This article explains the basic concepts of MPO connectors and best practices from a regulatory and technical point of view in Spain.
2. Applicable Regulations in Spain
The main references are:
Royal Decree 346/2011 — ICT Regulations.
Order ITC/1644/2011 — technical development of the ICT Regulations.
UNE-EN 50173 — Generic cabling systems.
UNE-EN 50174 — Cabling installation.
UNE-EN 61754-7 — MPO interface.
ISO/IEC 11801 — structured cabling.
TIA-568.3-D — optical fiber (technical reference).
⚠️ In ICT-regulated installations, the design must comply with these standards even if the connector is not explicitly mentioned.
3. What is an MPO connector?
An MPO (Multi-fiber Push On) connector allows multiple fibers (8, 12, 16, 24, or more) to be terminated on a single interface using an aligned rectangular ferrule.
Advantages:
High density,
smaller footprint,
scalability in data centers,
and rapid implementation.
4. Types of MPO connectors
4.1 By number of fibers
MPO-12 (most common in Spain)
MPO-8 (40G legacy)
MPO-16 (400G)
MPO-24 (trunks)
4.2 By gender
Male (with guide pins)
Female (without pins)
Male must always be connected to female.
4.3 By
UPC polishing (flat)
APC (less common in MPO)
5. Polarity
The polarity must comply with the scheme defined in the ICT or CPD project:
Type A (straight)
Type B (crossed)
Type C (reversed pairs)
It must be documented according to UNE-EN 50174.
6. Best practices according to standard
6.1 Mandatory cleaning and inspection
before connection (UNE-EN 50174).
Use certified MPO cleaners.
Inspection with MPO microscope.
6.2 Handling
Do not touch ferrule or pins.
Keep caps on until connection.
Do not use excessive force.
6.3 Installation
Respect cable bend radii (≥ 10x typical diameter).
Avoid stress on the connector.
Label and document polarity.
6.4 Certification
Measurement of losses according to UNE-EN 50173.
Mandatory documentation in ICT installations.
7. Common Errors
Error
Non-compliance Failure to clean connectors UNE-EN 50174
Failure to document polarity Lack of traceability
Connecting male to male Risk of damage
Exceeding bending radii Loss/breakage
Failure to certify ICT non-compliance
8. Applications in Spain
Data centers
Telecom operators
Large corporate networks
Cloud infrastructure
Building backbones
9. Conclusion
In Spain, MPO connectors must be installed according to UNE standards and the ICT Regulation. Proper cleaning, polarity, handling, and certification are essential to guarantee reliability, safety, and legal compliance.
High density demands a high level of technical expertise.
