Four letters, four layers
The letters run from the inside out: insulation, bedding, braid or armour, outer sheath. A two-letter code such as RU names only the insulation and the sheath.
Reference tool — not inspection
Read the cable before it goes in an RFQ.
Marine cable
Letters, screens, size.
Type the designation. Below the examples, the designation of an offered cable can be checked against it: cores and cross-section, insulation, the other layers, the screen and the voltage. The drawing and the RFQ line update with every change.
Examples:
Replacement check
On the designations alone: the class approval, the cable route and the glands decide.
All 130 engineering tools
Ship and offshore cables to NEK 606 are named in letters, one per layer: insulation, bedding, braid or armour, outer sheath; the screens, the voltage and the size follow. Type the print from the sheath or the drum, and the reader decodes each letter, draws the cable stripped back and writes the RFQ line.
Only letters that a second maker’s cable construction confirms are decoded; the others are marked as not decoded. The cable datasheet and the class approval still decide.
How a designation is read
Layers from the inside out.
B or R
B is mica tape under the insulation: the circuit keeps working in a fire (IEC 60331). R cables are flame retardant (IEC 60332-3-22) but not fire resistant.
Screens and figures
(i) and (c) are the screens; 0.6/1 (1.2) kV or 150/250 (300) V is the voltage, Uo/U (Um); 4x2x0.75 is four pairs of 0.75 mm².
| Letter | Layer | Meaning |
|---|---|---|
| R | Insulation | ethylene propylene rubber (EPR), halogen-free on NEK 606 cables |
| B | Insulation | mica tape under halogen-free EPR: the fire resistant version |
| T | Insulation | cross-linked polyethylene (XLPE) |
| P | Insulation | PVC |
| F | Bedding | bedding, tape or inner covering over the cabled cores |
| X | Bedding | none |
| O | Braid or armour | copper wire braid, tinned on NEK 606 cables |
| C | Braid or armour | galvanised steel wire braid |
| X | Braid or armour | none |
| U | Outer sheath | halogen-free thermosetting compound, SHF2 on NEK 606 cables |
| P | Outer sheath | PVC |
The full code has more letters for each position; the reader decodes only those a second maker’s cable construction confirms. X means the layer is not there.
Sources
Letter code and NEK 606 cable types: Draka Norsk Kabel (Prysmian), offshore cables guide, "Code designation for cables". Each letter checked against a cable construction on Nexans Norway’s product pages: RFOU, BFOU, BFOU(i), the RFCU and BFCU options, TFXP and PFXP; individual screens also against Caledonian’s BFOU(i) page, the collective screen against Prysmian’s RFOU(c) and BFOU(c) datasheets. Core counts with G: Nexans and Onninen listings of 3G1,5 cables. Voltage notation Uo/U (Um): Nexans; Um 1.2 kV for 0.6/1 kV cables: IEC 60502-1.
Before you send the cable
Questions about cables in an RFQ
What does BFOU mean?
Four letters for four layers in the NEK 606 code: B, mica tape under halogen-free EPR insulation, the fire resistant version; F, the bedding or inner covering; O, a copper wire braid, tinned on NEK 606 cables; U, a halogen-free thermosetting outer sheath, SHF2.
What is the difference between RFOU and BFOU?
The insulation. RFOU has halogen-free EPR and is flame retardant (IEC 60332-3-22, Cat. A); BFOU adds mica tape under the EPR, so the circuit keeps working in a fire (IEC 60331). Where a circuit has to keep working in a fire, the request names BFOU.
What do (i) and (c) mean?
The screens of an instrumentation cable: (i) gives each pair or triple its own screen, a metal-backed polyester tape with a tinned copper drain wire; (c) puts one collective screen over all of them.
What should the request include?
The designation as printed (letters, screens, suffix), the number of cores or pairs and the cross-section, the voltage, the NEK 606 type number if printed, the length and drum lengths, and the class approval needed. A photograph of the print on the sheath settles the rest.
Cable read?
Send the line with the photograph.
A decoded designation is a cross-check, not proof. Attach a photograph of the print on the sheath, and Vessel Core checks it against the cable datasheet before an offer goes back.
Buyer tools
