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5.3.
Upstream Over-current Protection
There are two considerations to consider when selecting an appropriate fuse/circuit
breaker.
- The upstream protection should protect the downstream cable from overload situations.
- Discrimination should be maintained with the downstream device fuses.
Cable Rating
The maximum current drawn by the DC power system is 24A from a single-
phase supply (12A per rectifier at a minimum input voltage of 175V
output power). The upstream protection device must be able to supply this
load under all conditions without tripping. Therefore, typically at least 20%
headroom is allowed for in the protection device, making its minimum rating
28.8A/ph for single phase input.
Note: The current carrying capacity of cables is dependent on the type of cable used.
Please check with your local supplier and local regulations for appropriate sizing.
5.4.
Discrimination
Discrimination ensures that the upstream circuit breaker or fuse does not blow if
a rectifier input fails (short circuit). Therefore, it is important to ensure the
upstream protection discriminates with the internal fuse of the rectifier. The fuse
used in the RM2048HE is a slow-blow 15A fuse. The tripping curve for this is
shown in Appendix 4 at the rear of this manual.
A minimum circuit breaker to use for this system is a 32A, D-curve (note, a 32A C-
curve breaker will not discriminate with the rectifier fuse). Therefore, when used
with the 2.5mm
2
cable supplied, a 20A, D-curve breaker should be used.
Alternatively, a 40A C-curve breaker, or greater, can be used. However, AC cable
provided may have to be replaced for a larger cable
If a fuse is used upstream, then any BS88 or NH g style fuse, of 20A or greater rating
will discriminate.
5.5.
DC Cabling
CAUTION:
Use extreme care when fitting batteries & their connections. Remove all jewelry
and rings from oneself prior to commencing the installation. Always use insulated tools
when fitting batteries and take extreme care not to short terminals when working on
them.
Battery Connections
Newmar • 1580 Sunflower Ave, Suite 100, Costa Mesa, CA 92626
Phone: 714-751-0488 • E-mail: techservice@Newmarpower.com
1
.
2x +12V/-12V or
1x +12/-12V & 1x +24V/-24V or
2x +24V/-24V
and full
ac
10
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