Short answer: Somfy requires its SDN Low-voltage Motor Power and Data Cable between a PowerConnect panel and every RS485 DC motor. Order 9020127, the plenum-rated version for any ceiling that moves return air. Use 9020126, the non-plenum version, everywhere else. Both carry the same conductors and the same 240 ft limit per motor port.
Cable is the cheapest line on the shade schedule and the fastest way to fail a ceiling inspection. A crew pulls the non-plenum reel through a return-air ceiling, the inspector reads the jacket print, and the cable comes out. That is a re-pull on labor you already paid for. The fix costs nothing at submittal time.
Free spec package
SDN Plenum Cabling Drawing Set: 9020127 / 9020126 with PowerConnect
- SMD-01 general notes and system limits schedule with a source for every number
- SMD-02 PowerConnect elevation (published dims) and SDN cable conductor detail
- SMD-03 plenum riser, Weidmuller 5-position pinout and wiring schedule
- SMD-04 three-part guide spec language, BOM and a ceiling inspection checklist
Two part numbers, one build
Somfy publishes one spec sheet for both cables. Each reel holds 1,000 ft. Inside the jacket you get a 14 AWG twisted power pair, a 22 AWG twisted and shielded data triad, and a 24 AWG drain. The sheet calls it a five-conductor cable: two for 24V DC power and three for SDN RS485 data. The drain rides along under the foil.
Somfy rates the cable for 300 V maximum and 8 A at 77°F. The data triad meets the TIA/EIA-485 standard, which is the RS485 physical layer SDN motors talk on. The construction is identical across both reels. Only the jacket listing changes.
That matters for estimating. Your terminations, your pinout and your run limits stay the same whichever reel the space calls for. One wiring detail covers the whole job.
CL3P or CL3R: read the ceiling first
Somfy's spec sheet lists the cable as NEC rated CL3R or CL3P at 75°C, in accordance with NEC Article 725. CL3R is the riser listing. CL3P is the plenum listing. Somfy 9020127 is the plenum-rated reel. Somfy 9020126 is the non-plenum reel.
The NEC substitution order runs one way. A plenum cable may go anywhere a riser cable may go. A riser cable may not enter a space used for environmental air. Mechanical drawings tell you which ceilings carry return air. Pull them before you count reels.
Our rule: if one segment of a home run crosses a return-air ceiling, the whole run is 9020127. Splicing jackets mid-run adds a junction and saves nothing. The AHJ has the final word on every space classification.
The panel can live in the plenum too
The cable is half the plenum question. The other half is the box it lands on. Somfy's spec sheet for the SDN PowerConnect Surface-Mount Panel 1871026 lists it as plenum-rated to UL 2043 and indoor use only. UL 2043 is the fire test for equipment installed in air-handling spaces. The enclosure is powder-coated steel, the cover measures 12 in by 12 in, and the box mounts on the wall or in the wall between studs.
Each panel adds 10 isolated motor ports and two isolated device ports to an SDN bus segment. Somfy's guide spec lists the input as 120 Vac at 7.2 A and the output as 24 Vdc fused at 2 A per motor. Ten motors per panel sets your panel count before you size a single circuit.
Rack jobs use the SDN PowerConnect Rack-Mount Panel 1871027. Our rule: keep the rack-mount panel in the equipment rack and let 9020127 make the trip through the ceiling. The surface-mount panel is the one Somfy documents for the plenum.
Run length and port math
Somfy publishes 240 ft of power and data wiring per isolated motor port, panel to motor, using the SDN Low-voltage Motor Cable. Each motor gets its own home run. Measure the route through the ceiling. Ceiling routing around ducts and beams adds feet fast.
The Somfy cable spec sheet also covers the SDN PoE Gateway layout. Keep the switch-to-gateway leg at 300 ft or less on Category 5e. Keep the total cable from the gateway to all of its motors at 240 ft or less.
Both motors on the PowerConnect compatibility list take this cable: the Sonesse 30 RS485 24V DC 1241144 and the Sonesse ULTRA 50 RS485 24V DC 1134022. Somfy lists both on the 9020126 and 9020127 product pages as well.
