Calculating Oglaend Smart Cable Cleat Spacings On Cable Ladder Installations

Published 02 Apr 2019

Cleats & Clamps | LV MV HV Cables

• uploaded by - Chris Dodds Thorne & Derrick Sales & Marketing Manager

Oglaend

Cable Cleats & Clamps

Theoretical Background
Source: EFI report TR A3901 Jan 1993

The following article and formula enables the calculation of cable cleat/clamp spacings to enable adequate short-circuit restraint of LV MV HV cables onto cable containment in onshore or offshore medium/high voltage substations.

Fb=(0.5 x 0.2 x kApeak2)/a where:

• Fb: Force (N/m)
• kA.peak: Short circuit current peak value (kA)
• a: Distance between the centre points of the cables/cable diameter
• Cable run. Length of cable run

Recommended distance between Oglaend Smart Cleat clamps mounted on cable ladders is shown in the image below:

The calculated number of Oglaend cable clamps is included using Smart Securing Plate in both ends of the cable run.

The distance between the cable clamps should be reduced in vertical and horizontal bends.

The recommended maximum distance between Smart Cleats is 0.9m.

Recommended distance between Oglaend Smart Cleat clamps when not installed on cable ladder is shown in the image below:

At the start and at the end of the cable run it is recommended to install 3 cable cleats with 150mm distance between them. The calculation above is including these cable cleats.

The distance between the cleats must be reduced during vertical and horizontal bends. The maximum recommended distance between Smart Cleats is 0.9m.

Smart Securing Plates

Secure plates are strongly recommended to be used at both ends of a trefoil cable run. Realistic tests done on several cable lengths and clamp distances confirms the theory that the cable must be additionally secured at both ends to reduce arching and eliminate deformation and stretch marks on the cable.

Smart Securing Plates Part References

Distance between Smart Cleats manufactured by Oglaend given that the distance between the centre points of the cables or the cable diameter is 42mm

Smart Cleat

• Smart Cleat saves space – both in cable clamp height and width
• Plastic liners are not required for trefoil installations due to the design of the cable clamp providing a smooth surface
• Manufactured by Oglaend the Smart Cleat is suitable for fixing to preslotted rung design
• Fixing bolts are easily accessible from underneath the rung
• Low weight – compact and light design cable clamps
• The design fixes the cables so close to the rungs, that the rungs in between cleats give full support for distribution of load
• Low product price and low installation cost
• Smart Cleat trefoil cover cables from Ø 25 mm – Ø 99 mm and Smart Cleat single cables from Ø 39 mm – Ø 99 mm
• Smart Cleat is tested up to 160 kA-Peak
• Smart Cleat single and trefoil are certified by DNV according to IEC 61914

Further Reading

• Cable Clamps: The BAND-IT BAND-FAST Range – IEC61914 Tested
• Stainless Steel Cable Cable Cleats v Cable Ties – By Ellis Patents
• Understanding the Importance of Cable Cleats in Offshore Industries
• Stainless Steel Cable Cleats
• A60 H120 Pipework Fire Protection For Offshore Bulkheads & Decks
• IEC 61914 – Cable Cleats & Short Circuit Protection Calculations

Cable Cleat Distributors | Ellis Patents | Torgy | id-Technik

LV, MV & HV Jointing, Earthing, Substation & Electrical Eqpt

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