Installation methods for CT 167 type cables

This cable must not be kinked, crushed, or stretched. It must not be forced into sharp bends. When running this cable think of it as being a bit like small bore central heating pipe. The main difference, though, is that if you damage copper pipe it’s fairly obvious, but if you damage this cable the fault won’t show up until the cable is brought into use.

Where the cable runs horizontally along brickwork, right angle corners are a problem. The cable must not be pulled tightly around the corner. If possible knock out a bit of mortar on the corner, so the cable can cut the corner. Even so, the corner needs to be taken gently, without putting the cable into a tight bend.

Where the cable passes through a wall, the hole should if possible be angled to minimise the bend the cable must take at each side. Even so, the entry and exit must be made without a sharp bend.

Because this cable cannot be forced into sharp bends the finished installation might not be as neat as desired. For this reason visible external runs should be avoided wherever possible. It is often worth the extra effort to find a route through the loft, cellar, or other hidden space.

If open ends are left overnight or during rain they must be left hanging downwards and temporarily sealed with tape.

Cable clips should be spaced 400mm max on horizontal runs and every four courses of brickwork on vertical runs. Clips should be the correct size. Clips intended for 2.5 T&E mains cable, etc must not be used, because they might squeeze the cable and cause impedance ‘bumps’.

CT125 cable needs similar treatment to CT167, but the bend radius is less and it is usually easier to carry out a tidy installation.

The direct burial versions of these cables are unsuitable for anything except underground use. They are stiff and bright green, so tidy installation is virtually impossible.