Ii.c Discrimination; Ii.d Surge Suppression Device Protection; Ii.e Ac Cable Installation And Surge Protection - NewMar Commander II Series Manual

II.C Discrimination

Discrimination ensures that the upstream circuit breaker or fuse does not blow if a rectifier input is faulty (in a short circuit
manner). Therefore, it is important to ensure the upstream protection discriminates with the internal fuse of the rectifier. The
fuse used in the RM3048 is a slow-blow 25A fuse.
Preferably use either a 50A, D-curve, or a 63A, C or D curve breaker. If a fuse is used upstream, then any BS88 or NH g style
fuse will discriminate above 50A. A minimum circuit breaker to use for this system is a 50A.

II.D Surge Suppression Device Protection

It is recommended to have Type 2 Surge Protection Devices (s) (as defined by IEC 61643-11) upstream to the supplied
cabinet. These devices are rated for repeated strikes of 20kA (8/20μs waveform), and single shot protection of 40kA.
It is important that upstream Type 1 protection is also provided on site. To ensure correct operation of the s, at least 10m of
AC feeder cable is fitted between the Type 1 and Type 2 protection. If the distance between the AC incoming distribution
board and the DC Power System is less than 10m, then loop the cable until at least 10m of cable is used. This ensures
correct de-coupling of the devices.

II.E AC cable installation and surge protection

The following precautions MUST be adhered to when installing AC cabling.
1. Avoid running input and output cables from AC Surge Protection Devices together:
AC to DC Power
System
Significant coupling
between unprotected and
protected AC line negates
the effectiveness of SPD
2. Avoid "T" Connections:
Incoming
AC
SPD
( Type 1)
"Tee" connection not
recommended
Appendix III NEWMAR E
NewMar warrants that its products shall be free from defects of material or workmanship under use consistent with correct
installation and commission, normal operation, product specifications, NewMar's written instructions, and regional standards
compliance, for a period of one (1) year from the start date. The start date shall be defined as (a) the date the product is
Technical Service: 800-241-3897 • E-mail: techservice@newmarpower.com
Incoming
AC
SPD
( Type 1)
AC to DC Power
System
Tee connection introduces
significant impedance to
surge, reducing the
effectiveness of the SPD (by
approx. 0.7 to 0.8V/mm)
S
NERGY TANDARD
Newmar • 1580 Sunflower Ave, Suite 100, Costa Mesa, CA 92626
Incoming
AC
SPD
( Type 1)
Incoming
AC
SPD
( Type 1)
"Kelvin" connection
recommended
L W
IMITED
AC to DC Power
System
Minimal coupling
between Protected and
Unprotected AC lines
AC to DC Power
System
P
ARRANTY OLICY