本指南包含接地电流和电压互感器二次电路以及连接设备外壳的一般和具体建议。建议的操作规程适用于所有此类变压器，包括电容式电压互感器和线性耦合器，无论一次电压、一次绕组是否连接到电源电路或在电源电路中，或作为辅助电流互感器或电压互感器连接到其他变压器的二次电路中。尽管本指南中的大多数图表显示了中继应用，但推荐的做法同样适用 至使用仪表变压器的计量和其他区域。在某些情况下或某些类型的安装中，如果不接地所获得的优势被认为超过了接地所获得的优势，则允许或有时需要接地的例外情况。 本指南的范围包括目前使用的接地实践和之前未报告的实践。具体来说，包括对北美以外的接地实践的审查。

This guide contains general and specific recommendations for grounding current and voltage transformer secondary circuits and cases of connected equipment. The practices recommended apply to all transformers of this type, including capacitive voltage transformers and linear couplers, irrespective of primary voltage or whether the primary windings are connected to, or are in, power circuits or are connected in the secondary circuits of other transformers as auxiliary current transformers or voltage transformers. Although most diagrams included in this guide show relaying applications, the recommended practices apply equally to metering and other areas where instrument transformers are used. Exceptions to grounding are permissible or sometimes required where advantages obtained by not grounding, in certain instances or in certain types of installations, are considered to outweigh the advantages obtained by grounding. The scope of the guide includes grounding practices presently used and practices that were not previously reported. Specifically, a review of other than North American grounding practices is included.