取得防爆合格证的空外壳内部安装无防爆认证（防爆合格证）的仪表。

取得防爆合格证的空外壳内部安装取得防爆认证（防爆合格证）的仪表。

以上两种情况，都需要取得整体防爆合格证，才可以使用在爆炸性环境。

以隔爆外壳"d"为例进行说明：

GB/T 3836.15-2017 爆炸性环境第15部分：电气装置的设计、选型和安装（IEC 60079-14：2007，MOD）

10 对隔爆外壳"d"的补充要求

10.1 总则

仅有Ex元件防爆合格证（带有符号"U"）的隔爆外壳不得安装，它们应与设备组装在一起取得设备防爆合格证。

设备不经重新评定不能改变设备的内部元件,因为忽视条件变化会导致压力重叠、温度组别变化或其他类似的可能使防爆合格证失效的情况。

IEC 60079-14：2007 Explosive atmospheres - Part 14: Electrical installations design, selection and erection

IEC 60079-14：2013 Explosive atmospheres - Part 14: Electrical installations design, selection and erection

14 Additional requirements for type of protection "d" – Flameproof enclosures

14.1 General

Only Ex "d" equipment having a complete certificate shall be installed.

Ex "d" enclosures and components having only a component certificate, i.e. marked with a "U", shall not be installed in the hazardous area unless as part of an assembly of components (now being referred to as equipment), when the components in the equipment are permitted by a full Ex certificate which may contain an "X" and the equipment label carries full Ex marking including temperature class.

Additional holes or modification to entries shall only be made into an Ex "d" enclosure by the manufacturer or an appropriately qualified certified service facility.

Alteration of the internal components of the equipment is not permitted without re-evaluation of the equipment because conditions may be created inadvertently which lead to pressure- piling, change in temperature class, or other such issues that may invalidate the certificate.

译文：

14 对隔爆外壳"d"的附加要求

14.1 通则

仅应安装具有完整证书的Ex"d"设备。

仅有元件证书（即带有符号"U"）的Ex"d"外壳和元件，不应安装在危险场所内，除非它们是元件组件（现在称为设备）的一部分，且设备中的元件被带"X"的完整防爆合格证所允许，设备铭牌有包括温度组别在内的完整防爆标志。

对Ex"d"外壳增加或改动引入孔仅应由制造商或经认证的有资质修理单位进行。

设备不经重新评定不准许改变设备的内部元件，因为忽视条件变化会导致压力重叠、温度组别变化或其他类似的可能使防爆合格证失效的情况。