Johnson Controls Metasys N2 - Page 41

Network Communications—N2 Communications Bus
41
SURGE1
Metal Enclosure
NEU
HG
Building TwoBuilding One
2
4
6
8
10
1
3
5
7
9
Surge
Protector
N2+
N2-
N2 REF
SFT GRD
HRD GRD
ProtectedUnprotected
2
4
6
8
10
1
3
5
7
9
Surge
Protector
Protected
Unprotected
N2 Bus
N2+
N2-
REF
SFT GRD
HRD GRD
NCU
HG
Metal Enclosure
HG
HG
NCU/NEU - Unshielded N2 Bus
Metal Enclosure
NEU
HG
Building TwoBuilding One
2
4
6
8
10
1
3
5
7
9
Surge
Protector
N2+
N2-
N2 REF
SFT GRD
HRD GRD
ProtectedUnprotected
2
4
6
8
10
1
3
5
7
9
Surge
Protector
Protected
Unprotected
N2 Bus
N2+
N2-
REF
SFT GRD
HRD GRD
NCU
HG
Metal Enclosure
HG
HG
NCU/NEU - Shielded N2 Bus
HG
At NCU, wire shield to HRD GND connection.
For surge protector's hard ground, use 12 AWG stranded wire, 4.57 m (15 ft) maximum length.
Make sure wires entering surge protector's enclosure are not close to wires leaving enclosure.
Notes:
For surge protector's hard ground, use 12 AWG stranded wire, 4.57 m (15 ft) maximum length.
Make sure wires entering surge protector's enclosure are not close to wires leaving enclosure.
Notes:
N2 Bus
N2 Bus
N2 Bus
N2 Bus
+
-
R
+
-
R
+
-
R
+
-
R
S
S
S
S
+
-
R
+
-
R
+
-
R
+
-
R
Figure 24: Installing Surge Protector for NCU/NEU