13Connection of the F5 series inverters to voltage systems configured as a cor-ner grounded delta, center tap grounded delta, open delta, or ungroundeddelta, may defeat the internal noise suppression of the inverter. Increased highfrequency disturbance in the controller and on the line may be experienced. Abalanced, neutral grounded wye connection is always recommended. The threephase voltage imbalance must be less than 2% phase to phase. Greater imbal-ance can lead to damage of the inverter's power circuit.1.4.3 Disconnect switchA disconnect switch or contactor should be provided as a means of turning off thesupply voltage when the unit is not in use or when it must be serviced.Repetitive cycling on and off of the input supply voltage more than once everytwo minutes can lead to damage of the inverter.1.4.4 FusingIntegral solid state short circuit protection does not provide branch circuit protec-tion. Branch circuit protection must be provided in accordance with the Manufac-turer Instructions, National Electrical Code (NFPA70 or CSA22.1) and any addi-tional local codes.Branch circuit protection for the F5 must be provided using the fuses as listed inthe tables 1.4.4.1 and 1.4.4.2 below. The class RK5 fuses are recommend. Asan Example, use BUSSMANN type FRS-R for 480V or FRN-R for 230V. Othermanufacturers’ class RK5 fuses are also acceptable.The minimum voltage rating for protection devices used with 230V inverters shallbe 250VAC. The minimum voltage rating for protection devices used with 460Vinverters shall be 600VAC.GeneraliTable 1.4.4.1 - 230V Units* Semiconductor fuses are manufactured by Siba Fuse Inc. When using this type of fuse,this is the model number of the fuse is the fuse that must be used.SCCR UL 248 Semiconductor UL 48Unit Size /Housing[kA]rmsTYPE RK5Rating [A]TYPE LRating [A]Fuse Number* /Rating [A]MCCB [A] /Siemens Cat. No.13 / E 10 40 - - 50 140 06 80 / 8014 / G 10 50 - - 50 140 06 100 / 10015 / G , H 10 70 - - 50 140 06 80 / 8016 / H 10 0 - - - -17 / H 10 110 - - - -18 / R 100 125 - - - - 150A / DG-frame 3VL 150 UL1 / R 100 150 - - - - 150A / DG-frame 3VL 150 UL20 / R 100 175 - - - - 250A / FG-frame 3VL 250 UL21 / R 100 200 - - - - 250A / FG-frame 3VL 250 UL
