Johnson Controls Metasys N2 - Page 47

Network Communications—N2 Communications Bus
47
Metal Enclosure
SURGE7
Metal Enclosure
ASC
HG
Building Two
Building One
2
4
6
8
10
1
3
5
7
9
Surge
Protector
N2+
N2-
REF
ProtectedUnprotected
2
4
6
8
10
1
3
5
7
9
Surge
Protector
Protected Unprotected
REF
N2-
N2+
HRD GRD
NCM
HG
ASC
HG
HG
N2 Repeater - Shielded N2 Bus
Notes: For surge protector's hard ground (HG), use 12 AWG stranded wire, 4.57 m (15 ft) maximum length.
Soft ground (SG) the N2 Bus shield within one inch of entering the enclosure with a 560-1000 pF capacitor.
Make sure wires entering surge protector's enclosure are not close to wires leaving the enclosure.
+
-
R
+
-
R
+
-
R
+
-
R
REF
N2-
N2+
SG
S S
SS
N2 Bus
N2 Bus
N2 Bus N2 Bus
SG
Repeater
COM
D
D
COM
Side A
Side B
D
D
N2 Bus
Figure 30: Installing Surge Protector for N2 Bus Repeater