Overhead Electrified Cable Ahead Traffic Sign Diagram 779 RA2 Post Mountable Size:900mm Tri Values of retroreflection as shown Scalpels Blades & Handles Values of retroreflection as shown in Table 1 are complied with when measured in accordance with the corresponding specifications using CIE standard illumit A As per the UK Highways Traffic Sign Manual Chapter 4 Warning Signs page: 70 The following advice is given: These signs MUST show the safe vehicle height of the cable to ensure all vehicles are away if they can fit safely under the cable see Figure 20 11) warns of a place where a road passes under an electrified overhead power cable