In everyday work – whether you are a designer, installer or procurement specialist – electrical cable codes are part of daily routine. They appear in specifications, bills of materials and even printed directly on cable sheaths. Yet behind what may seem like simple sequences of letters and numbers lies a true technical “grammar”. At SADA CAVI, we know how essential it is to choose the right product with no margin for error. For this reason, we want to clarify the Italian designation system CEI UNEL 35011, starting from the basics, exploring some examples, and finally breaking down one of the most widely used codes: the FG16R16 cable.
What is the CEI UNEL 35011 designation system?
The CEI UNEL 35011 system is the Italian standard used to assign a precise and structured identification to power and signalling cables.
Instead of long and complex descriptions, the standard defines a coding system based on sequential blocks of letters and numbers. The concept is simple yet highly effective: by reading the code from left to right, the cable is described from its “core” (the metallic conductor) through to its “skin” (the outer sheath).
This system enables anyone in the industry to immediately understand the construction characteristics of a cable. The main blocks generally follow this order:
- Conductor type and flexibility: indicates the material (copper or aluminium) and whether the conductor is rigid, flexible or solid.
- Insulation: defines the material directly surrounding the conductor (e.g. PVC, rubber, LS0H compounds).
- Shape and assembly: additional letters indicating whether the cable is round, flat or composed of concentric cores.
- Screening or armouring: indicates the presence of mechanical (steel) or electromagnetic (copper) protection.
- Outer sheath: describes the outermost layer, in contact with the environment.
SADA CAVI expert note: The CEI UNEL system is a national standard. If you encounter a cable whose code begins with the letter H (e.g. H1Z2Z2-K for photovoltaic applications), this refers to the European Harmonised system (HD 361), which follows different designation rules.
The structure of cable codes
Below are some examples to better understand how the system is structured into sequential “blocks”:
1. Conductor type and flexibility
This is the starting point of the code. It indicates both the material and flexibility of the conductor:
- A: Aluminium (a cable made of aluminium will begin with A)
- F: flexible stranded conductor (round)
- R: rigid stranded conductor (round)
- U: solid single-wire conductor
Note: If the letter “A” is absent, the conductor is implicitly copper.
2. Insulation
This defines the material directly surrounding the conductor:
- G16: high modulus ethylene-propylene rubber (HEPR) – CPR compliant.
- R / R2: Polyvinyl chloride (PVC).
- S17: PVC with a characteristic temperature of 70°C (CPR).
3. Cable configuration (shape)
This indicates how the cores are arranged within a multicore cable:
- O: cores assembled (with or without fillers) to form a round cable.
- D: parallel cores (flat cable)
- X: helically laid cores (visible lay)
Note: no symbol = single-core cable
4. Screening or armouring (if present)
Additional mechanical or electromagnetic protections:
- H2: copper braid or screen
- A: metallic braid armouring (protection against impact or rodents)
5. Outer sheath
The outer protective layer of the cable:
- R16: PVC compound (CPR)
- M16: thermoplastic compound with low smoke and low acidity (CPR)
A practical example: decoding the FG16R16 cable
To fully understand how the CEI UNEL 35011 standard works, let us apply it to one of the most widely used low-voltage power cables (0.6/1 kV) in modern CPR-compliant installations: the well-known FG16R16.
Let’s break the code down step by step:
- F – Conductor: The first letter identifies the core. “F” indicates a flexible stranded conductor (implicitly copper). If it were aluminium, the code would begin with “A”.
- G16 – Insulation: This block describes the insulation around the conductor. “G16” indicates a special high-modulus ethylene-propylene rubber with low smoke and low acidity, with a characteristic temperature of 90°C.
The number “16” is not a class on its own but part of the compound designation defined within the CPR framework (Construction Products Regulation). - R16 – Outer sheath: The final block defines the outer protective layer. “R16” indicates a PVC-based sheath, also belonging to the family of compounds specifically developed to meet CPR fire performance requirements.
What about FG16OR16?
You may often come across this variant, which includes an “O” in the middle. There is no mystery here: according to the third block rule, the letter O simply indicates that the internal cores are assembled to form a round cable.
Contact SADA CAVI
Understanding the CEI UNEL 35011 system is not just a matter of theory, but a practical tool to work more confidently, avoiding supply errors or non-compliant installations.
At SADA CAVI, our technical team is always available to help you “translate” specification requirements and guide you in selecting the most suitable – and fully compliant – cable for your specific project.
