Rule 307: Overhead electric lines
Overhead electric lines. Tramway overhead wires are normally 5.8 metres above any carriageway, but can be lower. You should ensure that you have sufficient clearance between the wire and your vehicle (including any load you are carrying) before driving under an overhead wire. Drivers of vehicles with extending cranes, booms, tipping apparatus or other types of variable height equipment should ensure that the equipment is fully lowered. Where overhead wires are set lower than 5.8 metres, these will be indicated by height clearance markings - similar to ‘low bridge’ signs. The height clearances on these plates should be carefully noted and observed. If you are in any doubt as to whether your vehicle will pass safely under the wires, you should always contact the local police or the tramway operator. Never take a chance as this can be extremely hazardous.
Advice, not law. This rule is not written in capitals, so breaking it is not an offence in itself — but it can still be used in evidence in court to establish liability. The rules that say MUST or MUST NOT are the ones backed by law.
5 theory test questions on this rule
From the DVSA revision question bank. These are not the questions asked in the real theory test. Each one shows the answer, the explanation, and our own note on why every other option is not it.