Magnum Energy MP Extension Box (MPX Series) User Manual

Page 22

3.0 Installation

AC Connections

To view the AC connection points inside the MP enclosures, review Figures 3-18a/b and 3-19a/b for

the MPSL-30D and MPSH-30D models, Figure 3-21a/b for the MPSL-60S model, or Figure 3-22a/b

for MPDH-30D model.
If using an MS-PAE Series inverter, the full AC continuous pass-thru capacity of these inverters is 30

amps for each AC leg (AC LEG 1 and AC LEG 2), and requires a maximum 30 amp breaker on each

AC input to protect the inverter’s inputs. This correlates with the MPSL-30D, MPSH-30D, and the

MPDH-30D enclosures, which include a dual 30 amp input inverter breaker and a minimum cable size

of #10 AWG in conduit.
In MS4024 inverters, the AC LEG 1 and AC LEG 2 may be combined to obtain a 60 amps pass-thru

capability. When tying the AC LEG 1 and AC LEG 2 together for a 60 amp continuous pass-thru ca-

pability, the AC input to the inverter requires a 60 amp breaker. This correlates with the MPSL-60S

model, which includes a single 60 amp breaker and requires a minimum cable size of #6 AWG in

conduit. Refer to Figure 3-20a for info on wiring to the MS4024 inverter.
If you are using other circuit breakers/wire sizes, refer to the appropriate electrical codes for proper

sizing requirements.

DC Cable Connections

Before proceeding with the DC wiring, review the instructions in Figure 3-17 to ensure proper DC

cable stacking and connections. Do not put anything between the DC cable ring lug and the battery

terminal post or the fl at metal part of the inverter’s DC terminal. When connecting the DC cable

to the battery or inverter DC terminals, the cable should be placed directly against the inverter or

battery terminals. Incorrectly installed hardware causes a high resistance connection which could

lead to poor inverter/charger performance, and may melt the cable and terminal connections.
Make sure to properly connect the DC cables and correctly stack the hardware. Tighten the terminal

connections from 10 to 12 ft lbf (13.6 to 16.3 N-m).

CAUTION: The DC terminal and Flange/Kep nuts supplied with the inverter are made

of stainless steel, which have a high likelihood of seizure. To help prevent the bolt and

nut from seizing — causing the bolts to strip or snap/break-off — the use of anti-seize

lubricant is highly recommended.

Info: If antioxidant grease or spray is used, apply it after all the connections have been

made and are properly tightened.

Info: A 1/2-inch wrench or socket is used to tighten the 5/16-18 SAE Flange/Kep nuts.

IMPORTANT: Magnum accessories (ME-ARC, ME-RTR, ME-AGS, and ME-BMK) each use a

communication chip to talk with the inverter. This communication chip is powered through the

communication lines using the B+ (battery positive) and B- (battery negative) supply. We have

found that customers are removing the battery negative circuit (B-) while the battery positive

circuit (B+) is still connected; or, they are connecting the battery positive (B+) before connect-

ing battery negative (B-). When accessories are connected to the inverter and B+ is connected

or disconnected to the inverter without a return path (i.e., B-), the communication chips/lines

become the DC return path to the battery – causing permanent damage to all connected acces-

sories on the network.
You should not have any issue with communication circuits when using the MP/MPX panels. This

is because when you open the Inverter Disconnect Breaker on the MP to power-down the sys-

tem you are opening the B+ circuit while all B- circuits remain connected. Once the system is

powered-down, you can connect and disconnect communication cables as needed. When you are

fi nished removing/adding accessories and comm cables, you can turn the Inverter Disconnect

Breaker back on to resume operation, which connects the B+ circuits (with B- circuits already

connected).
In summary: Ensure all battery negative (B-) circuits are connected before connecting

or disconnecting battery positive (B+).