User's Manual

Page 16
X75 SERIES - Mk3 Controller
INSTALLATION & OPERATING MANUAL
Manual No. x75mk3-11
x75-man-Rev11-0815.indd
11.0 MAKING CONNECTIONS TO THE X75
11.1 DCLoadConnections
The DC load distribution connections at the rear left of the unit are clearly marked
as follows:
11.1.1 Circuit breaker option.
For each load circuit there are two terminals marked V1, V2, V3, V4 and V5
respectively for the DC ‘feed’ and two marked RTN for the DC ‘return’.
11.1.2 GMT Fuse option.
For each load circuit there is one terminal marked V1 through to V10
respectively for the DC ‘feed’ and one marked RTN for the DC ‘return’.
Note that in the case of -48VDC system the ‘feed’ terminals are at a negative potential
with respect to the ‘return’ terminals. In the case of +24VDC and +12VDC systems
the ‘feed’ terminals are at a positive potential with respect to the ‘return’ terminals.
When connecting to the DC load terminals it is important to ensure that the cables
used are adequately sized to carry the expected load current for the circuit in question.
The maximum current rating for the individual load terminals is 32A, but where
long cable runs to the load are expected care should be taken to avoid unacceptable
cable voltage drop; this is most likely to occur at currents in excess of 20A if only a
single feed and return cable are employed. It is recommended that for circuits where
a 20A or greater breaker is tted pairs of feed and return cables are installed.
The terminals can accommodate wire sizes in the range #24AWG to #12AWG.
The table below gives recommended cable sizes for the available circuit capacities
assuming semi-conned conditions.
Circuit Rating Minimum Cable Size
½A , ¾A, 1A,
1⅓A, 2A, 2½A
24AWG
3A, 5A 22AWG
10A. 12A 18AWG
15A 16AWG
20A 14AWG or 2 x 18AWG
25A, 30A 12AWG or 2 x 16AWG
Fi
gure6-RecommendedLoadCircuitWireSizes