Ordering Information Model 5550 Mechanical Vibration Switch Hazardous Area Rating 1 UL US/CA Explosion Proof , silver contacts(1)(2) Class I, Div 1, Groups C,D Class II, Div 1, Groups E,F,G Relay Contacts 2 DPDT, Silver, 15A(1)(3) Reset / Startup Delay Coil Holding Strength(3) 3 10g Reset / Startup Delay Coil Voltage 0 None(4)(5) Wiring Entry / Mounting Hole Pattern(6) 2 ¾” NPT / Metrix 5097, VS-2 EX, or 366 Environmental Rating 1 NEMA 4X / IP66 Options A=0 through A=4 are only compatible with B=1 or B=2. Options A=5 through A=9 are only compatible with B=3 or B=4. UL US/CA approvals require tapered threads for conduit and are not compatible with option E=4, 6, or 8. INMETRO approvals (A=11) available with silver relay contacts only (B=1 or B=2)If left blank, option 0 is provided.When D=0 (no reset /startup delay coil), the C option is ignored regardless of which value is selected. All switches ship with a fullscale range of approximately 16gs. Consult Figure 1 for mounting plate dimensions corresponding to E options.