This modular surge arrester is for use in three phase systems.
The 4 DIN module wide rail mounted type 2 surge device is for TNS or PME grid connections.
These are easily pluggable surge modules and they are for testing. They meet the requirements of BS7671 amendment 1 section 534.
They can also be wired in to the circuit with the AC isolator.
Keywords: DGMTNS275, DEHN, Three Phase Surge Protection