Owner`s manual
© 2009 Magnum Energy IncPage 20
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:
Read all instructions and cautionary markings located at the beginning of this manual
and in the pre-installation section, before installing the inverter and batteries.
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.
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•
•
•
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.
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 wires ability to safely handle the inverter’s maximum load current. After determining
the proper AC wire sizes, they are required to be protected from short circuits and overloads by
an overcurrent protection device and have a means to disconnect the AC circuits.
The MS Series provides a terminal block (see fi gure 2-10) that allows the AC input and output wiring
to be permanently wired. This terminal block allows a service/distribution panel (main panel) to
be wired to the inverter’s input and a dedicated panel (sub-panel)
1
between the inverter’s output
wiring and the AC loads. These systems use the circuit breakers provided in the panels as the
overcurrent protection and the AC disconnect device.
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.
When in the Standby mode, the full AC continuous pass-thru capacity of the MS Series inverter/
charger is 30 amps for each AC leg
2
(AC HOT 1 and AC HOT 2), However the AC HOT 1 and AC HOT
2 may be combined to obtain a 60 amps pass thru capability (see fi gure 2-12 for the SISO-60A
confi guration). For a 30 amp continuous pass-thru capability, each AC HOT input to the inverter
requires a 30 amp continuous duty rated breaker
3
, which corresponds to a minimum cable size
of #10 AWG
4
in conduit. 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
3
,
which corresponds to a minimum cable size of #6 AWG
4
in conduit. If you are using other circuit
breakers/wire sizes, refer to the appropriate electrical codes for proper 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.
Note 1 - Breaker models (-15B and -20B) do not require a dedicated inverter panel (i.e. sub-panel).
Note 2 - On breaker models (-15B and -20B), the pass-thru current is limited by the output breaker size.
Note 3 - The breaker must be derated by 80% if not rated for continuous duty. The NEC requires that circuits
are not to be operated continuously at more than 80% of rating unless listed with a 100% continuous rating.
Note 4 - Copper wire should be rated with 90°C insulation at an ambient temperature of 30°C (86°F).