Download Gassonic Observer-H Instruction Manual

AWG
mm2
Ohms per Km
Ohms k feet
10
5.27
3.28
1.00
12
3.31
5.21
1.59
14
2.08
8.29
2.53
16
1.31
13.2
4.01
18
0.823
20.95
6.39
20
0.519
33.31
10.15
Table 31: Resistance of Copper Wire
Based on a 24 volt supply and 15 volts at the Observer-H the recommended wire sizes are shown
below.
AWG
mm2
FEET
METERS
10
12
14
16
18
20
5.27
3.31
2.08
1.31
0.823
0.519
15000
9434
5928
2347
2347
1478
4573
2880
1809
1136
715
450
Table 32: 24 VDC Cable Lengths
Use the following formula to calculate the wire size:
Cable drop per wire equals (Ein – voltage at instrument)/2
= (24 -15)/2 = 4.5 volts per wire
Resistance maximum equals cable drop divided by Current required by unit at voltage at unit
R = 4.5/0.300 = 15 ohms per cable
Ohms per cable divided by cable ohms per meter = 15/3.28 = 4573 meters for 10 AWG
European Union (EU) Approved Applications: PSU noise and ripple voltage 1.0 Vpp max. The customer
supplied PSU must comply with IEC 61010-1, limiting current to 8 A under fault conditions in order to
comply with the CE Marking requirements.
Installation and User Guide for Gassonic Observer-H (MANOBSERVER-H, Rev C/3-12)
Page 66