Experiments were performed to carefully characterize the influence of ambient temperature and incident heat flux on the horizontal flame spread over wires and cables. Results show that the flame spreads evenly along the wire, and the flame spread rate slightly increases with the ambient temperature increasing with a maximum increase of 16 %. However, the change of the flame front position with time for the cable presents a piecewise linear function, and an accelerating process exists. As the incident heat flux increases, the flame spread rate increases significantly with a maximum increase of 110 % and 113 % for both single and double cable. There is no spreading flame over the cable below a lower limit of the incident heat flux. The fastest flame spread along the cable occurs when the incident heat flux causes the flame to extend to the end of the fuel instantly. Compared to the single cable, the flame spread rate of double cable is increased by 13.6%–16.2% due to the enhanced heat feedback by the flame interaction effect. The difference in flame spread behavior in this work may be ascribed to different physical configurations, chemical compositions, reaction mechanisms, and heat transfer mechanisms.