PD Devices MDSP3 series surge protectors

The PD Devices MDSP3 series surge protectors provide protection against incoming high-voltage spikes and slower rise time disturbances for three-phase (415 V) circuits.

Designed for use on incomers at main switchboard level, they can be combined with PD devices suitable for lower transient capacity at sub-distribution board level.

The devices are suitable for power lines carrying up to 100 A and provide protection between phase, phase to neutral, phase to earth and neutral to earth.

They can be employed on higher-rated current circuits provided appropriate fusing is installed upstream. They are parallel devices and are readily retrofitted. Modular in construction, the appropriate protection level can be selected for customised protection levels.

Three basic surge current level modules can be selected: 90, 150 and 300 kA for line transient current, and 150 kA capacity neutral-earth module is also available. The standard MOV technology can be substituted for fast-acting silicon avalanche diodes.

They are two-stage devices. Under normal low-energy transient operation only the first stage will operate, with automatic reset occurring after the transient has passed.

A green LED indicates that full protection is again available after the transient has occurred. As surge currents in excess of the module rating, although clamped, may damage the first section, the indication is provided by a red LED and the device should be replaced.

Remote signalling options are available as NC or NO contacts in order to operate alarms, etc.

The devices comply with IEEE C62.41 1991, UL 1449-1985.