Labelling Requirements for TOP SECRET Conduits
TOP SECRET conduits must have labels every 5 metres, marked 'TS RUN', and be at least 2.5 cm by 1 cm in size.
Plain language
This control is about making sure that the infrastructure used to carry highly sensitive information is clearly labelled. If these labels are not present, someone might accidentally damage the conduits or connect unauthorised devices, leading to leaks of top-secret information which could significantly harm national security or an organisation's operations.
Framework
ASD Information Security Manual (ISM)
Control effect
Preventative
Classifications
TS
ISM last updated
Feb 2021
Control Stack last updated
19 Mar 2026
E8 maturity levels
N/A
Section
Cabling infrastructureTopic
Labelling ConduitsOfficial control statement
Labels for TOP SECRET conduits are a minimum size of 2.5 cm x 1 cm, attached at five-metre intervals and marked as 'TS RUN'.
Why it matters
Missing 2.5 cm x 1 cm 'TS RUN' labels at 5 m intervals increases the chance TOP SECRET conduits are misidentified or mishandled, risking compromise of TOP SECRET data.
Operational notes
Inspect TOP SECRET conduits to confirm 2.5 cm x 1 cm 'TS RUN' labels are present every five metres, legible, securely attached, and not covered or removed.
Implementation tips
- The facilities manager should ensure that all conduits designated for carrying top-secret communications are labelled correctly. Arrange for labels to be ordered through a trusted security supplier, ensuring the labels meet the required size and content specifications.
- The IT infrastructure team should be responsible for physically attaching the labels to the conduits. They should measure out five-metre intervals along each conduit and apply the labels marked 'TS RUN' to ensure visibility.
- The security officer should periodically inspect conduits to verify labels are intact and clearly visible. Use a checklist during walk-through inspections to ensure every five metres of the conduit is labelled as required.
- The procurement team should document the purchase and acquisition of the labels. Keep records of these purchases including supplier details and specifications of the labels to ensure compliance with security standards.
- The IT oversight team should keep a maintenance log for conduit labelling. Record the date of each inspection, any issues identified, and corrective action taken to maintain proper labelling.
Audit / evidence tips
- AskThe maintenance log of conduit labels: Request to see the documented records of label checks and any corrective actions taken GoodRecord shows consistent checks at required intervals
- AskThe documentation of label purchases including specifications. Check for supplier details and compliance with size and content requirements GoodConfirms labels meet the 2.5 cm x 1 cm size and 'TS RUN' marking
- AskHow they ensure conduits are properly labelled and maintained. Listen for details about the processes in place for regular checks and the handling of non-compliance GoodIncludes regular check procedures and past compliance actions
- AskAn IT or security staff member to demonstrate how they check conduit labelling. Observe the process and measures they take if a label is missing or damaged GoodDemonstration shows adherence to the procedure and corrective steps
Cross-framework mappings
How ISM-0201 relates to controls across ISO/IEC 27001, ISO/IEC 42001, Essential Eight, and ASD ISM.
ISO 27001
| Control | Notes | Details |
|---|---|---|
| layers Partially meets (2) expand_less | ||
| Annex A 5.12 | ISM-0201 mandates a specific handling safeguard for TOP SECRET environments by requiring conduits to be clearly identified as TOP SECRET ... | |
| Annex A 5.13 | ISM-0201 requires very specific physical labelling of TOP SECRET conduits (minimum label size, five-metre intervals, and the marking 'TS ... | |
These mappings show relationships between controls across frameworks. They do not imply full equivalence or certification.