SDN cable numbers to put on the drawings
- 9020127 plenum, 9020126 non-plenum: same build, 1,000 ft reels
- 14 AWG power pair, 22 AWG shielded data triad, 24 AWG drain
- 300 V maximum, 8 A at 77°F, NEC CL3R or CL3P at 75°C
- 240 ft maximum per PowerConnect motor port
- 10 motor ports and 2 device ports per PowerConnect panel
- PoE Gateway: 300 ft Cat 5e to the switch, 240 ft total to its motors
Terminate it the way Somfy drew it
The pinout never changes between the two reels. Pin 1 is 24V DC positive on red. Pin 2 is 24V DC negative on black. Pin 3 is SDN RS485 positive on orange-white. Pin 4 is SDN RS485 negative on orange. Pin 5 is SDN RS485 ground on brown. The drain is silver.
Somfy's motor port connector is the SDN Weidmuller 5-position field-installable connector, in male and female versions. Label both ends. The guide spec calls for wire labeling and for separation of power and low-voltage data wiring in the pre-installation meeting, so put both on the submittal.
Write the cable into the spec
Somfy guide spec 12 25 09 already holds the hooks. Section 1.3 asks for low-voltage wiring responsibilities, separation of power and data wiring, and wire labeling. Section 1.4 asks shop drawings to show wiring between components, gauge and wire limitations. Section 2.4 states the 240 ft panel-to-motor limit using the Somfy SDN Low-Voltage Motor Cable.
Section 2.4 also gives you two responsibility paragraphs: low-voltage wiring by the roller shade contractor, or by Division 26. Pick one. Leaving both in the spec is how cable ends up on nobody's bid. Part 3 points the installer to NFPA 70, NECA 1 and NECA 130.
Our rule: add one bracketed line under the cable paragraph: [9020127 plenum-rated in all air-handling spaces; 9020126 permitted elsewhere]. One sentence closes the substitution door.
Line-voltage motors play by a different rule
This guide covers the 24V SDN cable. AC motors ship with a cord instead. Somfy moved its 500 and 600 series motors to a 10 ft SJTW cord as standard, and cites UL 325 clause 13.7.3 for SJTW or heavier cord and clause 13.3.4 for a cord length of 1 ft to 10 ft. The guide spec sends flexible cords to NFPA 70 Article 400.
Two motor families on one job means two cable conversations. Keep the SDN cable on the low-voltage schedule and the cords on the electrical coordination list with Division 26.
Take the spec package to your submittal
SDN Plenum Cabling Drawing Set: 9020127 / 9020126 with PowerConnect
- SMD-01 general notes and system limits schedule with a source for every number
- SMD-02 PowerConnect elevation (published dims) and SDN cable conductor detail
- SMD-03 plenum riser, Weidmuller 5-position pinout and wiring schedule
- SMD-04 three-part guide spec language, BOM and a ceiling inspection checklist
FAQ
Can I use 9020127 plenum cable in a wall or riser?
Yes. A plenum-listed cable may go anywhere a riser-listed cable may go. Our rule: on a mixed job, one 9020127 reel on the truck removes the wrong-reel mistake.
Is the Somfy SDN cable shielded?
The 22 AWG data triad is twisted and shielded with a 24 AWG drain. The 14 AWG power pair is twisted and unshielded, per Somfy's spec sheet.
How far can I run SDN cable from a PowerConnect panel?
Somfy publishes 240 ft of power and data wiring per isolated motor port, from the panel to the motor, using the SDN Low-voltage Motor Cable.
Can the PowerConnect panel go above the ceiling?
Somfy's spec sheet lists the PowerConnect Surface-Mount Panel 1871026 as plenum-rated to UL 2043 and indoor use only. Confirm access and location with the AHJ.
Sources: Somfy product pages for 9020126, 9020127 and 1871026 (somfysystems.com); Somfy SDN Low-voltage Motor Power and Data Cable spec sheet and SDN PowerConnect Surface-Mount Panel spec sheet (Somfy documents, read from OEM copies); Somfy guide specification 12 25 09 (ARCAT); Somfy, "Somfy Motor Cabling Change Helps With UL Listing" (Dec 8, 2020).
Ryan Towns writes the Somfy Integrator Guides for ShadeMotorsDirect, an authorized Somfy distributor. Questions on a spec or a retrofit: 859-414-6872 or colin@shademotorsdirect.com, 8:00 AM - 7:30 PM ET.
