The CTW Series are clamp-on current transformers that can be installed much easier than conventional current transformers, whereby saving installation cost. These transformers are particularly useful when expanding existing system since you can attach them to a cable without having to cut it. Standard lineup includes 100 A, 200 A, 500 A and 800 A models. Also compact and light-weight 100 A and 300 A models are available. Each of CTW models contains a built-in device for suppressing hazardous voltages that prevents a burnout or outage at the open-circuit of secondary line.