MultiPlus-II 2x120V 4.4. Connection of the AC cabling This is a safety class I product (supplied with a ground terminal for safety purposes). Its AC input and/or output terminals and/or grounding point on the outside of the product must be provided with an uninterruptible grounding point for safety purposes. This product is provided with a ground relay (relay H, see appendix B) that automatically connects the Neutral output to the chassis if no external AC supply is available. If an external AC supply is provided, the ground relay H will open before the input safety relay closes. This ensures the correct operation of an earth leakage circuit breaker connected to the output.
In a fixed installation, an uninterruptable grounding can be secured by means of the grounding wire of the AC input. Otherwise, the casing must be grounded. In a mobile installation (for example, with a shore current plug), interrupting the shore connection will simultaneously disconnect the grounding connection. In that case, the casing must be connected to the chassis (of the vehicle) or to the hull or grounding plate (of the boat). The inverter incorporates a mains frequency isolating transformer. This precludes the possibility of DC current at any AC port. Therefore, type A RCDs can be used.
In case of a boat, direct connection to the shore ground is not recommended because of potential galvanic corrosion. The solution to this is using an isolation transformer. This unit or system is provided with fixed trip limits and shall not be aggregated above 30kW on a single point of common connection. The AC terminal blocks can be found on the printed circuit board, see Appendix A. Do not invert neutral and phase when connecting the AC. The AC connections need to be made with three-wire 90єC (194єF) copper cable. AC-in The AC input cable can be connected to the terminal block ‘AC–in’. From left to right:
“N” (neutral), “L2” (phase 2), “PE” (earth) and “L1” (phase 1) The AC input must be protected by a fuse or magnetic circuit breaker rated at 50A or less, and the cable cross-section must be sized accordingly. If the input AC supply is rated at a lower value, the fuse or magnetic circuit breaker should be downsized accordingly. AC-out-1 (Maximum Torque: 2 Nm) The AC output cable can be connected directly to the terminal block ‘AC-out’. From left to right: “N” (neutral) , “L2” (phase 2), “PE” (earth) and “L1” (phase 1) With its PowerAssist feature the inverter/charger can add up to 3kVA (that is 3000 / 120 = 25A) to the output L1 during periods of peak power requirement.
Together with a maximum input current of 50A, this means that the output can supply up to 50 + 25 = 75 A. An earth leakage circuit breaker and a fuse or circuit breaker rated to support the expected load must be included in series with the output, and the cable cross-section must be sized accordingly. Victron Energy recommends using the Blue Sea systems GFCI circuit breakers PN. 309X or 310X. The maximum rating of the fuse or circuit breaker is 75A. AC-out-2 (Maximum Torque: 2 Nm) A second output is available that disconnects its load in the event of battery operation. On these terminals, equipment is connected that may only operate if AC voltage is available on AC-in-1, e.g.
an electric boiler or an air conditioner. The load on AC-out-2 is disconnected immediately when the inverter/charger switches to battery operation. After AC power becomes available on AC-in-1, the load on AC-out-2 will be reconnected with a delay of approximately 2 minutes. This to allow a genset to stabilise. Page 13 Installation MultiPlus-II 2x120V AC-in AC-out-1 AC-out-2 Rated current 50 A 75 A 50 A Recommend fuse or circuit breaker 50 A 75 A 50 A Minimum wire gauge AWG 6 AWG 6 AWG 6 Ferrule pin and stripping length 0.7 inch (18 mm) 0.7 inch (18 mm) 0.7 inch (18 mm) A 2.5 mm blade tool (e.g., a screwdriver) is required to operate the spring-loaded AC terminal blocks.