Connecting the Outputs
Series N6700 User’s Guide
19
Wire Size
WARNING
FIRE HAZARD
Select a wire size large enough to carry short-circuit current
without overheating. To satisfy safety requirements, load wires must be
heavy enough not to overheat while carrying the short-circuit output current
of the unit (refer to the following chart).
Along with conductor temperature, you must also consider voltage
drop when selecting wire sizes. The following chart lists the
resistance for various wire sizes and also the maximum lengths to
limit the voltage drop to 1.0 volts for various currents.
Wire size
Current-carrying capacity (Amps)
Resistance
Max. Length to Limit Voltage to 1 V/Lead
for 5 A for 10 A for 20A
AWG
2 wires bundled
4 wires bundled
Ω
Ω
Ω
Ω
/foot
Wire length in feet
20
7.8
6.9
0.0102 20 10 5
18
14.5
12.8
0.0064 30 15 7.5
16
18.2
16.1
0.0040 50 25 12.5
14 29.3
25.9 0.0025
--
40
20
12
37.6
33.2
0.0016
-- -- 30
Area in mm
2
2 wires bundled
4 wires bundled
Ω
Ω
Ω
Ω
/meter
Wire length in meters
0.5 7.8 6.9 0.0401
5
2.4
1.2
0.75
9.4
8.3
0.0267 7.4 3.8 1.8
1 12.7
11.2 0.0200
10
5
2.6
1.5 15.0 13.3 0.0137
14.6
7.2
3.6
2.5 23.5 20.8 0.0082
--
12.2
6
Notes: 1. Capacity for AWG wires derived from MIL-W-5088B. Max. ambient temp: 55°C. Max. wire temp: 105°C.
2. Capacity for metric wires are derived from IE Publication 335-1.
3. Capacity of aluminum wire is approximately 84% of that listed for copper wire.
4. Because of wire inductance considerations, it is recommended that you keep your load leads twisted, tie
wrapped, or bundled together and less than 50 feet (14.7 meters) in length per lead.
Note that the minimum wire size required to prevent overheating as
shown in the above chart may not be large enough to prevent OV trip
and to maintain good regulation. Under most conditions, the load
wires should be heavy enough to limit the voltage drop to no more
than l.0 V per lead.
NOTE
To help prevent nuisance tripping of the over-voltage circuit, select a wire size
sufficient to handle the FULL output current of the unit no matter what the
intended load current or current limit setting
Load lead resistance is an important factor relating to the CV
stability of the instrument when remote sensing capacitive loads. If
high capacitance loads are expected, you should not use wire gauges
heavier than 12 to 14 AWG for long runs of load lead.
