tube. The gel valve closes automatically so the bladder keeps its pressure. |
TE says a seal can be removed by releasing the gas, without damaging the ducts, so cables can be replaced or added later and the duct sealed again. Because the seal adapts itself to the duct, it also seals deformed ducts, and it can be installed in a duct that still has water flowing through it. See the installation instructions (EPP-0570) for the full procedure.
| Part number | What it is | Package |
|---|---|---|
| RDSS-IT-16 | Inflation tool with on/off switch, gauge and automatic pressure limiting, uses CO2 cylinders. Supplied in a carrying case with instructions. | 1 per box |
| E7512-0160 | 16 g CO2 cylinders for the RDSS-IT-16. TE's catalog says one cylinder is enough for about 5 RDSS-100 seals, and the cut sheet says about 4. | 10 per box |
| RDSS-IG-SR-AS | Inflation tool for customer-supplied nitrogen or compressed air, with gauge, auto shutoff and hose connections | 1 per box |
| E7512-0220, E7512-0240, E7512-0260 | Spare tube snap assembly, pressure gauge assembly and delivery pipe for the RDSS-IT-16 | 1 per box each |
| S-1278-3x61x7620 | RDSS sealant roll | 25 ft roll |
| RDSS-AT/AP-150 | Adapter for the RDSS-150 when the cable bundle is under 2.4 in. (60 mm) | 1 per box |
| RDSS-AD-210 | Adapter used with the RDSS-125 and RDSS-150. The cut sheet lists it for 6.5 to 8.0 in. (165 to 210 mm) ducts. | 4 per box |
| E4540-1250 | RDSS-LUBE installation lubricant | 25 per box |
TE's catalog packs RDSS seal elements 10 to a carton with one bottle of lubricant and the installation instructions. The RDSS-100 is also sold in packs of 3. Duct sizes are from TE's catalog.
| Kit | Duct inside diameter | Pack |
|---|---|---|
| RDSS-45 (S10) | 32.5 to 45 mm (about 1.28 to 1.77 in.) | 10 wraps |
| RDSS-60 (S10) | 45 to 60 mm (about 1.77 to 2.36 in.) | 10 wraps |
| RDSS-75 (S10) | 55 to 75 mm (about 2.17 to 2.95 in.) | 10 wraps |
| RDSS-100 (S10) | 75 to 120 mm (about 2.95 to 4.72 in.) | 10 wraps |
| RDSS-100 (S3) | 75 to 120 mm (about 2.95 to 4.72 in.) | 3 wraps, 1 lubricant dispenser, installation instructions; sold in multiples of 3 |
| RDSS-125 (S10) | 100 to 150 mm (about 3.94 to 5.91 in.) | 10 wraps |
| RDSS-150 (S10) | 125 to 180 mm (about 4.92 to 7.09 in.), cable only | 10 wraps |
RDSS is a mechanical seal and the Polywater foams are chemical seals, so they suit different jobs. See the ZipSeal vs FST vs AFT guide for the foam side.
| Raychem RDSS | Polywater foam (ZipSeal, FST, AFT) | |
|---|---|---|
| How it seals | Inflated bladder presses sealant strips against the duct and cables | Two-part urethane foam expands and hardens into a closed-cell seal |
| Tested water head | 0.3 bar (3 m, about 10 ft) per TE's catalog | ZipSeal 30 ft, FST 22 ft continuous, AFT 11 ft on PVC |
| Sizing | A kit per duct size, within a maximum cable diameter | FST for 2 to 8 in. conduits, AFT for 3/4 to 10 in., ZipSeal for small conduits and innerducts |
| Several cables in a duct | RDSS-CLIPs close the gaps between cables | Foam fills around the cables; separate them first |
| Mixing | None | Two-part foam mixes in the nozzle |
| Tools | Hand inflator, with CO2 cylinders or nitrogen or compressed air | Dispensing tool or aerosol can |
| Removal | Release the gas and the seal comes out without damaging the duct | Pierce and break the foam bond, then pull the plug |
| Conditions | Dry or wet installation, in concrete, plastic or steel ducts | Foam does not cure below 40 degrees F (4 degrees C) per Polywater's FAQ |
Raychem's Rayflate Duct Sealing System, an inflatable bladder with sealant strips that seals around cables in a duct.
To 3.0 +/- 0.2 bar (about 45 psi), with the RDSS-IT-16 tool and CO2 cylinders or the RDSS-IG-SR-AS tool and nitrogen or compressed air.
Yes. TE lists installation in dry or wet conditions, and says the seal works even with water flowing through the duct.
Concrete, plastic or steel. TE says it does not depend on duct ovality, so it also seals deformed ducts.
TE tested water and gas tightness at up to 0.3 bar, with the cables under vibration, bending, torsion, pull and push.
TE's calculations show the seals still hold 0.3 bar of a 3 m water column after 30 years.
Use RDSS-CLIPs between the cables. One clip seals up to four cables, with one more clip for every three additional cables. For more than seven cables, contact TE.
Do not exceed the maximum cable bundle diameter for the duct, or the bladder may not inflate properly. Subtract 5 mm from the chart value for each clip used, and move up to the next kit or ask TE if the bundle is too large.
Yes. Release the gas and the seal comes out without damaging the duct, so cables can be changed and the duct sealed again.
TE's catalog says about 5 RDSS-100 seals per 16 g cylinder, and the cut sheet says about 4.
Yes. The RDSS-150 covers ducts up to 180 mm (about 7.1 in.), and TE pairs the RDSS-AD-210 adapter with the RDSS-125 and RDSS-150. For larger ducts, ask TE.
To order an RDSS kit, clips or inflation tools, contact Powertech Associates at info@powertech-upsc.com or (860) 678-8772 with the duct size and number of cables. You can also search all RDSS products in the store.
Last updated: November 2026.
