SCT 013-100 Current transformers (CTs) are sensors that are used for measuring alternating current up to 100 Amperes. They are particularly useful for measuring whole building electricity consumption (or generation for that matter). These are particularly suitable for DIY use, it can be clipped straight on to either the live or neutral wire coming into the building without having to do any high voltage electrical work.
This non-invasive current sensor clamped around the supply line can measure a load up to 100 Amps, and allow you to calculate how much current pass through it. It can be useful for building your own energy monitor or for building an over-current protection device for an AC load. This current clamp can be used to detect a current of up to 100A. Simply clip it around the current source that you wish to measure and it will produce a (very) small AC voltage proportional to the current. The cable is terminated on one end with a standard 3.5mm jack (like a headphone jack). Use this to build your own energy monitor and keep your power usage down or use it to build an over-current protection device for an AC load.