IEC 60364-7-721:20 17（E）规定了适用于用于居住目的的房车的电路和设备的特殊要求。与上一版相比，此新版本包括以下重大技术变更: -穿过气瓶隔间的电缆现在要求气瓶底座上方的最小高度不小于500mm； -现规定每个独立装置须设有其本身的主隔离开关，该主隔离开关须断开所有带电导线，并须适当地放置在房车内容易接近的位置。

IEC 60364-7-721:2017(E) lays down particular requirements applying to electrical circuits and equipment intended for the use of the caravan for habitation purposes. This new edition includes the following significant technical changes with respect to the previous edition:
- a minimum height of not less than 500 mm above the base of the cylinders is now required for cables passing through the gas cylinder compartment;
- it is now required that each independent installation shall be provided with its own main isolating switch which shall disconnect all live conductors and which shall be suitably placed in a readily accessible location in the caravan.