Magnum Energy MS Series - Manual (Page 30)

©
2012 Magnum Energy, Inc. Page 21
Installation
2.5 AC Wiring
This section provides information on how to make the AC connections to the inverter using the
correct AC wire size and corresponding overcurrent protection.
2.5.1 Pre-AC Wiring Requirements
CAUTION: Before installing any AC wiring, review the safety information at the
beginning of this manual and the following to ensure a safe and long-lived system:
• Always use properly rated circuit breakers. If using an electrical sub-panel, circuit
breakers can be moved from the main electrical panel to the sub-panel only if the
breakers are also listed to be installed in the sub-panel.
• AC wiring must be no less than #10 AWG (5.3 mm 2 ) gauge copper wire and be
approved for the application (i.e., residential, RV, or marine wiring).
• DO NOT connect the inverter’s output to an AC power source. This could cause
severe damage to the inverter and is not covered under warranty.
• The wire sizes recommended in this manual are based on the ampacities given in
Table 310.16 (in conduit) or Table 310.17 (in free air) of the National Electrical Code.
ANSI/NFPA 70, for 75ºC (167ºF) copper wire based on an ambient temperature of
30ºC (86ºF).
WARNING: To reduce the risk of fi re, do not connect this inverter to an AC load center
(circuit breaker panel) having multi-wire branch circuits connected.
Note 1 – On -15B and -20B models, the pass-thru current is limited by the inverter’s output breaker size.
Note ² – The -15B and -20B models have a single AC input and cannot be confi gured for a 60-amp pass-thru
capability.
2.5.2 AC Wire Size and Overcurrent Protection
The AC input and output wiring must be sized per the local electrical safety code requirements
to ensure the wire’s ability to safely handle the inverter’s maximum load current. The AC wiring
must be protected from short circuits and overloads by an overcurrent protection device and have
a means to disconnect the AC circuits. AC overcurrent protection is not included in the inverter
and must be provided as part of the inverter installation. The AC overcurrent protection device
must be a circuit breaker or a fuse/disconnect and be properly sized and branch circuit rated for
the wire it is protecting and the appliances being powered.
Info: When wiring the AC input and output circuits, we highly recommend a full system
Inverter Bypass Switch. This simple item provides a convenient way to isolate the
inverter for battery maintenance, and it could save you hours of downtime—if you ever
need to service your inverter—by enabling you to continue to power your AC loads
without any re-wiring. Because we think it is an essential part of an inverter system,
every Magnum panel (MMP/MP Series) is equipped with an Inverter Bypass Switch.
When the inverter is in Standby mode, the full AC continuous pass-thru capacity of the MS Series
inverter/charger is 30 amps for each AC leg 1 (AC HOT 1 and AC HOT 2). For a 30-amp continuous
pass-thru capability, each AC HOT input to the inverter requires a 30-amp continuous duty rated
breaker², which corresponds to a minimum cable size of #10 AWG (in conduit). However, the AC
HOT 1 and AC HOT 2 may be combined to obtain a 60-amp pass-thru capability² (see Figure 2-10).
When tying the AC HOT 1 and HOT 2 together for a 60-amp continuous pass-thru capability, the
AC input to the inverter requires a 60-amp continuous duty rated breaker, which corresponds to
a minimum cable size of #6 AWG (in conduit). If you are using other circuit breakers/wire sizes,
refer to the appropriate electrical codes for sizing requirements.
CAUTION: The inverter’s internal AC transfer relay contacts are rated for 30 amps
(each leg), the pass-thru current for relay contact must be no greater than 30 amps
or damage to this relay may occur.