Paragraph 3
Where a vehicle which is being used for the carriage of explosives comprises a trailer and the laden trailer is uncoupled and left on the road at a distance from the motor vehicle—
(a)
paragraph 1(a) shall not apply;
(b)
the operator, driver and any attendant of the said motor vehicle shall ensure that the trailer is equipped with at least one fire extinguisher conforming to the provisions of paragraph 1(b).