This device belongs to the Vigilohm range designed to monitor ungrounded/IT electrical networks, in accordance to installation and products standards. According to standards, it is recommanded to equip your systems with Insulation Monitoring Devices (IMD). It is dedicated to monitoring large and disturbed AC, DC and ACDC systems. This instrument provides overall insulation monitoring of electrical installations by injecting a low-frequency AC voltage between the installation and earth. Settings are available on the front of the device, through the function buttons. Several variables are available: network type, alarm and pre-alarm thresholds and others. Those settings are sealable. It monitors networks up to 760V AC when connected to neutral, 440V AC when connected to line, and 500V DC. With a capacitance reading up to 999microfarad. The black and white screen can displays insulation resistance from 100 ohms to 999 kilohms, capacitance and temporary faults. The device can schedule auto-test, and a button can launch a on demand test. In case the system insulation resistance drops below the set threshold, meaning a ground fault occurred, an alarm is triggered thru the XM output relay. Once no fault is monitored, the alarm is cleared, the alarm relay is back to normal. The device can be supplied by a 220V AC to 240V AC source with a tolérence of plus 10% or minus 15%. This product is installed flush mounted, an enclosure door for example. ingress protection is IP30 when flush mounted. Can be associated with XD301/312 for automatic fault locating, or with XL308/316 for distributed measurements. The monitoring device is equipped with a Vigilohm System Bus, to communicate with a supervision, an interface XLI300 is necessary.