What it is and where it fits
The Siemens 3RT2916-1JL00-ZX90 is a SIRIUS surge suppressor with a built-in varistor and LED indicator, designed to clip directly onto size S00 contactors and relay sockets. It suppresses voltage spikes across the coil terminals, protecting the control circuit from inductive kickback when the contactor de-energizes. Rated for AC control supplies from 127 to 240 V at 50/60 Hz and DC supplies from 70 to 150 V, it covers the common control voltages found across European and North American panels. The LED gives a quick visual check that the suppressor is live and the coil circuit is energized.
Panel integration — the 9 mm slice
At 9 mm deep, 28 mm wide, and 46 mm tall, this suppressor adds negligible depth to the contactor stack. It clips onto the coil terminals of any S00-frame SIRIUS contactor or relay — no wiring needed, no extra DIN-rail space consumed. The clip-on fastening method means it seats firmly and can be removed for troubleshooting without disturbing the power wiring. The varistor design handles the energy from the collapsing magnetic field of the coil, limiting the peak voltage to a safe level for the PLC output or relay driving it. For a panel builder, this means no separate RC snubber or free-wheeling diode to mount and wire.