From 1 January 2019, regulation 521.10.202 requires cables to be adequately supported against their premature collapse in the event of a fire. This applies throughout the electrical installation and not just in escape routes. This new requirement will make it compulsory to use metal cable fixings within the whole installation and not only on fire resistant cables. This does not mean that every cable clip must be non-metallic but the cable must be fully supported in the event of a fire.
Cable clip nails are hardened, and usually go into masonry. If getting them in proves impossible, its worth trying the vertical mortar joints rather than horizontal. The other option is pin plugs. These are little wallplugs designed for pins. Or any type of resin glue can go into masonry holes instead, and the cable clips whacked in once set.
Mortar v brick
Consistent spacing looks much neater than spacing estimated by eye. The quickest way is to cut a piece of card to the fit the gap between clips.
Maximum permitted distance between cable fixings:
- PVC cable upto 9mm dia: horizontal 25cm, vertical 40cm
- PVC cable 10-15mm dia: horizontal 30cm, vertical 40cm
- PVC cable 16-20mm dia: horizontal 35cm, vertical 45cm
- PVC cable 21-40mm dia: horizontal 40cm, vertical 55cm
- MICC upto 9mm dia: horizontal 60cm, vertical 80cm
- MICC 10-15mm dia: horizontal 90cm, vertical 1.2m
- MICC 16-20mm dia: horizontal 1.5m, vertical 2m
- For flat cables, the widest dimension is regarded as the diameter
Standard cable clips come in flat and round varieties. There are slight differences in proportions between T&E, twin and 3&E clips.
As well as white & grey clips, red & orange are also used with fire alarm cable.
- P clip
- metal strap that wraps round the cable, sleeved with plastic, hole at each end of strap for a single fixing. Mainly used with pyro. Much more fire resistant than plastic clips.
- Buckle clip
- thin metal strap with a slot in a wider bit at one end, and a nail through the middle. Less visually instrusive than plastic clips. Seldom used now. Picture above
- 2 cable clip?
- Much like a standard plastic cable clip, but fixes 2 cables and has 2 nails, one on each side of the cables. Not popular.