Measurement of the 7-shaped clips on the cable tray

7-shaped clips are used to secure cables to trays, and their spacing and sizing depend on cable type, tray design, and load requirements. Clip Function and Design7-shaped clips are typically used to hold cables securely on ladder or perforated cable trays without causing mechanical strain or damage. They are designed to fit over the tray rungs and wrap around the cable bundle, providing support while allowing some flexibility for thermal expansion and vibration.

Spacing Guidelines

The spacing of 7-shaped clips is determined by the weight and diameter of the cables, as well as the type of tray: Small-diameter control or instrumentation cables: Clips or supports are generally spaced 6 to 12 inches apart along the tray rungs to prevent sagging and maintain neat installation (Eaton B-Line series guidance)Larger power cables: Clips may be spaced 9 inches or wider, depending on cable stiffness and bending radius requirementsLong spans: For cable trays spanning longer distances, clip spacing should follow the 1/4 span rule, where clips are placed at approximately one-quarter of the distance between tray supports to minimize deflection and stress at splice points These intervals ensure that cables are not exposed to undue mechanical strain and comply with BS 7671 and IEC 61537 standards for cable support.

Material and Fire Resistance

Clips should be made from fire-resistant materials to prevent premature failure in case of fire, as required by BS 7671 Clause 521. 10. 202.

Metal clips are preferred for exposed or high-load installations, while high-quality polymer clips may be used for indoor, low-load applications.

Practical Considerations

Ensure the clip size matches the cable bundle diameter; too tight can damage insulation, too loose can allow saggingMaintain minimum bending radii for cables when positioning clips to avoid stress on terminationsFor ladder trays, clips are often installed directly on rungs, while for solid-bottom trays, clips may attach to the tray surface or side railsSummaryWhile the exact physical dimensions of 7-shaped clips vary by manufacturer, the key factors are cable diameter, tray type, load, and spacing. Following recommended intervals (6–12 inches for small cables, 9 inches or more for large cables) and using fire-resistant materials ensures compliance with IEC 61537, BS 7671, and NEMA/NEC standards, providing safe and durable cable support.